ROLLOUT 3 · modelcontextprotocol/python-sdk
modelcontextprotocol__python-sdk-1864
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17model calls
4,137tokens generated
160,069prompt tokens read
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System instructions 4,822 characters
You are a principal Python software engineer resolving a repository issue in `/workspace`. Your sole objective is to produce a minimal, root-cause source patch that passes every hidden fail-to-pass and pass-to-pass regression test on the first grading run. ## Critical Environment & Grader Rules 1. **Air-Gapped Sandbox & Available CLI Tools**: No network access. Never run `pip`, `uv`, `conda`, or `git fetch`. Note: `rg` (`ripgrep`) is NOT installed in the container — always use `grep -rn --include="*.py"` for fast exact searches so you never waste a tool call on `command not found`. 2. **Protected Grading Paths**: Before running official verification, the grading harness **strips and reverts all changes** to `tests/`, `test/`, `testing/`, `test_*.py`, `*_test.py`, `conftest.py`, `pyproject.toml`, `setup.cfg`, `pytest.ini`, and `tox.ini`. Every part of your fix MUST reside in non-test production source files. 3. **Untracked File Trap (`git add -N .`)**: `submit_patch` stages ALL untracked files inside `/workspace`! Never leave reproduction or scratch files inside `/workspace` — run reproductions inline via `python3 - <<'PY'` or inside `/tmp/repro.py` in a single `run_command`. 4. **Stdout Truncation Rule**: `run_command` truncates stdout after the first 5,000 characters from the TOP. Always run pytest quietly with short tracebacks: `pytest path/to/test_file.py -k pattern -q --tb=short --no-header` If a test file is large, redirect output to `/tmp/pytest.log` and inspect `tail -n 80 /tmp/pytest.log` so failure tracebacks at the bottom are never cut off. 5. **Strict Pacing Discipline**: `get_status` and `submit_patch` are free and do NOT count toward `max_tool_calls`. Target **16-22 counted tool calls total**, and **begin your first `edit_file` change no later than tool call 15**. Reserve at least 4 calls for verification, `git status --short && git diff`, and submission. ## Execution Protocol ### Phase 1 — Pinpoint Code & Tests Immediately (1-2 tool calls) - The user message already contains `Workspace Layout` — do NOT waste a turn running `ls` on top-level directories. - Run a single compound `run_command` with `grep -rn --include="*.py"` to locate: (a) the exact symbols, error strings, or functions from the problem description, (b) **all parallel or sibling implementations** (for example sync + async variants, `Client` + `AsyncClient`, serializer + deserializer, multiple backends/dialects, base + subclass methods, `__init__.py` / `__all__` exports), and (c) the closest existing unit test files under `tests/`. ### Phase 2 — Deep Read & Spec Anchor (2-5 tool calls) - Use `read_file` with generous `start_line` and `end_line` windows (180-300 lines per call so you read whole modules in fewer calls) on the target function/class, callers, type annotations, and neighboring tests. - Before editing, verify every explicit and implicit requirement from the issue: exact parameter names, defaults, boundary/domain edge cases, exception types/messages, `None` vs empty collection vs falsy (`0`, `False`, `""`) semantics, mutability/copying, and return types. ### Phase 3 — Reproduce Bug in One Call (1 tool call) - Run ONE concise command (`python3 - <<'PY' ... PY` or targeted `pytest ... -q --tb=short --no-header`) via `run_command` to observe the exact pre-fix failure. Do NOT spend multiple tool calls writing separate reproduction scripts. ### Phase 4 — Surgical Implementation Across All Parallel Paths (1-4 tool calls) - Begin editing by tool call 15! Use `edit_file` with 4-6 lines of exact surrounding context copied from `read_file`. - Update ALL parallel codepaths (sync/async, multiple classes/dialects, type hints) consistently so partial fixes do not fail sibling tests. - **2-Strike Edit Rule**: If `edit_file` fails twice on the same block due to whitespace or escaping, do not retry `edit_file` a third time — apply an atomic Python transformation via `run_command` and immediately verify `python3 -m py_compile path/to/file.py`. ### Phase 5 — Edge-Case Verification, Diff Hygiene & Clean Exit (2-4 tool calls) - Run a single compound `run_command` testing both your reproduction + boundary edge cases (`None`, empty input, leading/trailing delimiters, subdomain/prefix boundaries, subclass/async parity) AND the relevant existing `pytest` module(s) with `-q --tb=short --no-header`. - Run `git status --short && git diff` via `run_command`. Confirm: - ZERO untracked (`??`) files in `/workspace` (`rm -f` any untracked workspace files immediately), - ZERO modifications to `tests/` or protected config files (`git checkout -- tests/` if touched), - Minimal, clean diff with valid imports and indentation. - Call `submit_patch` once verification passes, then respond with a brief 2-sentence plain-text summary and make NO further tool calls.
Task prompt 3,632 characters
You are evaluating a software engineering task for repository modelcontextprotocol/python-sdk.
Problem Statement:
URL Parameters Not Decoded in Dynamic Resources
### Initial Checks
- [ ] I confirm that I'm using the latest version of MCP Python SDK
- [x] I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue
### Description
Dynamic URL resource parameters in MCP protocol are not automatically URL-decoded, causing encoded characters (like %20 for spaces and %C3%A9 for accented characters) to be passed as-is to resource handlers instead of their decoded equivalents.
Here is a simple log for the bug:
- **before**
```
2025-06-17 14:43:44,385 [INFO] kn-graph: Found 0 products matching 'stick%20correcteur%20teint%C3%A9%20anti-imperfections%20rechargeable%20au%20zinc' - (logger.py:226)
```
- **after explicit decode**
```
2025-06-17 14:55:10,173 [INFO] kn-graph: Found 10 products matching 'stick correcteur teinté anti-imperfections rechargeable au zinc' - (logger.py:226)
```
### Example Code
```Python
@mcp.resource("products://search/{product_identifier}")
def find_similar_products(product_identifier: str):
"""
Find similar products based on a given product identifier.
:param product_identifier: The identifier of the product (product name or code).
:return: Similar products or an error message if none are found.
"""
print(product_identifier)
"""
-- walkaround: explicit decoding
from urllib.parse import unquote
print(unquote(product_identifier))
"""
```
### Python & MCP Python SDK
```Text
# uv pip list | grep "mcp"
mcp 1.9.2
# python --version
Python 3.13.4
```
## Task Budget (Session terminates when any budget is exhausted)
- Time allowance: 7.5 minutes
- Tool calls allowance: 30 calls
- Max loop iterations: 40 turns
## Execution Environment Rules
- Single command timeout: 90 seconds (commands exceeding this fail without ending the session)
- Command output limit: 5000 characters
- File view limit: 150 lines per read_file call
- File character limit: 10000 characters per read_file call
- Environment is offline (no network/PyPI access). All repository and test dependencies are ALREADY pre-installed. Do NOT attempt to run pip install or download packages.
## Instructions:
0. All source code is under `/workspace`. Do NOT search outside `/workspace` (e.g. `/usr/`, `/wheels/`, system site-packages). If imports fail, the issue is in the source code under `/workspace`, not in missing system packages.
1. Analyze the problem statement and any provided hints carefully to identify all requested script paths, CLI subcommands, or Python modules.
2. Inspect existing codebase conventions and test files before making edits.
3. Verify your implementation using targeted tests or inline assertions before submitting.
4. Call submit_patch only after your implementation is complete and verified.
5. As your final action, you must return a text-only response reporting your completion to terminate the session.
## Workspace Layout
The repository is located at `/workspace`. Here is the directory tree (up to 3 levels):
```
./CLAUDE.md
./CODE_OF_CONDUCT.md
./CONTRIBUTING.md
./LICENSE
./README.md
./RELEASE.md
./SECURITY.md
./docs
./examples
./mkdocs.yml
./pyproject.toml
./scripts
./scripts/test
./scripts/update_readme_snippets.py
./src
./src/mcp
./src/mcp/__init__.py
./src/mcp/cli
./src/mcp/client
./src/mcp/os
./src/mcp/py.typed
./src/mcp/server
./src/mcp/shared
./src/mcp/types.py
./tests
./uv.lock
```
Turn 1at 24 s224 tokens out3,031 prompt tokens
The user is reporting that dynamic resource parameters in the MCP Python SDK are not being URL-decoded before being passed to the resource handler.
For example, if a resource is defined as `products://search/{product_identifier}`, and the URL is `products://search/stick%20correcteur`, the `product_identifier` parameter received by the handler is `'stick%20correcteur'` instead of `'stick correcteur'`.
I need to find where the dynamic resource parameters are parsed and decoded.
Based on the workspace layout:
- `src/mcp/server` likely contains the logic for handling resources.
- `src/mcp/types.py` might define the data structures.
I'll start by searching for "resource" and "product_identifier" (or similar parameter extraction logic) in `src/mcp/server`.
TOOL CALL · run_command
{
"command": "grep -rn --include=\"*.py\" \"resource\" src/mcp/server | head -n 20"
}Result of run_command 2,678 characters
{
"status": "ok",
"stdout": "src/mcp/server/fastmcp/resources/templates.py:12:from mcp.server.fastmcp.resources.types import FunctionResource, Resource\nsrc/mcp/server/fastmcp/resources/templates.py:24: \"\"\"A template for dynamically creating resources.\"\"\"\nsrc/mcp/server/fastmcp/resources/templates.py:27: name: str = Field(description=\"Name of the resource\")\nsrc/mcp/server/fastmcp/resources/templates.py:28: title: str | None = Field(description=\"Human-readable title of the resource\", default=None)\nsrc/mcp/server/fastmcp/resources/templates.py:29: description: str | None = Field(description=\"Description of what the resource does\")\nsrc/mcp/server/fastmcp/resources/templates.py:30: mime_type: str = Field(default=\"text/plain\", description=\"MIME type of the resource content\")\nsrc/mcp/server/fastmcp/resources/templates.py:31: icons: list[Icon] | None = Field(default=None, description=\"Optional list of icons for the resource template\")\nsrc/mcp/server/fastmcp/resources/templates.py:32: annotations: Annotations | None = Field(default=None, description=\"Optional annotations for the resource template\")\nsrc/mcp/server/fastmcp/resources/templates.py:33: meta: dict[str, Any] | None = Field(default=None, description=\"Optional metadata for this resource template\")\nsrc/mcp/server/fastmcp/resources/templates.py:94: async def create_resource(\nsrc/mcp/server/fastmcp/resources/templates.py:100: \"\"\"Create a resource from the template with the given parameters.\"\"\"\nsrc/mcp/server/fastmcp/resources/templates.py:122: raise ValueError(f\"Error creating resource from template: {e}\")\nsrc/mcp/server/fastmcp/resources/base.py:1:\"\"\"Base classes and interfaces for FastMCP resources.\"\"\"\nsrc/mcp/server/fastmcp/resources/base.py:18: \"\"\"Base class for all resources.\"\"\"\nsrc/mcp/server/fastmcp/resources/base.py:22: uri: str = Field(default=..., description=\"URI of the resource\")\nsrc/mcp/server/fastmcp/resources/base.py:23: name: str | None = Field(description=\"Name of the resource\", default=None)\nsrc/mcp/server/fastmcp/resources/base.py:24: title: str | None = Field(description=\"Human-readable title of the resource\", default=None)\nsrc/mcp/server/fastmcp/resources/base.py:25: description: str | None = Field(description=\"Description of the resource\", default=None)\nsrc/mcp/server/fastmcp/resources/base.py:28: description=\"MIME type of the resource content\",\nsrc/mcp/server/fastmcp/resources/base.py:31: icons: list[Icon] | None = Field(default=None, description=\"Optional list of icons for this resource\")\n",
"stderr": "",
"exit_code": 0
}Generated tokens 224 tokens · stopped: STOP
<|channel>thought
The user is reporting that dynamic resource parameters in the MCP Python SDK are not being URL-decoded before being passed to the resource handler.
For example, if a resource is defined as `products://search/{product_identifier}`, and the URL is `products://search/stick%20correcteur`, the `product_identifier` parameter received by the handler is `'stick%20correcteur'` instead of `'stick correcteur'`.
I need to find where the dynamic resource parameters are parsed and decoded.
Based on the workspace layout:
- `src/mcp/server` likely contains the logic for handling resources.
- `src/mcp/types.py` might define the data structures.
I'll start by searching for "resource" and "product_identifier" (or similar parameter extraction logic) in `src/mcp/server`.<channel|><|tool_call>call:run_command{command:<|"|>grep -rn --include="*.py" "resource" src/mcp/server | head -n 20<|"|>}<tool_call|><|tool_response>
Turn 2at 37 s135 tokens out4,097 prompt tokens
The file `src/mcp/server/fastmcp/resources/templates.py` seems very relevant, especially `create_resource`.
Also, the example uses `@mcp.resource("products://search/{product_identifier}")`, which looks like a decorator. This is probably handled by `FastMCP`.
Let's search for where `@mcp.resource` is defined. It's probably in `src/mcp/server/fastmcp/server.py` or similar.
TOOL CALL · run_command
{
"command": "grep -rn \"def resource\" src/mcp/server"
}Result of run_command 116 characters
{
"status": "ok",
"stdout": "src/mcp/server/fastmcp/server.py:519: def resource(\n",
"stderr": "",
"exit_code": 0
}Generated tokens 135 tokens · stopped: STOP
The file `src/mcp/server/fastmcp/resources/templates.py` seems very relevant, especially `create_resource`.
Also, the example uses `@mcp.resource("products://search/{product_identifier}")`, which looks like a decorator. This is probably handled by `FastMCP`.
Let's search for where `@mcp.resource` is defined. It's probably in `src/mcp/server/fastmcp/server.py` or similar.
<channel|><|tool_call>call:run_command{command:<|"|>grep -rn "def resource" src/mcp/server<|"|>}<tool_call|><|tool_response>
Turn 3at 46 s132 tokens out4,294 prompt tokens
Okay, `@mcp.resource` is defined in `src/mcp/server/fastmcp/server.py`. Let's examine `src/mcp/server/fastmcp/server.py` around line 519 to see how resources are registered and how they are handled. I also want to see how `src/mcp/server/fastmcp/resources/templates.py` is used.
TOOL CALL · read_file
{
"filepath": "src/mcp/server/fastmcp/server.py",
"start_line": 519
}Result of read_file 6,033 characters
{
"status": "ok",
"filepath": "src/mcp/server/fastmcp/server.py",
"content": " def resource(\n self,\n uri: str,\n *,\n name: str | None = None,\n title: str | None = None,\n description: str | None = None,\n mime_type: str | None = None,\n icons: list[Icon] | None = None,\n annotations: Annotations | None = None,\n meta: dict[str, Any] | None = None,\n ) -> Callable[[AnyFunction], AnyFunction]:\n \"\"\"Decorator to register a function as a resource.\n\n The function will be called when the resource is read to generate its content.\n The function can return:\n - str for text content\n - bytes for binary content\n - other types will be converted to JSON\n\n If the URI contains parameters (e.g. \"resource://{param}\") or the function\n has parameters, it will be registered as a template resource.\n\n Args:\n uri: URI for the resource (e.g. \"resource://my-resource\" or \"resource://{param}\")\n name: Optional name for the resource\n title: Optional human-readable title for the resource\n description: Optional description of the resource\n mime_type: Optional MIME type for the resource\n meta: Optional metadata dictionary for the resource\n\n Example:\n @server.resource(\"resource://my-resource\")\n def get_data() -> str:\n return \"Hello, world!\"\n\n @server.resource(\"resource://my-resource\")\n async get_data() -> str:\n data = await fetch_data()\n return f\"Hello, world! {data}\"\n\n @server.resource(\"resource://{city}/weather\")\n def get_weather(city: str) -> str:\n return f\"Weather for {city}\"\n\n @server.resource(\"resource://{city}/weather\")\n async def get_weather(city: str) -> str:\n data = await fetch_weather(city)\n return f\"Weather for {city}: {data}\"\n \"\"\"\n # Check if user passed function directly instead of calling decorator\n if callable(uri):\n raise TypeError(\n \"The @resource decorator was used incorrectly. \"\n \"Did you forget to call it? Use @resource('uri') instead of @resource\"\n )\n\n def decorator(fn: AnyFunction) -> AnyFunction:\n # Check if this should be a template\n sig = inspect.signature(fn)\n has_uri_params = \"{\" in uri and \"}\" in uri\n has_func_params = bool(sig.parameters)\n\n if has_uri_params or has_func_params:\n # Check for Context parameter to exclude from validation\n context_param = find_context_parameter(fn)\n\n # Validate that URI params match function params (excluding context)\n uri_params = set(re.findall(r\"{(\\w+)}\", uri))\n # We need to remove the context_param from the resource function if\n # there is any.\n func_params = {p for p in sig.parameters.keys() if p != context_param}\n\n if uri_params != func_params:\n raise ValueError(\n f\"Mismatch between URI parameters {uri_params} and function parameters {func_params}\"\n )\n\n # Register as template\n self._resource_manager.add_template(\n fn=fn,\n uri_template=uri,\n name=name,\n title=title,\n description=description,\n mime_type=mime_type,\n icons=icons,\n annotations=annotations,\n meta=meta,\n )\n else:\n # Register as regular resource\n resource = FunctionResource.from_function(\n fn=fn,\n uri=uri,\n name=name,\n title=title,\n description=description,\n mime_type=mime_type,\n icons=icons,\n annotations=annotations,\n meta=meta,\n )\n self.add_resource(resource)\n return fn\n\n return decorator\n\n def add_prompt(self, prompt: Prompt) -> None:\n \"\"\"Add a prompt to the server.\n\n Args:\n prompt: A Prompt instance to add\n \"\"\"\n self._prompt_manager.add_prompt(prompt)\n\n def prompt(\n self,\n name: str | None = None,\n title: str | None = None,\n description: str | None = None,\n icons: list[Icon] | None = None,\n ) -> Callable[[AnyFunction], AnyFunction]:\n \"\"\"Decorator to register a prompt.\n\n Args:\n name: Optional name for the prompt (defaults to function name)\n title: Optional human-readable title for the prompt\n description: Optional description of what the prompt does\n\n Example:\n @server.prompt()\n def analyze_table(table_name: str) -> list[Message]:\n schema = read_table_schema(table_name)\n return [\n {\n \"role\": \"user\",\n \"content\": f\"Analyze this schema:\\n{schema}\"\n }\n ]\n\n @server.prompt()\n async def analyze_file(path: str) -> list[Message]:\n content = await read_file(path)\n return [\n {\n \"role\": \"user\",\n \"content\": {\n \"type\": \"resource\",\n \"resource\": {",
"start_line": 519,
"end_line": 668,
"total_lines": 1298,
"is_truncated": true
}Generated tokens 132 tokens · stopped: STOP
Okay, `@mcp.resource` is defined in `src/mcp/server/fastmcp/server.py`.
Let's examine `src/mcp/server/fastmcp/server.py` around line 519 to see how resources are registered and how they are handled.
I also want to see how `src/mcp/server/fastmcp/resources/templates.py` is used.
<channel|><|tool_call>call:read_file{filepath:<|"|>src/mcp/server/fastmcp/server.py<|"|>,start_line:519}<tool_call|><|tool_response>
Turn 4at 54 s112 tokens out5,857 prompt tokens
The `resource` decorator calls `self._resource_manager.add_template`. I need to see how `self._resource_manager` is implemented and how it handles requests for resources. Let's find the `ResourceManager` class. It's likely in `src/mcp/server/fastmcp/resources/manager.py` or something similar.
TOOL CALL · run_command
{
"command": "find src/mcp/server/fastmcp/resources -name \"*.py\""
}Result of run_command 292 characters
{
"status": "ok",
"stdout": "src/mcp/server/fastmcp/resources/templates.py\nsrc/mcp/server/fastmcp/resources/base.py\nsrc/mcp/server/fastmcp/resources/types.py\nsrc/mcp/server/fastmcp/resources/__init__.py\nsrc/mcp/server/fastmcp/resources/resource_manager.py\n",
"stderr": "",
"exit_code": 0
}Generated tokens 112 tokens · stopped: STOP
The `resource` decorator calls `self._resource_manager.add_template`.
I need to see how `self._resource_manager` is implemented and how it handles requests for resources.
Let's find the `ResourceManager` class. It's likely in `src/mcp/server/fastmcp/resources/manager.py` or something similar.
<channel|><|tool_call>call:run_command{command:<|"|>find src/mcp/server/fastmcp/resources -name "*.py"<|"|>}<tool_call|><|tool_response>
Turn 5at 58 s63 tokens out6,099 prompt tokens
It's `src/mcp/server/fastmcp/resources/resource_manager.py`. Let's read it.
TOOL CALL · read_file
{
"filepath": "src/mcp/server/fastmcp/resources/resource_manager.py"
}Result of read_file 4,364 characters
{
"status": "ok",
"filepath": "src/mcp/server/fastmcp/resources/resource_manager.py",
"content": "\"\"\"Resource manager functionality.\"\"\"\n\nfrom __future__ import annotations\n\nfrom collections.abc import Callable\nfrom typing import TYPE_CHECKING, Any\n\nfrom pydantic import AnyUrl\n\nfrom mcp.server.fastmcp.resources.base import Resource\nfrom mcp.server.fastmcp.resources.templates import ResourceTemplate\nfrom mcp.server.fastmcp.utilities.logging import get_logger\nfrom mcp.types import Annotations, Icon\n\nif TYPE_CHECKING:\n from mcp.server.fastmcp.server import Context\n from mcp.server.session import ServerSessionT\n from mcp.shared.context import LifespanContextT, RequestT\n\nlogger = get_logger(__name__)\n\n\nclass ResourceManager:\n \"\"\"Manages FastMCP resources.\"\"\"\n\n def __init__(self, warn_on_duplicate_resources: bool = True):\n self._resources: dict[str, Resource] = {}\n self._templates: dict[str, ResourceTemplate] = {}\n self.warn_on_duplicate_resources = warn_on_duplicate_resources\n\n def add_resource(self, resource: Resource) -> Resource:\n \"\"\"Add a resource to the manager.\n\n Args:\n resource: A Resource instance to add\n\n Returns:\n The added resource. If a resource with the same URI already exists,\n returns the existing resource.\n \"\"\"\n logger.debug(\n \"Adding resource\",\n extra={\n \"uri\": resource.uri,\n \"type\": type(resource).__name__,\n \"resource_name\": resource.name,\n },\n )\n existing = self._resources.get(str(resource.uri))\n if existing:\n if self.warn_on_duplicate_resources:\n logger.warning(f\"Resource already exists: {resource.uri}\")\n return existing\n self._resources[str(resource.uri)] = resource\n return resource\n\n def add_template(\n self,\n fn: Callable[..., Any],\n uri_template: str,\n name: str | None = None,\n title: str | None = None,\n description: str | None = None,\n mime_type: str | None = None,\n icons: list[Icon] | None = None,\n annotations: Annotations | None = None,\n meta: dict[str, Any] | None = None,\n ) -> ResourceTemplate:\n \"\"\"Add a template from a function.\"\"\"\n template = ResourceTemplate.from_function(\n fn,\n uri_template=uri_template,\n name=name,\n title=title,\n description=description,\n mime_type=mime_type,\n icons=icons,\n annotations=annotations,\n meta=meta,\n )\n self._templates[template.uri_template] = template\n return template\n\n async def get_resource(\n self,\n uri: AnyUrl | str,\n context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None,\n ) -> Resource | None:\n \"\"\"Get resource by URI, checking concrete resources first, then templates.\"\"\"\n uri_str = str(uri)\n logger.debug(\"Getting resource\", extra={\"uri\": uri_str})\n\n # First check concrete resources\n if resource := self._resources.get(uri_str):\n return resource\n\n # Then check templates\n for template in self._templates.values():\n if params := template.matches(uri_str):\n try:\n return await template.create_resource(uri_str, params, context=context)\n except Exception as e: # pragma: no cover\n raise ValueError(f\"Error creating resource from template: {e}\")\n\n raise ValueError(f\"Unknown resource: {uri}\")\n\n def list_resources(self) -> list[Resource]:\n \"\"\"List all registered resources.\"\"\"\n logger.debug(\"Listing resources\", extra={\"count\": len(self._resources)})\n return list(self._resources.values())\n\n def list_templates(self) -> list[ResourceTemplate]:\n \"\"\"List all registered templates.\"\"\"\n logger.debug(\"Listing templates\", extra={\"count\": len(self._templates)})\n return list(self._templates.values())",
"start_line": 1,
"end_line": 115,
"total_lines": 115,
"is_truncated": false
}Generated tokens 63 tokens · stopped: STOP
It's `src/mcp/server/fastmcp/resources/resource_manager.py`. Let's read it.
<channel|><|tool_call>call:read_file{filepath:<|"|>src/mcp/server/fastmcp/resources/resource_manager.py<|"|>}<tool_call|><|tool_response>
Turn 6at 68 s149 tokens out7,333 prompt tokens
In `ResourceManager.get_resource`:
```python
# Then check templates
for template in self._templates.values():
if params := template.matches(uri_str):
try:
return await template.create_resource(uri_str, params, context=context)
```
`template.matches(uri_str)` extracts the parameters, and then `template.create_resource` is called.
Let's look at `src/mcp/server/fastmcp/resources/templates.py`.
TOOL CALL · read_file
{
"filepath": "src/mcp/server/fastmcp/resources/templates.py"
}Result of read_file 5,308 characters
{
"status": "ok",
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"content": "\"\"\"Resource template functionality.\"\"\"\n\nfrom __future__ import annotations\n\nimport inspect\nimport re\nfrom collections.abc import Callable\nfrom typing import TYPE_CHECKING, Any\n\nfrom pydantic import BaseModel, Field, validate_call\n\nfrom mcp.server.fastmcp.resources.types import FunctionResource, Resource\nfrom mcp.server.fastmcp.utilities.context_injection import find_context_parameter, inject_context\nfrom mcp.server.fastmcp.utilities.func_metadata import func_metadata\nfrom mcp.types import Annotations, Icon\n\nif TYPE_CHECKING:\n from mcp.server.fastmcp.server import Context\n from mcp.server.session import ServerSessionT\n from mcp.shared.context import LifespanContextT, RequestT\n\n\nclass ResourceTemplate(BaseModel):\n \"\"\"A template for dynamically creating resources.\"\"\"\n\n uri_template: str = Field(description=\"URI template with parameters (e.g. weather://{city}/current)\")\n name: str = Field(description=\"Name of the resource\")\n title: str | None = Field(description=\"Human-readable title of the resource\", default=None)\n description: str | None = Field(description=\"Description of what the resource does\")\n mime_type: str = Field(default=\"text/plain\", description=\"MIME type of the resource content\")\n icons: list[Icon] | None = Field(default=None, description=\"Optional list of icons for the resource template\")\n annotations: Annotations | None = Field(default=None, description=\"Optional annotations for the resource template\")\n meta: dict[str, Any] | None = Field(default=None, description=\"Optional metadata for this resource template\")\n fn: Callable[..., Any] = Field(exclude=True)\n parameters: dict[str, Any] = Field(description=\"JSON schema for function parameters\")\n context_kwarg: str | None = Field(None, description=\"Name of the kwarg that should receive context\")\n\n @classmethod\n def from_function(\n cls,\n fn: Callable[..., Any],\n uri_template: str,\n name: str | None = None,\n title: str | None = None,\n description: str | None = None,\n mime_type: str | None = None,\n icons: list[Icon] | None = None,\n annotations: Annotations | None = None,\n meta: dict[str, Any] | None = None,\n context_kwarg: str | None = None,\n ) -> ResourceTemplate:\n \"\"\"Create a template from a function.\"\"\"\n func_name = name or fn.__name__\n if func_name == \"<lambda>\":\n raise ValueError(\"You must provide a name for lambda functions\") # pragma: no cover\n\n # Find context parameter if it exists\n if context_kwarg is None: # pragma: no branch\n context_kwarg = find_context_parameter(fn)\n\n # Get schema from func_metadata, excluding context parameter\n func_arg_metadata = func_metadata(\n fn,\n skip_names=[context_kwarg] if context_kwarg is not None else [],\n )\n parameters = func_arg_metadata.arg_model.model_json_schema()\n\n # ensure the arguments are properly cast\n fn = validate_call(fn)\n\n return cls(\n uri_template=uri_template,\n name=func_name,\n title=title,\n description=description or fn.__doc__ or \"\",\n mime_type=mime_type or \"text/plain\",\n icons=icons,\n annotations=annotations,\n meta=meta,\n fn=fn,\n parameters=parameters,\n context_kwarg=context_kwarg,\n )\n\n def matches(self, uri: str) -> dict[str, Any] | None:\n \"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n return match.groupdict()\n return None\n\n async def create_resource(\n self,\n uri: str,\n params: dict[str, Any],\n context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None,\n ) -> Resource:\n \"\"\"Create a resource from the template with the given parameters.\"\"\"\n try:\n # Add context to params if needed\n params = inject_context(self.fn, params, context, self.context_kwarg)\n\n # Call function and check if result is a coroutine\n result = self.fn(**params)\n if inspect.iscoroutine(result):\n result = await result\n\n return FunctionResource(\n uri=uri, # type: ignore\n name=self.name,\n title=self.title,\n description=self.description,\n mime_type=self.mime_type,\n icons=self.icons,\n annotations=self.annotations,\n meta=self.meta,\n fn=lambda: result, # Capture result in closure\n )\n except Exception as e:\n raise ValueError(f\"Error creating resource from template: {e}\")",
"start_line": 1,
"end_line": 122,
"total_lines": 122,
"is_truncated": false
}Generated tokens 149 tokens · stopped: STOP
In `ResourceManager.get_resource`:
```python
# Then check templates
for template in self._templates.values():
if params := template.matches(uri_str):
try:
return await template.create_resource(uri_str, params, context=context)
```
`template.matches(uri_str)` extracts the parameters, and then `template.create_resource` is called.
Let's look at `src/mcp/server/fastmcp/resources/templates.py`.
<channel|><|tool_call>call:read_file{filepath:<|"|>src/mcp/server/fastmcp/resources/templates.py<|"|>}<tool_call|><|tool_response>
Turn 7at 92 s453 tokens out8,906 prompt tokens
The `matches` method extracts parameters using regex:
```python
def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n return match.groupdict()\n return None
```
The `groupdict()` returns the extracted values exactly as they appear in the URI. If the URI is `products://search/stick%20correcteur`, and the template is `products://search/{product_identifier}`, then `params` will be `{'product_identifier': 'stick%20correcteur'}`.
Then in `create_resource`, these params are passed to `self.fn(**params)`.
```python
async def create_resource(
self,
uri: str,
params: dict[str, Any],
context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None,
) -> Resource:
- \"\"\"Create a resource from the template with the given parameters.\"\"\"\n try:
# Add context to params if needed
params = inject_context(self.fn, params, context, self.context_kwarg)
# Call function and check if result is a coroutine
result = self.fn(**params)
```
I should decode the parameters in `matches` or `create_resource`. URL decoding is typically done using `urllib.parse.unquote`.
Let's verify this with a reproduction test.
I'll create a test file that simulates the reported issue.
Wait, I should check if there are any existing tests for resource templates.
TOOL CALL · run_command
{
"command": "find tests -name \"*resource*\""
}Result of run_command 678 characters
{
"status": "ok",
"stdout": "tests/server/fastmcp/resources\ntests/server/fastmcp/resources/test_file_resources.py\ntests/server/fastmcp/resources/test_function_resources.py\ntests/server/fastmcp/resources/test_resource_manager.py\ntests/server/fastmcp/resources/test_resources.py\ntests/server/fastmcp/resources/test_resource_template.py\ntests/server/auth/test_protected_resource.py\ntests/server/test_read_resource.py\ntests/issues/test_152_resource_mime_type.py\ntests/issues/test_1574_resource_uri_validation.py\ntests/issues/test_129_resource_templates.py\ntests/issues/test_141_resource_templates.py\ntests/client/test_resource_cleanup.py\n",
"stderr": "",
"exit_code": 0
}Generated tokens 453 tokens · stopped: STOP
The `matches` method extracts parameters using regex:
```python
def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n return match.groupdict()\n return None
```
The `groupdict()` returns the extracted values exactly as they appear in the URI. If the URI is `products://search/stick%20correcteur`, and the template is `products://search/{product_identifier}`, then `params` will be `{'product_identifier': 'stick%20correcteur'}`.
Then in `create_resource`, these params are passed to `self.fn(**params)`.
```python
async def create_resource(
self,
uri: str,
params: dict[str, Any],
context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None,
) -> Resource:
- \"\"\"Create a resource from the template with the given parameters.\"\"\"\n try:
# Add context to params if needed
params = inject_context(self.fn, params, context, self.context_kwarg)
# Call function and check if result is a coroutine
result = self.fn(**params)
```
I should decode the parameters in `matches` or `create_resource`. URL decoding is typically done using `urllib.parse.unquote`.
Let's verify this with a reproduction test.
I'll create a test file that simulates the reported issue.
Wait, I should check if there are any existing tests for resource templates.
<channel|><|tool_call>call:run_command{command:<|"|>find tests -name "*resource*"<|"|>}<tool_call|><|tool_response>
Turn 8at 99 s75 tokens out9,615 prompt tokens
`tests/server/fastmcp/resources/test_resource_template.py` seems like the best place. Let's read it to see if I can add a test case there.
TOOL CALL · read_file
{
"filepath": "tests/server/fastmcp/resources/test_resource_template.py"
}Result of read_file 5,069 characters
{
"status": "ok",
"filepath": "tests/server/fastmcp/resources/test_resource_template.py",
"content": "import json\nfrom typing import Any\n\nimport pytest\nfrom pydantic import BaseModel\n\nfrom mcp.server.fastmcp import FastMCP\nfrom mcp.server.fastmcp.resources import FunctionResource, ResourceTemplate\nfrom mcp.types import Annotations\n\n\nclass TestResourceTemplate:\n \"\"\"Test ResourceTemplate functionality.\"\"\"\n\n def test_template_creation(self):\n \"\"\"Test creating a template from a function.\"\"\"\n\n def my_func(key: str, value: int) -> dict[str, Any]: # pragma: no cover\n return {\"key\": key, \"value\": value}\n\n template = ResourceTemplate.from_function(\n fn=my_func,\n uri_template=\"test://{key}/{value}\",\n name=\"test\",\n )\n assert template.uri_template == \"test://{key}/{value}\"\n assert template.name == \"test\"\n assert template.mime_type == \"text/plain\" # default\n assert template.fn(key=\"test\", value=42) == my_func(key=\"test\", value=42)\n\n def test_template_matches(self):\n \"\"\"Test matching URIs against a template.\"\"\"\n\n def my_func(key: str, value: int) -> dict[str, Any]: # pragma: no cover\n return {\"key\": key, \"value\": value}\n\n template = ResourceTemplate.from_function(\n fn=my_func,\n uri_template=\"test://{key}/{value}\",\n name=\"test\",\n )\n\n # Valid match\n params = template.matches(\"test://foo/123\")\n assert params == {\"key\": \"foo\", \"value\": \"123\"}\n\n # No match\n assert template.matches(\"test://foo\") is None\n assert template.matches(\"other://foo/123\") is None\n\n @pytest.mark.anyio\n async def test_create_resource(self):\n \"\"\"Test creating a resource from a template.\"\"\"\n\n def my_func(key: str, value: int) -> dict[str, Any]:\n return {\"key\": key, \"value\": value}\n\n template = ResourceTemplate.from_function(\n fn=my_func,\n uri_template=\"test://{key}/{value}\",\n name=\"test\",\n )\n\n resource = await template.create_resource(\n \"test://foo/123\",\n {\"key\": \"foo\", \"value\": 123},\n )\n\n assert isinstance(resource, FunctionResource)\n content = await resource.read()\n assert isinstance(content, str)\n data = json.loads(content)\n assert data == {\"key\": \"foo\", \"value\": 123}\n\n @pytest.mark.anyio\n async def test_template_error(self):\n \"\"\"Test error handling in template resource creation.\"\"\"\n\n def failing_func(x: str) -> str:\n raise ValueError(\"Test error\")\n\n template = ResourceTemplate.from_function(\n fn=failing_func,\n uri_template=\"fail://{x}\",\n name=\"fail\",\n )\n\n with pytest.raises(ValueError, match=\"Error creating resource from template\"):\n await template.create_resource(\"fail://test\", {\"x\": \"test\"})\n\n @pytest.mark.anyio\n async def test_async_text_resource(self):\n \"\"\"Test creating a text resource from async function.\"\"\"\n\n async def greet(name: str) -> str:\n return f\"Hello, {name}!\"\n\n template = ResourceTemplate.from_function(\n fn=greet,\n uri_template=\"greet://{name}\",\n name=\"greeter\",\n )\n\n resource = await template.create_resource(\n \"greet://world\",\n {\"name\": \"world\"},\n )\n\n assert isinstance(resource, FunctionResource)\n content = await resource.read()\n assert content == \"Hello, world!\"\n\n @pytest.mark.anyio\n async def test_async_binary_resource(self):\n \"\"\"Test creating a binary resource from async function.\"\"\"\n\n async def get_bytes(value: str) -> bytes:\n return value.encode()\n\n template = ResourceTemplate.from_function(\n fn=get_bytes,\n uri_template=\"bytes://{value}\",\n name=\"bytes\",\n )\n\n resource = await template.create_resource(\n \"bytes://test\",\n {\"value\": \"test\"},\n )\n\n assert isinstance(resource, FunctionResource)\n content = await resource.read()\n assert content == b\"test\"\n\n @pytest.mark.anyio\n async def test_basemodel_conversion(self):\n \"\"\"Test handling of BaseModel types.\"\"\"\n\n class MyModel(BaseModel):\n key: str\n value: int\n\n def get_data(key: str, value: int) -> MyModel:\n return MyModel(key=key, value=value)\n\n template = ResourceTemplate.from_function(\n fn=get_data,\n uri_template=\"test://{key}/{value}\",\n name=\"test\",\n )",
"start_line": 1,
"end_line": 150,
"total_lines": 307,
"is_truncated": true
}Generated tokens 75 tokens · stopped: STOP
`tests/server/fastmcp/resources/test_resource_template.py` seems like the best place.
Let's read it to see if I can add a test case there.
<channel|><|tool_call>call:read_file{filepath:<|"|>tests/server/fastmcp/resources/test_resource_template.py<|"|>}<tool_call|><|tool_response>
Turn 9at 127 s386 tokens out11,139 prompt tokens
I'll create a reproduction script using `pytest` to demonstrate the failure. Specifically, I want to see that `template.matches` returns encoded strings, and that `template.create_resource` passes those encoded strings to the function.
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport pytest\nfrom mcp.server.fastmcp.resources.templates import ResourceTemplate\n\ndef test_resource_template_decoding():\n def my_func(product_identifier: str):\n return product_identifier\n\n template = ResourceTemplate.from_function(\n fn=my_func,\n uri_template=\"products://search/{product_identifier}\",\n name=\"products\",\n )\n\n # This is the case reported in the issue\n uri = \"products://search/stick%20correcteur%20teint%C3%A9%20anti-imperfections\"\n params = template.matches(uri)\n print(f\"Extracted params: {params}\")\n \n # We expect the 'product_identifier' to be decoded\n # 'stick correcteur teinté anti-imperfections'\n \n import asyncio\n async def run():\n resource = await template.create_resource(uri, params)\n content = await resource.read()\n print(f\"Resource content: {content}\")\n assert content == \"stick correcteur teinté anti-imperfections\"\n\n try:\n asyncio.run(run())\n except Exception as e:\n print(f\"Caught exception: {e}\")\n raise e\n\nif __name__ == \"__main__\":\n test_resource_template_decoding()\nPY\n"
}Result of run_command 1,827 characters
{
"status": "error",
"error_type": "CommandError",
"error_message": "Traceback (most recent call last):\n File \"<stdin>\", line 36, in <module>\n File \"<stdin>\", line 33, in test_resource_template_decoding\n File \"<stdin>\", line 30, in test_resource_template_decoding\n File \"/opt/conda/envs/testbed/lib/python3.12/asyncio/runners.py\", line 195, in run\n return runner.run(main)\n ^^^^^^^^^^^^^^^^\n File \"/opt/conda/envs/testbed/lib/python3.12/asyncio/runners.py\", line 118, in run\n return self._loop.run_until_complete(task)\n ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n File \"/opt/conda/envs/testbed/lib/python3.12/asyncio/base_events.py\", line 691, in run_until_complete\n return future.result()\n ^^^^^^^^^^^^^^^\n File \"<stdin>\", line 27, in run\nAssertionError\n",
"details": {
"stdout": "Extracted params: {'product_identifier': 'stick%20correcteur%20teint%C3%A9%20anti-imperfections'}\nResource content: stick%20correcteur%20teint%C3%A9%20anti-imperfections\nCaught exception: \n",
"stderr": "Traceback (most recent call last):\n File \"<stdin>\", line 36, in <module>\n File \"<stdin>\", line 33, in test_resource_template_decoding\n File \"<stdin>\", line 30, in test_resource_template_decoding\n File \"/opt/conda/envs/testbed/lib/python3.12/asyncio/runners.py\", line 195, in run\n return runner.run(main)\n ^^^^^^^^^^^^^^^^\n File \"/opt/conda/envs/testbed/lib/python3.12/asyncio/runners.py\", line 118, in run\n return self._loop.run_until_complete(task)\n ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n File \"/opt/conda/envs/testbed/lib/python3.12/asyncio/base_events.py\", line 691, in run_until_complete\n return future.result()\n ^^^^^^^^^^^^^^^\n File \"<stdin>\", line 27, in run\nAssertionError\n",
"exit_code": 1
}
}Generated tokens 386 tokens · stopped: STOP
I'll create a reproduction script using `pytest` to demonstrate the failure.
Specifically, I want to see that `template.matches` returns encoded strings, and that `template.create_resource` passes those encoded strings to the function.
<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import pytest
from mcp.server.fastmcp.resources.templates import ResourceTemplate
def test_resource_template_decoding():
def my_func(product_identifier: str):
return product_identifier
template = ResourceTemplate.from_function(
fn=my_func,
uri_template="products://search/{product_identifier}",
name="products",
)
# This is the case reported in the issue
uri = "products://search/stick%20correcteur%20teint%C3%A9%20anti-imperfections"
params = template.matches(uri)
print(f"Extracted params: {params}")
# We expect the 'product_identifier' to be decoded
# 'stick correcteur teinté anti-imperfections'
import asyncio
async def run():
resource = await template.create_resource(uri, params)
content = await resource.read()
print(f"Resource content: {content}")
assert content == "stick correcteur teinté anti-imperfections"
try:
asyncio.run(run())
except Exception as e:
print(f"Caught exception: {e}")
raise e
if __name__ == "__main__":
test_resource_template_decoding()
PY
<|"|>}<tool_call|><|tool_response>
Turn 10at 168 s727 tokens out12,194 prompt tokens
The reproduction confirms the bug.
`Extracted params: {'product_identifier': 'stick%20correcteur%20teint%C3%A9%20anti-imperfections'}`
`Resource content: stick%20correcteur%20teint%C3%A9%20anti-imperfections`
Now I need to fix this. The best place to fix it is in `ResourceTemplate.matches` so that all call sites of `matches` (like `ResourceManager.get_resource`) get the decoded parameters.
Wait, if I decode in `matches`, then `template.create_resource` will receive decoded parameters.
Let's look at `ResourceTemplate.matches` again.
```python
def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n return match.groupdict()\n return None
```
I can change it to:
```python
def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n from urllib.parse import unquote\n return {k: unquote(v) for k, v in match.groupdict().items()}\n return None
```
Wait, should I use `unquote` or `unquote_plus`?
Standard URL parameters use `%20` for space. `unquote` handles this. `unquote_plus` also handles `+` as space.
Given the example `stick%20correcteur`, `unquote` is correct.
Usually, for path segments, `unquote` is used. For query strings, `unquote_plus` is often used.
Since these are resources (URIs), they are path segments mostly.
Let's check if there's any reason NOT to decode here.
If the user specifically wanted the encoded string, they are out of luck, but this is the expected behavior for URL parameters in most frameworks.
Let's implement the fix in `src/mcp/server/fastmcp/resources/templates.py`.
I should also make sure I import `unquote` at the top of the file instead of inside the method for better performance and cleaner code.
Actually, if I import it at the top:
`from urllib.parse import unquote`
Let's check imports in `src/mcp/server/fastmcp/resources/templates.py`.
TOOL CALL · read_file
{
"end_line": 20,
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"start_line": 1
}Result of read_file 885 characters
{
"status": "ok",
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"content": "\"\"\"Resource template functionality.\"\"\"\n\nfrom __future__ import annotations\n\nimport inspect\nimport re\nfrom collections.abc import Callable\nfrom typing import TYPE_CHECKING, Any\n\nfrom pydantic import BaseModel, Field, validate_call\n\nfrom mcp.server.fastmcp.resources.types import FunctionResource, Resource\nfrom mcp.server.fastmcp.utilities.context_injection import find_context_parameter, inject_context\nfrom mcp.server.fastmcp.utilities.func_metadata import func_metadata\nfrom mcp.types import Annotations, Icon\n\nif TYPE_CHECKING:\n from mcp.server.fastmcp.server import Context\n from mcp.server.session import ServerSessionT\n from mcp.shared.context import LifespanContextT, RequestT",
"start_line": 1,
"end_line": 20,
"total_lines": 122,
"is_truncated": false
}Generated tokens 727 tokens · stopped: STOP
The reproduction confirms the bug.
`Extracted params: {'product_identifier': 'stick%20correcteur%20teint%C3%A9%20anti-imperfections'}`
`Resource content: stick%20correcteur%20teint%C3%A9%20anti-imperfections`
Now I need to fix this. The best place to fix it is in `ResourceTemplate.matches` so that all call sites of `matches` (like `ResourceManager.get_resource`) get the decoded parameters.
Wait, if I decode in `matches`, then `template.create_resource` will receive decoded parameters.
Let's look at `ResourceTemplate.matches` again.
```python
def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n return match.groupdict()\n return None
```
I can change it to:
```python
def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n from urllib.parse import unquote\n return {k: unquote(v) for k, v in match.groupdict().items()}\n return None
```
Wait, should I use `unquote` or `unquote_plus`?
Standard URL parameters use `%20` for space. `unquote` handles this. `unquote_plus` also handles `+` as space.
Given the example `stick%20correcteur`, `unquote` is correct.
Usually, for path segments, `unquote` is used. For query strings, `unquote_plus` is often used.
Since these are resources (URIs), they are path segments mostly.
Let's check if there's any reason NOT to decode here.
If the user specifically wanted the encoded string, they are out of luck, but this is the expected behavior for URL parameters in most frameworks.
Let's implement the fix in `src/mcp/server/fastmcp/resources/templates.py`.
I should also make sure I import `unquote` at the top of the file instead of inside the method for better performance and cleaner code.
Actually, if I import it at the top:
`from urllib.parse import unquote`
Let's check imports in `src/mcp/server/fastmcp/resources/templates.py`.
<channel|><|tool_call>call:read_file{filepath:<|"|>src/mcp/server/fastmcp/resources/templates.py<|"|>,start_line:1,end_line:20}<tool_call|><|tool_response>
Turn 11at 190 s412 tokens out13,204 prompt tokens
I will add `from urllib.parse import unquote` and update `matches`.
Wait, I should also verify if this affects anything else.
`ResourceTemplate.matches` is used in `ResourceManager.get_resource`:
```python
# Then check templates
for template in self._templates.values():
if params := template.matches(uri_str):
try:
return await template.create_resource(uri_str, params, context=context)
```
And `template.create_resource` uses `params`.
```python
async def create_resource(
self,
uri: str,
params: dict[str, Any],
context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None,
) -> Resource:
\"\"\"Create a resource from the template with the given parameters.\"\"\"\n try:
# Add context to params if needed
params = inject_context(self.fn, params, context, self.context_kwarg)
# Call function and check if result is a coroutine
result = self.fn(**params)
```
If `params` are decoded, `self.fn` receives decoded values. This is exactly what is requested.
One more thing: `ResourceTemplate.create_resource` is a public method. If someone calls it directly with their own `params` dict, they are responsible for decoding. That's fine.
Let's apply the fix.
TOOL CALL · edit_file
{
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"new_string": "import inspect\nimport re\nfrom urllib.parse import unquote\nfrom collections.abc import Callable\n",
"old_string": "import inspect\nimport re\nfrom collections.abc import Callable\n"
}Result of edit_file 423 characters
{
"status": "ok",
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"occurrences": 1,
"strategy": "exact",
"diff": "--- a/src/mcp/server/fastmcp/resources/templates.py\n+++ b/src/mcp/server/fastmcp/resources/templates.py\n@@ -4,6 +4,7 @@\n \n import inspect\n import re\n+from urllib.parse import unquote\n from collections.abc import Callable\n from typing import TYPE_CHECKING, Any\n \n",
"is_truncated": false
}Generated tokens 412 tokens · stopped: STOP
I will add `from urllib.parse import unquote` and update `matches`.
Wait, I should also verify if this affects anything else.
`ResourceTemplate.matches` is used in `ResourceManager.get_resource`:
```python
# Then check templates
for template in self._templates.values():
if params := template.matches(uri_str):
try:
return await template.create_resource(uri_str, params, context=context)
```
And `template.create_resource` uses `params`.
```python
async def create_resource(
self,
uri: str,
params: dict[str, Any],
context: Context[ServerSessionT, LifespanContextT, RequestT] | None = None,
) -> Resource:
\"\"\"Create a resource from the template with the given parameters.\"\"\"\n try:
# Add context to params if needed
params = inject_context(self.fn, params, context, self.context_kwarg)
# Call function and check if result is a coroutine
result = self.fn(**params)
```
If `params` are decoded, `self.fn` receives decoded values. This is exactly what is requested.
One more thing: `ResourceTemplate.create_resource` is a public method. If someone calls it directly with their own `params` dict, they are responsible for decoding. That's fine.
Let's apply the fix.<channel|><|tool_call>call:edit_file{filepath:<|"|>src/mcp/server/fastmcp/resources/templates.py<|"|>,new_string:<|"|>import inspect
import re
from urllib.parse import unquote
from collections.abc import Callable
<|"|>,old_string:<|"|>import inspect
import re
from collections.abc import Callable
<|"|>}<tool_call|><|tool_response>
Turn 12at 204 s286 tokens out13,779 prompt tokens
Now update `matches`.
TOOL CALL · edit_file
{
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"new_string": " def matches(self, uri: str) -> dict[str, Any] | None:\n \\\"\\\"\\\"Check if URI matches template and extract parameters.\\\"\\\"\\\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\\\"{\\\", \\\"(?P<\\\").replace(\\\"}\\\", \\\">[^/]+)\\\")\n match = re.match(f\\\"^{pattern}$\\\", uri)\n if match:\n return {k: unquote(v) for k, v in match.groupdict().items()}\n return None\n",
"old_string": " def matches(self, uri: str) -> dict[str, Any] | None:\n \\\"\\\"\\\"Check if URI matches template and extract parameters.\\\"\\\"\\\"\n # Convert template to regex pattern\n pattern = self.uri_template.replace(\\\"{\\\", \\\"(?P<\\\").replace(\\\"}\\\", \\\">[^/]+)\\\")\n match = re.match(f\\\"^{pattern}$\\\", uri)\n if match:\n return match.groupdict()\n return None\n"
}Result of edit_file 613 characters
{
"status": "ok",
"filepath": "src/mcp/server/fastmcp/resources/templates.py",
"occurrences": 1,
"strategy": "unescaped",
"diff": "--- a/src/mcp/server/fastmcp/resources/templates.py\n+++ b/src/mcp/server/fastmcp/resources/templates.py\n@@ -89,7 +89,7 @@\n pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")\n match = re.match(f\"^{pattern}$\", uri)\n if match:\n- return match.groupdict()\n+ return {k: unquote(v) for k, v in match.groupdict().items()}\n return None\n \n async def create_resource(\n",
"is_truncated": false
}Generated tokens 286 tokens · stopped: STOP
Now update `matches`.
<channel|><|tool_call>call:edit_file{filepath:<|"|>src/mcp/server/fastmcp/resources/templates.py<|"|>,new_string:<|"|> def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"
# Convert template to regex pattern
pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")
match = re.match(f\"^{pattern}$\", uri)
if match:
return {k: unquote(v) for k, v in match.groupdict().items()}
return None
<|"|>,old_string:<|"|> def matches(self, uri: str) -> dict[str, Any] | None:
\"\"\"Check if URI matches template and extract parameters.\"\"\"
# Convert template to regex pattern
pattern = self.uri_template.replace(\"{\", \"(?P<\").replace(\"}\", \">[^/]+)\")
match = re.match(f\"^{pattern}$\", uri)
if match:
return match.groupdict()
return None
<|"|>}<tool_call|><|tool_response>
Turn 13at 218 s350 tokens out14,292 prompt tokens
Now let's run the reproduction script again to verify the fix.
TOOL CALL · run_command
{
"command": "python3 - <<'PY'\nimport pytest\nfrom mcp.server.fastmcp.resources.templates import ResourceTemplate\n\ndef test_resource_template_decoding():\n def my_func(product_identifier: str):\n return product_identifier\n\n template = ResourceTemplate.from_function(\n fn=my_func,\n uri_template=\"products://search/{product_identifier}\",\n name=\"products\",\n )\n\n # This is the case reported in the issue\n uri = \"products://search/stick%20correcteur%20teint%C3%A9%20anti-imperfections\"\n params = template.matches(uri)\n print(f\"Extracted params: {params}\")\n \n # We expect the 'product_identifier' to be decoded\n # 'stick correcteur teinté anti-imperfections'\n \n import asyncio\n async def run():\n resource = await template.create_resource(uri, params)\n content = await resource.read()\n print(f\"Resource content: {content}\")\n assert content == \"stick correcteur teinté anti-imperfections\"\n\n try:\n asyncio.run(run())\n except Exception as e:\n print(f\"Caught exception: {e}\")\n raise e\n\nif __name__ == \"__main__\":\n test_resource_template_decoding()\nPY\n"
}Result of run_command 220 characters
{
"status": "ok",
"stdout": "Extracted params: {'product_identifier': 'stick correcteur teinté anti-imperfections'}\nResource content: stick correcteur teinté anti-imperfections\n",
"stderr": "",
"exit_code": 0
}Generated tokens 350 tokens · stopped: STOP
Now let's run the reproduction script again to verify the fix.
<channel|><|tool_call>call:run_command{command:<|"|>python3 - <<'PY'
import pytest
from mcp.server.fastmcp.resources.templates import ResourceTemplate
def test_resource_template_decoding():
def my_func(product_identifier: str):
return product_identifier
template = ResourceTemplate.from_function(
fn=my_func,
uri_template="products://search/{product_identifier}",
name="products",
)
# This is the case reported in the issue
uri = "products://search/stick%20correcteur%20teint%C3%A9%20anti-imperfections"
params = template.matches(uri)
print(f"Extracted params: {params}")
# We expect the 'product_identifier' to be decoded
# 'stick correcteur teinté anti-imperfections'
import asyncio
async def run():
resource = await template.create_resource(uri, params)
content = await resource.read()
print(f"Resource content: {content}")
assert content == "stick correcteur teinté anti-imperfections"
try:
asyncio.run(run())
except Exception as e:
print(f"Caught exception: {e}")
raise e
if __name__ == "__main__":
test_resource_template_decoding()
PY
<|"|>}<tool_call|><|tool_response>
Turn 14at 224 s72 tokens out14,716 prompt tokens
The reproduction now passes. I should also run the existing tests in `tests/server/fastmcp/resources/` to make sure I didn't break anything.
TOOL CALL · run_command
{
"command": "pytest tests/server/fastmcp/resources -q --tb=short --no-header"
}Result of run_command 10,699 characters
{
"status": "error",
"error_type": "CommandError",
"error_message": "bringing up nodes...\n48 workers [55 items]\n\nscheduling tests via LoadScheduling\n\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_text \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_error_handling \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_without_annotations \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_read_binary_file \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_mime_type \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_resource \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_creation \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_custom_type_conversion \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_with_metadata \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_add_resource \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_json_conversion \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_str_path_conversion \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_without_metadata \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_disable_warn_on_duplicate_resources \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_basemodel_conversion \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_from_function \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_list_resources \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_error \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_create_resource \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_read_abstract \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_unknown_resource \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_uri_accepts_any_string \n[gw20]\u001b[36m [ 1%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_with_annotations \n[gw37]\u001b[36m [ 3%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_with_annotations \n[gw10]\u001b[36m [ 5%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_json_conversion \n[gw0]\u001b[36m [ 7%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_creation \ntests/server/fastmcp/resources/test_resources.py::TestResourceAnnotations::test_resource_without_annotations \n[gw0]\u001b[36m [ 9%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resources.py::TestResourceAnnotations::test_resource_without_annotations \n[gw24]\u001b[36m [ 10%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_unknown_resource \n[gw14]\u001b[36m [ 12%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \n[gw30]\u001b[36m [ 14%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \n[gw25]\u001b[36m [ 16%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_list_resources \n[gw27]\u001b[36m [ 18%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \n[gw5]\u001b[36m [ 20%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \ntests/server/fastmcp/resources/test_resources.py::TestResourceMetadata::test_resource_with_metadata \n[gw5]\u001b[36m [ 21%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource",
"details": {
"stdout": "bringing up nodes...\n48 workers [55 items]\n\nscheduling tests via LoadScheduling\n\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_text \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_error_handling \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_without_annotations \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_read_binary_file \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_mime_type \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_resource \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_creation \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_custom_type_conversion \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_with_metadata \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_add_resource \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_json_conversion \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_str_path_conversion \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_without_metadata \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_disable_warn_on_duplicate_resources \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_basemodel_conversion \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_from_function \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_list_resources \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_error \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_create_resource \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_read_abstract \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_unknown_resource \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_uri_accepts_any_string \n[gw20]\u001b[36m [ 1%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_with_annotations \n[gw37]\u001b[36m [ 3%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_with_annotations \n[gw10]\u001b[36m [ 5%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_json_conversion \n[gw0]\u001b[36m [ 7%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_creation \ntests/server/fastmcp/resources/test_resources.py::TestResourceAnnotations::test_resource_without_annotations \n[gw0]\u001b[36m [ 9%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resources.py::TestResourceAnnotations::test_resource_without_annotations \n[gw24]\u001b[36m [ 10%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_unknown_resource \n[gw14]\u001b[36m [ 12%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \n[gw30]\u001b[36m [ 14%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \n[gw25]\u001b[36m [ 16%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_list_resources \n[gw27]\u001b[36m [ 18%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \n[gw5]\u001b[36m [ 20%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \ntests/server/fastmcp/resources/test_resources.py::TestResourceMetadata::test_resource_with_metadata \n[gw5]\u001b[36m [ 21%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource",
"stderr": "",
"exit_code": 1
}
}Generated tokens 72 tokens · stopped: STOP
The reproduction now passes.
I should also run the existing tests in `tests/server/fastmcp/resources/` to make sure I didn't break anything.
<channel|><|tool_call>call:run_command{command:<|"|>pytest tests/server/fastmcp/resources -q --tb=short --no-header<|"|>}<tool_call|><|tool_response>
Turn 15at 331 s142 tokens out7,129 prompt tokens
The output was truncated. I should run pytest with fewer workers to get a clearer output, or just check if it actually failed. Wait, `exit_code: 1` means it failed. But the output showed nothing but PASSED. The output was truncated. Let me run it without `pytest-xdist` (or just normally) and redirect to a file.
TOOL CALL · run_command
{
"command": "pytest tests/server/fastmcp/resources -q --tb=short --no-header > /tmp/pytest_resources.log 2>&1\ntail -n 100 /tmp/pytest_resources.log"
}Result of run_command 5,477 characters
{
"status": "ok",
"stdout": "tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_without_metadata \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_relative_path_error \n[gw4]\u001b[36m [ 14%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_relative_path_error \ntests/server/fastmcp/resources/test_resources.py::TestAnnotationsValidation::test_audience_validation \n[gw4]\u001b[36m [ 16%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resources.py::TestAnnotationsValidation::test_audience_validation \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateMetadata::test_template_created_resources_inherit_metadata \n[gw41]\u001b[36m [ 18%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateMetadata::test_template_created_resources_inherit_metadata \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \n[gw19]\u001b[36m [ 20%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_custom_type_conversion \n[gw10]\u001b[36m [ 21%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_custom_type_conversion \n[gw13]\u001b[36m [ 23%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_basemodel_conversion \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_created_resources_inherit_annotations \n[gw40]\u001b[36m [ 25%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_created_resources_inherit_annotations \ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_function_resource_creation \n[gw7]\u001b[36m [ 27%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_function_resource_creation \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_mime_type \n[gw46]\u001b[36m [ 29%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_mime_type \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_create_resource \n[gw24]\u001b[36m [ 30%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \n[gw5]\u001b[36m [ 32%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \ntests/server/fastmcp/resources/test_resources.py::TestResourceMetadata::test_resource_with_metadata \n[gw9]\u001b[36m [ 34%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_binary \ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_str_path_conversion \n[gw1]\u001b[36m [ 36%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_str_path_conversion \ntests/server/fastmcp/resources/test_resources.py::TestResourceAnnotations::test_resource_annotations_in_fastmcp \n[gw25]\u001b[36m [ 38%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \n[gw29]\u001b[36m [ 40%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_creation \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_with_annotations \ntests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_uri_accepts_any_string \n[gw42]\u001b[36m [ 41%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resources.py::TestResourceValidation::test_resource_uri_accepts_any_string \n[gw16]\u001b[36m [ 43%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_without_annotations \n[gw37]\u001b[36m [ 45%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_without_annotations \ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplateAnnotations::test_template_annotations_in_fastmcp \n[gw12]\u001b[36m [ 47%] \u001b[0m\u001b[32mPASSED\u001b[0m tests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_error_handling \ntests/server/fastmcp/resources/test_resource_templat",
"stderr": "",
"exit_code": 0
}Generated tokens 142 tokens · stopped: STOP
The output was truncated. I should run pytest with fewer workers to get a clearer output, or just check if it actually failed.
Wait, `exit_code: 1` means it failed. But the output showed nothing but PASSED.
The output was truncated. Let me run it without `pytest-xdist` (or just normally) and redirect to a file.<channel|><|tool_call>call:run_command{command:<|"|>pytest tests/server/fastmcp/resources -q --tb=short --no-header > /tmp/pytest_resources.log 2>&1
tail -n 100 /tmp/pytest_resources.log<|"|>}<tool_call|><|tool_response>
Turn 16at 378 s243 tokens out9,429 prompt tokens
The previous `pytest` run succeeded (exit code 0). The earlier `exit_code: 1` might have been due to the `CommandError` being raised by the wrapper if the stdout was too large or something, but `tail` shows PASSED. Wait, the `run_command` return value for the FIRST pytest was `{"status": "error", "error_type": "CommandError"}`. This is strange.
Let's look closer at the first pytest run:
`"status": "error", "error_type": "CommandError", "error_message": "bringing up nodes...\n..."`
It seems `run_command` might be interpreting some output as an error? No, `CommandError` usually means the process failed.
Wait, if I look at the stdout of the first run, it's huge.
Let's try running it without `pytest-xdist` to avoid the noise and verify.
TOOL CALL · run_command
{
"command": "pytest tests/server/fastmcp/resources -n 0 -q --tb=short --no-header"
}Result of run_command 11,565 characters
{
"status": "error",
"error_type": "CommandError",
"error_message": "\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_creation \u001b[32mPASSED\u001b[0m\u001b[32m [ 1%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_str_path_conversion \u001b[32mPASSED\u001b[0m\u001b[32m [ 3%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_read_text_file \u001b[32mPASSED\u001b[0m\u001b[32m [ 5%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_read_binary_file \u001b[32mPASSED\u001b[0m\u001b[32m [ 7%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_relative_path_error \u001b[32mPASSED\u001b[0m\u001b[32m [ 9%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \u001b[32mPASSED\u001b[0m\u001b[32m [ 10%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_permission_error \u001b[31mFAILED\u001b[0m\u001b[31m [ 12%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_function_resource_creation \u001b[32mPASSED\u001b[0m\u001b[31m [ 14%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_text \u001b[32mPASSED\u001b[0m\u001b[31m [ 16%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_binary \u001b[32mPASSED\u001b[0m\u001b[31m [ 18%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_json_conversion \u001b[32mPASSED\u001b[0m\u001b[31m [ 20%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_error_handling \u001b[32mPASSED\u001b[0m\u001b[31m [ 21%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_basemodel_conversion \u001b[32mPASSED\u001b[0m\u001b[31m [ 23%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_custom_type_conversion \u001b[32mPASSED\u001b[0m\u001b[31m [ 25%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \u001b[32mPASSED\u001b[0m\u001b[31m [ 27%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_from_function \u001b[32mPASSED\u001b[0m\u001b[31m [ 29%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_with_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 30%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 32%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_add_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 34%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_add_duplicate_resource \n\u001b[1m-------------------------------- live log call ---------------------------------\u001b[0m\n\u001b[33mWARNING \u001b[0m mcp.server.fastmcp.resources.resource_manager:resource_manager.py:52 Resource already exists: file:///tmp/tmpf5emyl7r\n\u001b[32mPASSED\u001b[0m\u001b[31m [ 36%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_warn_on_duplicate_resources \n\u001b[1m-------------------------------- live log call ---------------------------------\u001b[0m\n\u001b[33mWARNING \u001b[0m mcp.server.fastmcp.resources.resource_manager:resource_manager.py:52 Resource already exists: file:///tmp/tmpge8av5hh\n\u001b[32mPASSED\u001b[0m\u001b[31m [ 38%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_disable_warn_on_duplicate_resources \u001b[32mPASSED\u001b[0m\u001b[31m [ 40%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 41%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_resource_from_template \u001b[32mPASSED\u001b[0m\u001b[31m [ 43%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_unknown_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 45%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_list_resources \u001b[32mPASSED\u001b[0m\u001b[31m [ 47%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 49%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_without_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 50%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_creation \u001b[32mPASSED\u001b[0m\u001b[31m [ 52%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \u001b[32mPASSED\u001b[0m\u001b[31m [ 54%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_create_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 56%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_error \u001b[32mPASSED\u001b[0m\u001b[31m [ 58%]\u001b[0m\ntests/server/fastmcp/resources/test_reso",
"details": {
"stdout": "\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_creation \u001b[32mPASSED\u001b[0m\u001b[32m [ 1%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_file_resource_str_path_conversion \u001b[32mPASSED\u001b[0m\u001b[32m [ 3%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_read_text_file \u001b[32mPASSED\u001b[0m\u001b[32m [ 5%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_read_binary_file \u001b[32mPASSED\u001b[0m\u001b[32m [ 7%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_relative_path_error \u001b[32mPASSED\u001b[0m\u001b[32m [ 9%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_missing_file_error \u001b[32mPASSED\u001b[0m\u001b[32m [ 10%]\u001b[0m\ntests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_permission_error \u001b[31mFAILED\u001b[0m\u001b[31m [ 12%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_function_resource_creation \u001b[32mPASSED\u001b[0m\u001b[31m [ 14%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_text \u001b[32mPASSED\u001b[0m\u001b[31m [ 16%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_read_binary \u001b[32mPASSED\u001b[0m\u001b[31m [ 18%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_json_conversion \u001b[32mPASSED\u001b[0m\u001b[31m [ 20%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_error_handling \u001b[32mPASSED\u001b[0m\u001b[31m [ 21%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_basemodel_conversion \u001b[32mPASSED\u001b[0m\u001b[31m [ 23%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_custom_type_conversion \u001b[32mPASSED\u001b[0m\u001b[31m [ 25%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_async_read_text \u001b[32mPASSED\u001b[0m\u001b[31m [ 27%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResource::test_from_function \u001b[32mPASSED\u001b[0m\u001b[31m [ 29%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_with_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 30%]\u001b[0m\ntests/server/fastmcp/resources/test_function_resources.py::TestFunctionResourceMetadata::test_from_function_without_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 32%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_add_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 34%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_add_duplicate_resource \n\u001b[1m-------------------------------- live log call ---------------------------------\u001b[0m\n\u001b[33mWARNING \u001b[0m mcp.server.fastmcp.resources.resource_manager:resource_manager.py:52 Resource already exists: file:///tmp/tmpf5emyl7r\n\u001b[32mPASSED\u001b[0m\u001b[31m [ 36%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_warn_on_duplicate_resources \n\u001b[1m-------------------------------- live log call ---------------------------------\u001b[0m\n\u001b[33mWARNING \u001b[0m mcp.server.fastmcp.resources.resource_manager:resource_manager.py:52 Resource already exists: file:///tmp/tmpge8av5hh\n\u001b[32mPASSED\u001b[0m\u001b[31m [ 38%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_disable_warn_on_duplicate_resources \u001b[32mPASSED\u001b[0m\u001b[31m [ 40%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 41%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_resource_from_template \u001b[32mPASSED\u001b[0m\u001b[31m [ 43%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_get_unknown_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 45%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManager::test_list_resources \u001b[32mPASSED\u001b[0m\u001b[31m [ 47%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_with_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 49%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_without_metadata \u001b[32mPASSED\u001b[0m\u001b[31m [ 50%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_creation \u001b[32mPASSED\u001b[0m\u001b[31m [ 52%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_matches \u001b[32mPASSED\u001b[0m\u001b[31m [ 54%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_create_resource \u001b[32mPASSED\u001b[0m\u001b[31m [ 56%]\u001b[0m\ntests/server/fastmcp/resources/test_resource_template.py::TestResourceTemplate::test_template_error \u001b[32mPASSED\u001b[0m\u001b[31m [ 58%]\u001b[0m\ntests/server/fastmcp/resources/test_reso",
"stderr": "",
"exit_code": 1
}
}Generated tokens 243 tokens · stopped: STOP
The previous `pytest` run succeeded (exit code 0). The earlier `exit_code: 1` might have been due to the `CommandError` being raised by the wrapper if the stdout was too large or something, but `tail` shows PASSED. Wait, the `run_command` return value for the FIRST pytest was `{"status": "error", "error_type": "CommandError"}`. This is strange.
Let's look closer at the first pytest run:
`"status": "error", "error_type": "CommandError", "error_message": "bringing up nodes...\n..."`
It seems `run_command` might be interpreting some output as an error? No, `CommandError` usually means the process failed.
Wait, if I look at the stdout of the first run, it's huge.
Let's try running it without `pytest-xdist` to avoid the noise and verify.
<channel|><|tool_call>call:run_command{command:<|"|>pytest tests/server/fastmcp/resources -n 0 -q --tb=short --no-header<|"|>}<tool_call|><|tool_response>
Turn 17at 394 s176 tokens out14,955 prompt tokens
It seems `tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_permission_error` is failing. This is unrelated to the change I made (which only affected `ResourceTemplate.matches`). Let's verify this failure existed before my change. I will revert my change and run that test. No, wait, I should just verify that the failure is not caused by my change. My change only affected `ResourceTemplate.matches`. `TestFileResource` probably doesn't use `ResourceTemplate.matches`. Let's check `tests/server/fastmcp/resources/test_file_resources.py`.
TOOL CALL · read_file
{
"filepath": "tests/server/fastmcp/resources/test_file_resources.py"
}Result of read_file 4,268 characters
{
"status": "ok",
"filepath": "tests/server/fastmcp/resources/test_file_resources.py",
"content": "import os\nfrom pathlib import Path\nfrom tempfile import NamedTemporaryFile\n\nimport pytest\n\nfrom mcp.server.fastmcp.resources import FileResource\n\n\n@pytest.fixture\ndef temp_file():\n \"\"\"Create a temporary file for testing.\n\n File is automatically cleaned up after the test if it still exists.\n \"\"\"\n content = \"test content\"\n with NamedTemporaryFile(mode=\"w\", delete=False) as f:\n f.write(content)\n path = Path(f.name).resolve()\n yield path\n try: # pragma: no cover\n path.unlink()\n except FileNotFoundError: # pragma: no cover\n pass # File was already deleted by the test\n\n\nclass TestFileResource:\n \"\"\"Test FileResource functionality.\"\"\"\n\n def test_file_resource_creation(self, temp_file: Path):\n \"\"\"Test creating a FileResource.\"\"\"\n resource = FileResource(\n uri=temp_file.as_uri(),\n name=\"test\",\n description=\"test file\",\n path=temp_file,\n )\n assert str(resource.uri) == temp_file.as_uri()\n assert resource.name == \"test\"\n assert resource.description == \"test file\"\n assert resource.mime_type == \"text/plain\" # default\n assert resource.path == temp_file\n assert resource.is_binary is False # default\n\n def test_file_resource_str_path_conversion(self, temp_file: Path):\n \"\"\"Test FileResource handles string paths.\"\"\"\n resource = FileResource(\n uri=f\"file://{temp_file}\",\n name=\"test\",\n path=Path(str(temp_file)),\n )\n assert isinstance(resource.path, Path)\n assert resource.path.is_absolute()\n\n @pytest.mark.anyio\n async def test_read_text_file(self, temp_file: Path):\n \"\"\"Test reading a text file.\"\"\"\n resource = FileResource(\n uri=f\"file://{temp_file}\",\n name=\"test\",\n path=temp_file,\n )\n content = await resource.read()\n assert content == \"test content\"\n assert resource.mime_type == \"text/plain\"\n\n @pytest.mark.anyio\n async def test_read_binary_file(self, temp_file: Path):\n \"\"\"Test reading a file as binary.\"\"\"\n resource = FileResource(\n uri=f\"file://{temp_file}\",\n name=\"test\",\n path=temp_file,\n is_binary=True,\n )\n content = await resource.read()\n assert isinstance(content, bytes)\n assert content == b\"test content\"\n\n def test_relative_path_error(self):\n \"\"\"Test error on relative path.\"\"\"\n with pytest.raises(ValueError, match=\"Path must be absolute\"):\n FileResource(\n uri=\"file:///test.txt\",\n name=\"test\",\n path=Path(\"test.txt\"),\n )\n\n @pytest.mark.anyio\n async def test_missing_file_error(self, temp_file: Path):\n \"\"\"Test error when file doesn't exist.\"\"\"\n # Create path to non-existent file\n missing = temp_file.parent / \"missing.txt\"\n resource = FileResource(\n uri=\"file:///missing.txt\",\n name=\"test\",\n path=missing,\n )\n with pytest.raises(ValueError, match=\"Error reading file\"):\n await resource.read()\n\n @pytest.mark.skipif(os.name == \"nt\", reason=\"File permissions behave differently on Windows\")\n @pytest.mark.anyio\n async def test_permission_error(self, temp_file: Path): # pragma: no cover\n \"\"\"Test reading a file without permissions.\"\"\"\n temp_file.chmod(0o000) # Remove all permissions\n try:\n resource = FileResource(\n uri=temp_file.as_uri(),\n name=\"test\",\n path=temp_file,\n )\n with pytest.raises(ValueError, match=\"Error reading file\"):\n await resource.read()\n finally:\n temp_file.chmod(0o644) # Restore permissions",
"start_line": 1,
"end_line": 116,
"total_lines": 116,
"is_truncated": false
}Generated tokens 176 tokens · stopped: STOP
It seems `tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_permission_error` is failing. This is unrelated to the change I made (which only affected `ResourceTemplate.matches`).
Let's verify this failure existed before my change. I will revert my change and run that test.
No, wait, I should just verify that the failure is not caused by my change. My change only affected `ResourceTemplate.matches`. `TestFileResource` probably doesn't use `ResourceTemplate.matches`.
Let's check `tests/server/fastmcp/resources/test_file_resources.py`.
<channel|><|tool_call>call:read_file{filepath:<|"|>tests/server/fastmcp/resources/test_file_resources.py<|"|>}<tool_call|><|tool_response>
Patch, tests and logs
Final code change Included
diff --git a/src/mcp/server/fastmcp/resources/templates.py b/src/mcp/server/fastmcp/resources/templates.py
index 89a8ceb..e993cba 100644
--- a/src/mcp/server/fastmcp/resources/templates.py
+++ b/src/mcp/server/fastmcp/resources/templates.py
@@ -4,6 +4,7 @@ from __future__ import annotations
import inspect
import re
+from urllib.parse import unquote
from collections.abc import Callable
from typing import TYPE_CHECKING, Any
@@ -88,7 +89,7 @@ class ResourceTemplate(BaseModel):
pattern = self.uri_template.replace("{", "(?P<").replace("}", ">[^/]+)")
match = re.match(f"^{pattern}$", uri)
if match:
- return match.groupdict()
+ return {k: unquote(v) for k, v in match.groupdict().items()}
return None
async def create_resource(
Test output Included
============================= test session starts ============================== created: 48/48 workers 48 workers [12 items] scheduling tests via LoadScheduling tests/issues/test_973_url_decoding.py::test_template_matches_decodes_accented_characters tests/issues/test_973_url_decoding.py::test_template_matches_decodes_complex_phrase tests/server/test_stateless_mode.py::test_elicit_url_fails_in_stateless_mode tests/server/test_stateless_mode.py::test_create_message_fails_in_stateless_mode tests/issues/test_973_url_decoding.py::test_template_matches_decodes_space tests/server/test_stateless_mode.py::test_stateless_error_message_is_actionable tests/server/test_stateless_mode.py::test_exception_has_method_attribute tests/server/test_stateless_mode.py::test_stateful_mode_does_not_raise_stateless_error [gw7] [ 8%] PASSED tests/server/test_stateless_mode.py::test_elicit_url_fails_in_stateless_mode [gw10] [ 16%] PASSED tests/server/test_stateless_mode.py::test_exception_has_method_attribute tests/server/test_stateless_mode.py::test_elicit_form_fails_in_stateless_mode [gw6] [ 25%] PASSED tests/server/test_stateless_mode.py::test_elicit_form_fails_in_stateless_mode [gw9] [ 33%] PASSED tests/server/test_stateless_mode.py::test_stateless_error_message_is_actionable [gw5] [ 41%] PASSED tests/server/test_stateless_mode.py::test_create_message_fails_in_stateless_mode [gw0] [ 50%] PASSED tests/issues/test_973_url_decoding.py::test_template_matches_decodes_space tests/server/test_stateless_mode.py::test_list_roots_fails_in_stateless_mode [gw4] [ 58%] PASSED tests/server/test_stateless_mode.py::test_list_roots_fails_in_stateless_mode [gw11] [ 66%] PASSED tests/server/test_stateless_mode.py::test_stateful_mode_does_not_raise_stateless_error [gw2] [ 75%] PASSED tests/issues/test_973_url_decoding.py::test_template_matches_decodes_complex_phrase tests/server/test_stateless_mode.py::test_elicit_deprecated_fails_in_stateless_mode [gw8] [ 83%] PASSED tests/server/test_stateless_mode.py::test_elicit_deprecated_fails_in_stateless_mode tests/issues/test_973_url_decoding.py::test_template_matches_preserves_plus_sign [gw3] [ 91%] PASSED tests/issues/test_973_url_decoding.py::test_template_matches_preserves_plus_sign [gw1] [100%] PASSED tests/issues/test_973_url_decoding.py::test_template_matches_decodes_accented_characters ═══════════════════════════════ inline-snapshot ════════════════════════════════ INFO: inline-snapshot was disabled because you used xdist. This means that tests with snapshots will continue to run, but snapshot(x) will only return x and inline-snapshot will not be able to fix snapshots or generate reports. ==================================== PASSES ==================================== - generated xml file: /tmp/rebench-grade-7e3861b7f4e346eeaf5a9a4fe3ca06a4.xml -- =========================== short test summary info ============================ PASSED tests/server/test_stateless_mode.py::test_elicit_url_fails_in_stateless_mode PASSED tests/server/test_stateless_mode.py::test_exception_has_method_attribute PASSED tests/server/test_stateless_mode.py::test_elicit_form_fails_in_stateless_mode PASSED tests/server/test_stateless_mode.py::test_stateless_error_message_is_actionable PASSED tests/server/test_stateless_mode.py::test_create_message_fails_in_stateless_mode PASSED tests/issues/test_973_url_decoding.py::test_template_matches_decodes_space PASSED tests/server/test_stateless_mode.py::test_list_roots_fails_in_stateless_mode PASSED tests/server/test_stateless_mode.py::test_stateful_mode_does_not_raise_stateless_error PASSED tests/issues/test_973_url_decoding.py::test_template_matches_decodes_complex_phrase PASSED tests/server/test_stateless_mode.py::test_elicit_deprecated_fails_in_stateless_mode PASSED tests/issues/test_973_url_decoding.py::test_template_matches_preserves_plus_sign PASSED tests/issues/test_973_url_decoding.py::test_template_matches_decodes_accented_characters ============================= 12 passed in 24.52s ==============================
Test errors Included
Test report (JUnit) Included
<?xml version="1.0" encoding="utf-8"?><testsuites name="pytest tests"><testsuite name="pytest" errors="0" failures="0" skipped="0" tests="12" time="24.518" timestamp="2026-11-14T03:41:54.853979+00:00" hostname="7f825bff0f6b"><testcase classname="tests.issues.test_973_url_decoding" name="test_template_matches_decodes_space" time="0.003" /><testcase classname="tests.issues.test_973_url_decoding" name="test_template_matches_decodes_complex_phrase" time="0.003" /><testcase classname="tests.server.test_stateless_mode" name="test_create_message_fails_in_stateless_mode" time="0.003" /><testcase classname="tests.server.test_stateless_mode" name="test_elicit_url_fails_in_stateless_mode" time="0.002" /><testcase classname="tests.server.test_stateless_mode" name="test_exception_has_method_attribute" time="0.002" /><testcase classname="tests.server.test_stateless_mode" name="test_stateless_error_message_is_actionable" time="0.002" /><testcase classname="tests.server.test_stateless_mode" name="test_elicit_form_fails_in_stateless_mode" time="0.002" /><testcase classname="tests.server.test_stateless_mode" name="test_list_roots_fails_in_stateless_mode" time="0.002" /><testcase classname="tests.server.test_stateless_mode" name="test_stateful_mode_does_not_raise_stateless_error" time="0.002" /><testcase classname="tests.server.test_stateless_mode" name="test_elicit_deprecated_fails_in_stateless_mode" time="0.002" /><testcase classname="tests.issues.test_973_url_decoding" name="test_template_matches_preserves_plus_sign" time="0.003" /><testcase classname="tests.issues.test_973_url_decoding" name="test_template_matches_decodes_accented_characters" time="0.004" /></testsuite></testsuites>
Agent log Included
[ 0.0s] 📋 System Prompt: You are a principal Python software engineer resolving a repository issue in `/workspace`.
[ 0.0s] 🎯 Task Prompt: You are evaluating a software engineering task for repository
modelcontextprotocol/python-sdk.
[ 16.9s] 💭 (763 chars) "The user is reporting that dynamic resource parameters in the MCP Python SDK are not being
URL-decoded before being pass..."
[ 16.9s] 🔧 run_command grep -rn --include="*.py" "resource" src/mcp/server | head -n 20
[ 16.9s] → src/mcp/server/fastmcp/resources/templates.py:12:from mcp.server.fastmcp.resources.types import
FunctionResource, Resour
[ 29.4s] 💭 (374 chars) "The file `src/mcp/server/fastmcp/resources/templates.py` seems very relevant, especially
`create_resource`.
Also, the ex..."
[ 29.4s] 🔧 run_command grep -rn "def resource" src/mcp/server
[ 29.4s] → src/mcp/server/fastmcp/server.py:519: def resource(
[ 38.4s] 💭 (279 chars) "Okay, `@mcp.resource` is defined in `src/mcp/server/fastmcp/server.py`.
Let's examine `src/mcp/server/fastmcp/server.py..."
[ 38.4s] 📖 read_file (src/mcp/server/fastmcp/server.py)
[ 38.5s] ✓ {'status': 'ok', 'filepath': 'src/mcp/server/fastmcp/server.py', 'content': ' def resource(\n
self,\n u…
[ 47.2s] 💭 (294 chars) "The `resource` decorator calls `self._resource_manager.add_template`.
I need to see how `self._resource_manager` is impl..."
[ 47.2s] 🔧 run_command find src/mcp/server/fastmcp/resources -name "*.py"
[ 47.2s] → src/mcp/server/fastmcp/resources/templates.py
[ 51.1s] 💭 (75 chars) "It's `src/mcp/server/fastmcp/resources/resource_manager.py`. Let's read it."
[ 51.1s] 📖 read_file (src/mcp/server/fastmcp/resources/resource_manager.py)
[ 51.1s] ✓ {'status': 'ok', 'filepath': 'src/mcp/server/fastmcp/resources/resource_manager.py', 'content':
'"""Resource manager fun…
[ 60.9s] 💭 (460 chars) "In `ResourceManager.get_resource`:
```python
# Then check templates
for template in self._templates.val..."
[ 60.9s] 📖 read_file (src/mcp/server/fastmcp/resources/templates.py)
[ 60.9s] ✓ {'status': 'ok', 'filepath': 'src/mcp/server/fastmcp/resources/templates.py', 'content': '"""Resource
template functiona…
[ 84.9s] 💭 (1659 chars) "The `matches` method extracts parameters using regex:
```python
def matches(self, uri: str) -> dict[str, Any] | Non..."
[ 84.9s] 🔧 run_command find tests -name "*resource*"
[ 84.9s] → tests/server/fastmcp/resources
[ 92.0s] 💭 (139 chars) "`tests/server/fastmcp/resources/test_resource_template.py` seems like the best place.
Let's read it to see if I can add..."
[ 92.0s] 📖 read_file (tests/server/fastmcp/resources/test_resource_template.py)
[ 92.1s] ✓ {'status': 'ok', 'filepath': 'tests/server/fastmcp/resources/test_resource_template.py', 'content':
'import json\nfrom t…
[ 119.9s] 💭 (236 chars) "I'll create a reproduction script using `pytest` to demonstrate the failure.
Specifically, I want to see that `template..."
[ 119.9s] 🔧 run_command (38 lines) python3 - <<'PY'
[ 121.1s] → error (exit 0):
[ 161.1s] 💭 (2406 chars) "The reproduction confirms the bug.
`Extracted params: {'product_identifier': 'stick%20correcteur%20teint%C3%A9%20anti-im..."
[ 161.1s] 📖 read_file (src/mcp/server/fastmcp/resources/templates.py)
[ 161.2s] ✓ {'status': 'ok', 'filepath': 'src/mcp/server/fastmcp/resources/templates.py', 'content': '"""Resource
template functiona…
[ 182.9s] 💭 (1342 chars) "I will add `from urllib.parse import unquote` and update `matches`.
Wait, I should also verify if this affects anything..."
[ 182.9s] ✏️ edit_file (src/mcp/server/fastmcp/resources/templates.py)
[ 183.1s] ✓ {'status': 'ok', 'filepath': 'src/mcp/server/fastmcp/resources/templates.py', 'occurrences': 1,
'strategy': 'exact', 'di…
[ 196.6s] 💭 (21 chars) "Now update `matches`."
[ 196.6s] ✏️ edit_file (src/mcp/server/fastmcp/resources/templates.py)
[ 196.8s] ✓ {'status': 'ok', 'filepath': 'src/mcp/server/fastmcp/resources/templates.py', 'occurrences': 1,
'strategy': 'unescaped',…
[ 210.9s] 💭 (62 chars) "Now let's run the reproduction script again to verify the fix."
[ 210.9s] 🔧 run_command (38 lines) python3 - <<'PY'
[ 211.3s] → Extracted params: {'product_identifier': 'stick correcteur teinté anti-imperfections'}
[ 216.8s] 💭 (141 chars) "The reproduction now passes.
I should also run the existing tests in `tests/server/fastmcp/resources/` to make sure I d..."
[ 216.8s] 🔧 run_command pytest tests/server/fastmcp/resources -q --tb=short --no-header
[ 242.1s] → error (exit 0):
[ 323.8s] 💭 (312 chars) "The output was truncated. I should run pytest with fewer workers to get a clearer output, or
just check if it actually f..."
[ 323.8s] 🔧 run_command (2 lines) pytest tests/server/fastmcp/resources -q --tb=short --no-header > /tmp/pytest_re
[ 349.3s] →
tests/server/fastmcp/resources/test_resource_manager.py::TestResourceManagerMetadata::test_add_template_without_metadata
[ 371.4s] 💭 (746 chars) "The previous `pytest` run succeeded (exit code 0). The earlier `exit_code: 1` might have
been due to the `CommandError` ..."
[ 371.4s] 🔧 run_command pytest tests/server/fastmcp/resources -n 0 -q --tb=short --no-header
[ 372.1s] → error (exit 0):
[ 387.3s] 💭 (568 chars) "It seems
`tests/server/fastmcp/resources/test_file_resources.py::TestFileResource::test_permission_error` is failing. Th..."
[ 387.3s] 📖 read_file (tests/server/fastmcp/resources/test_file_resources.py)
[ 387.4s] ✓ {'status': 'ok', 'filepath': 'tests/server/fastmcp/resources/test_file_resources.py', 'content': 'import
os\nfrom pathli…
Native result row
{
"agent_error": "Agent exceeded session timeout (7.5 min)",
"duration_seconds": 486.07,
"error": "Agent exceeded session timeout (7.5 min)",
"grade": {
"collected_tests": 12,
"competition_junit_ok": true,
"error": null,
"required_issues_count": 0,
"resolved": true,
"status_counts": {
"PASSED": 12
},
"strict_clean_patch": true,
"test_exit_code": 0
},
"instance_id": "modelcontextprotocol__python-sdk-1864",
"pass_idx": 0,
"patch_chars": 802,
"phase1_seconds": 459.75,
"repo": "modelcontextprotocol/python-sdk",
"request_log_path": "/kaggle-root/working/r31/rollouts_X/requests/modelcontextprotocol__python-sdk-1864__p0__r3.jsonl",
"resolved": true,
"rollout_idx": 3,
"run_key": "modelcontextprotocol__python-sdk-1864__p0__r3",
"strict_clean_patch": true,
"tool_calls": 17,
"total_llm_calls": 17,
"trace_path": "/kaggle-root/working/r31/rollouts_X/traces/trace_modelcontextprotocol__python-sdk-1864__p0__r3.json"
}