Refactor provider execution: components own their execution#2663
Conversation
…nents - Remove execution methods (call_tool, read_resource, etc.) from Provider base - Add FastMCPProvider* wrapper classes that delegate to child server middleware - Move task routing to Tool._run() using contextvars (_task_metadata, _tool_call_key) - Add convert_to_tool_result(result, output_schema) utility for Docket results - Add convert_to_prompt_result() utility for prompt task results - Pass namespaced key via add_to_docket(name=) for mounted tool lookup
All components now use explicit fn_key (function lookup) and task_key (result storage) parameters instead of relying on implicit key handling. This fixes mounted component task execution where the MCP-visible key differs from the Docket-registered function name.
Tests verify middleware runs at parent, child, and grandchild levels for tools, resources, prompts, and resource templates.
…n progress Work in progress on refactoring execution to use component _read()/_run()/_render() methods. Template background tasks not yet working - needs fix for Docket key lookup.
Pass Tool/Prompt/Resource/Template to conversion functions instead of individual attributes, ensuring access to serializer, output_schema, mime_type, etc. Also fixes mixed-content output schema validation.
…helper - Add convert_result() instance methods to all component types (Tool, Prompt, Resource, ResourceTemplate) - Extract duplicated task routing logic into check_background_task() helper - Fix type annotations on FastMCPProviderResource.read() and FastMCPProviderPrompt.render() - Update protocol.py to use component.convert_result() uniformly
marvin-context-protocol
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added
enhancement
WalkthroughThis PR implements the SEP-1686 background task protocol across the FastMCP codebase. Changes introduce a unified task submission and routing system by adding Possibly related PRs
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🧹 Nitpick comments (2)
src/fastmcp/resources/template.py (1)
306-329: Unuseduriparameter flagged by static analysis.The
uriparameter is declared but never used in this method. The method usesparamsdirectly for theread()call. Ifuriis intentionally unused (e.g., for API consistency withResourceTemplate._read), consider prefixing with underscore to suppress the warning.🔎 Proposed fix
async def _read( - self, uri: str, params: dict[str, Any] + self, _uri: str, params: dict[str, Any] ) -> ResourceContent | mcp.types.CreateTaskResult:src/fastmcp/server/providers/fastmcp_provider.py (1)
326-375: Unuseduriparameter in_readmethod.Similar to
FunctionResourceTemplate._read, theuriparameter is unused. The method constructsoriginal_urifrom_original_uri_templateandparamsinstead.🔎 Proposed fix
async def _read( - self, uri: str, params: dict[str, Any] + self, _uri: str, params: dict[str, Any] ) -> ResourceContent | mcp.types.CreateTaskResult:
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⛔ Files ignored due to path filters (4)
tests/server/providers/test_fastmcp_provider.pyis excluded by none and included by nonetests/server/tasks/test_custom_subclass_tasks.pyis excluded by none and included by nonetests/server/tasks/test_task_mount.pyis excluded by none and included by nonetests/server/test_providers.pyis excluded by none and included by none
📒 Files selected for processing (15)
examples/providers/sqlite/server.py(2 hunks)src/fastmcp/prompts/prompt.py(4 hunks)src/fastmcp/prompts/prompt_manager.py(2 hunks)src/fastmcp/resources/resource.py(3 hunks)src/fastmcp/resources/resource_manager.py(2 hunks)src/fastmcp/resources/template.py(5 hunks)src/fastmcp/server/dependencies.py(3 hunks)src/fastmcp/server/providers/base.py(3 hunks)src/fastmcp/server/providers/fastmcp_provider.py(4 hunks)src/fastmcp/server/proxy.py(2 hunks)src/fastmcp/server/server.py(11 hunks)src/fastmcp/server/tasks/handlers.py(4 hunks)src/fastmcp/server/tasks/protocol.py(2 hunks)src/fastmcp/server/tasks/routing.py(1 hunks)src/fastmcp/tools/tool.py(3 hunks)
🧰 Additional context used
📓 Path-based instructions (1)
src/fastmcp/**/*.py
📄 CodeRabbit inference engine (AGENTS.md)
src/fastmcp/**/*.py: Write Python code with ≥3.10 type annotations required throughout
Never use bare except - be specific with exception types
Files:
src/fastmcp/prompts/prompt_manager.pysrc/fastmcp/server/tasks/protocol.pysrc/fastmcp/server/tasks/handlers.pysrc/fastmcp/server/tasks/routing.pysrc/fastmcp/prompts/prompt.pysrc/fastmcp/server/providers/base.pysrc/fastmcp/server/server.pysrc/fastmcp/server/proxy.pysrc/fastmcp/tools/tool.pysrc/fastmcp/resources/resource_manager.pysrc/fastmcp/server/dependencies.pysrc/fastmcp/server/providers/fastmcp_provider.pysrc/fastmcp/resources/resource.pysrc/fastmcp/resources/template.py
🧠 Learnings (4)
📚 Learning: 2025-11-26T21:51:44.174Z
Learnt from: CR
Repo: jlowin/fastmcp PR: 0
File: .cursor/rules/core-mcp-objects.mdc:0-0
Timestamp: 2025-11-26T21:51:44.174Z
Learning: Review and update related Manager classes (ToolManager, ResourceManager, PromptManager) when modifying MCP object definitions
Applied to files:
src/fastmcp/prompts/prompt_manager.pysrc/fastmcp/server/providers/base.pysrc/fastmcp/server/server.pysrc/fastmcp/server/proxy.pysrc/fastmcp/server/providers/fastmcp_provider.py
📚 Learning: 2025-12-17T03:06:14.522Z
Learnt from: CR
Repo: jlowin/fastmcp PR: 0
File: AGENTS.md:0-0
Timestamp: 2025-12-17T03:06:14.522Z
Learning: Applies to src/fastmcp/**/*.py : Write Python code with ≥3.10 type annotations required throughout
Applied to files:
src/fastmcp/prompts/prompt_manager.pysrc/fastmcp/server/tasks/routing.pysrc/fastmcp/resources/resource_manager.pysrc/fastmcp/resources/template.py
📚 Learning: 2025-12-17T03:06:14.522Z
Learnt from: CR
Repo: jlowin/fastmcp PR: 0
File: AGENTS.md:0-0
Timestamp: 2025-12-17T03:06:14.522Z
Learning: Applies to src/fastmcp/**/__init__.py : Be intentional about re-exports; core types that define a module's purpose should be exported; specialized features can live in submodules; only re-export to fastmcp.* for fundamental types
Applied to files:
src/fastmcp/server/tasks/routing.py
📚 Learning: 2025-11-26T21:51:44.174Z
Learnt from: CR
Repo: jlowin/fastmcp PR: 0
File: .cursor/rules/core-mcp-objects.mdc:0-0
Timestamp: 2025-11-26T21:51:44.174Z
Learning: Note that Resources and Resource Templates are distinct objects but both handled by ResourceManager, requiring coordinated updates when changes affect either object type
Applied to files:
src/fastmcp/resources/template.py
🧬 Code graph analysis (10)
src/fastmcp/prompts/prompt_manager.py (1)
src/fastmcp/prompts/prompt.py (1)
PromptResult(73-115)
examples/providers/sqlite/server.py (4)
src/fastmcp/server/proxy.py (1)
list_tools(103-106)src/fastmcp/server/providers/base.py (2)
list_tools(151-156)get_tool(158-168)src/fastmcp/server/server.py (2)
get_tool(698-715)name(355-356)src/fastmcp/tools/tool_manager.py (1)
get_tool(65-70)
src/fastmcp/server/tasks/routing.py (6)
src/fastmcp/server/dependencies.py (2)
get_task_metadata(280-287)message(426-427)src/fastmcp/server/tasks/handlers.py (1)
submit_to_docket(30-142)src/fastmcp/prompts/prompt.py (1)
Prompt(118-322)src/fastmcp/server/server.py (1)
resource(2034-2177)src/fastmcp/resources/resource.py (2)
Resource(137-331)key(302-304)src/fastmcp/resources/template.py (2)
ResourceTemplate(97-298)key(267-269)
src/fastmcp/prompts/prompt.py (2)
src/fastmcp/exceptions.py (1)
PromptError(22-23)src/fastmcp/server/tasks/routing.py (1)
check_background_task(26-75)
src/fastmcp/server/proxy.py (3)
src/fastmcp/client/client.py (3)
read_resource(834-839)read_resource(842-849)read_resource(851-889)src/fastmcp/server/context.py (1)
read_resource(297-307)src/fastmcp/prompts/prompt.py (1)
PromptResult(73-115)
src/fastmcp/tools/tool.py (2)
src/fastmcp/utilities/types.py (2)
Audio(307-362)File(365-448)src/fastmcp/server/tasks/routing.py (1)
check_background_task(26-75)
src/fastmcp/resources/resource_manager.py (5)
src/fastmcp/server/proxy.py (1)
read_resource(188-219)src/fastmcp/client/client.py (3)
read_resource(834-839)read_resource(842-849)read_resource(851-889)src/fastmcp/server/middleware/tool_injection.py (1)
read_resource(98-103)src/fastmcp/server/context.py (1)
read_resource(297-307)src/fastmcp/resources/resource.py (1)
ResourceContent(39-134)
src/fastmcp/server/providers/fastmcp_provider.py (2)
src/fastmcp/server/dependencies.py (1)
get_context(271-277)src/fastmcp/prompts/prompt_manager.py (1)
get_prompt(55-60)
src/fastmcp/resources/resource.py (4)
src/fastmcp/resources/template.py (4)
convert_result(180-185)_read(187-219)_read(306-329)key(267-269)src/fastmcp/server/providers/fastmcp_provider.py (2)
_read(145-151)_read(326-375)src/fastmcp/server/tasks/routing.py (1)
check_background_task(26-75)src/fastmcp/client/tasks.py (4)
result(202-207)result(336-393)result(427-458)result(497-551)
src/fastmcp/resources/template.py (2)
src/fastmcp/resources/resource.py (7)
Resource(137-331)ResourceContent(39-134)convert_result(234-239)from_value(69-108)key(302-304)read(220-232)read(398-416)src/fastmcp/server/tasks/routing.py (1)
check_background_task(26-75)
🪛 Ruff (0.14.8)
src/fastmcp/prompts/prompt.py
246-246: Avoid specifying long messages outside the exception class
(TRY003)
src/fastmcp/server/server.py
1351-1351: Avoid specifying long messages outside the exception class
(TRY003)
1353-1353: Avoid specifying long messages outside the exception class
(TRY003)
1398-1398: Avoid specifying long messages outside the exception class
(TRY003)
1400-1400: Avoid specifying long messages outside the exception class
(TRY003)
1452-1452: Avoid specifying long messages outside the exception class
(TRY003)
1492-1494: Prefer TypeError exception for invalid type
(TRY004)
1492-1494: Avoid specifying long messages outside the exception class
(TRY003)
1495-1495: Consider moving this statement to an else block
(TRY300)
1597-1597: Avoid specifying long messages outside the exception class
(TRY003)
1615-1615: Avoid specifying long messages outside the exception class
(TRY003)
1616-1616: Avoid specifying long messages outside the exception class
(TRY003)
1677-1680: Prefer TypeError exception for invalid type
(TRY004)
1677-1680: Avoid specifying long messages outside the exception class
(TRY003)
1734-1734: Avoid specifying long messages outside the exception class
(TRY003)
src/fastmcp/server/providers/fastmcp_provider.py
256-256: Consider moving this statement to an else block
(TRY300)
327-327: Unused method argument: uri
(ARG002)
src/fastmcp/resources/template.py
307-307: Unused method argument: uri
(ARG002)
⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (4)
- GitHub Check: Run tests with lowest-direct dependencies
- GitHub Check: Run tests: Python 3.10 on windows-latest
- GitHub Check: Run tests: Python 3.10 on ubuntu-latest
- GitHub Check: Run tests: Python 3.13 on ubuntu-latest
🔇 Additional comments (44)
examples/providers/sqlite/server.py (4)
17-17: LGTM!The
Sequenceimport aligns with the updated return type annotation forlist_tools.
74-76: LGTM!Adding
super().__init__()ensures proper initialization of theProviderbase class, which is a best practice for inheritance.
78-83: LGTM!The signature change from
list_tools(self, context: Context) -> list[Tool]tolist_tools(self) -> Sequence[Tool]correctly aligns with the updatedProviderbase class interface insrc/fastmcp/server/providers/base.py(lines 150-155).
85-92: LGTM!The signature change removing the
contextparameter aligns with the new provider interface where components own their execution rather than providers. This matches the base class definition insrc/fastmcp/server/providers/base.py(lines 157-167).src/fastmcp/resources/resource_manager.py (2)
10-10: LGTM!The import is required for the
CreateTaskResulttype annotation in theread_resourcereturn type.
290-302: LGTM!The return type extension to
ResourceContent | mcp.types.CreateTaskResultenables propagation of background task results through the resource reading path. The docstring accurately documents both execution paths (synchronous and background). This aligns with the broader SEP-1686 background task protocol being implemented across the codebase.src/fastmcp/prompts/prompt_manager.py (2)
7-8: LGTM!The import is required for the
CreateTaskResulttype annotation in therender_promptreturn type.
106-120: LGTM!The return type extension to
PromptResult | mcp.types.CreateTaskResultis consistent with the parallel changes inResourceManager.read_resource. The docstring accurately documents both synchronous and background execution paths. Based on learnings, this is correctly applied across related Manager classes.src/fastmcp/server/proxy.py (2)
188-219: LGTM!The return type extension to
ResourceContent | mcp.types.CreateTaskResultcorrectly matches the parent class signature. The proxy fallback path appropriately returnsResourceContentsinceProxyResourceusestask_config=TaskConfig(mode="forbidden")(line 363), meaning proxy resources cannot be background tasks themselves.
257-276: LGTM!The return type extension to
PromptResult | mcp.types.CreateTaskResultcorrectly matches the parent class signature. Consistent with the resource proxy, the prompt proxy returnsPromptResultdirectly sinceProxyPromptusestask_config=TaskConfig(mode="forbidden")(line 534).src/fastmcp/server/dependencies.py (3)
43-51: LGTM!The two new
ContextVardeclarations for task metadata propagation are well-documented and appropriately typed. The comments clearly explain their purpose:
_task_metadatafor propagating task metadata through the async call stack_docket_fn_keyfor component Docket function lookup with namespace prefix
53-68: LGTM!The
__all__export list is correctly updated to includeget_task_metadata, making the new public API discoverable.
280-288: LGTM!The
get_task_metadata()function provides a clean public API for accessing the task metadata context variable. The docstring clearly explains the return semantics (dict for background task requests, None for normal execution). Note: The AI summary mentioned a duplicate definition, but only one definition exists in this file.src/fastmcp/server/tasks/protocol.py (1)
265-281: LGTM! Clean delegation to component conversion methods.The refactored resource and new template task type handling correctly delegate result conversion to the respective component's
convert_result()method, then convert to MCP format. This aligns well with the PR objective of having components own their execution/conversion logic.src/fastmcp/server/tasks/routing.py (1)
26-75: Well-designed centralized task routing logic.This consolidates the ~30 lines of duplicated background-task enforcement across Tool, Resource, Prompt, and ResourceTemplate into a single reusable function. The mode enforcement is clear and the error messages are descriptive.
One consideration:
METHOD_NOT_FOUNDis used for mode violations. This seems intentional per SEP-1686 semantics (the "method" doesn't exist in the requested mode), but verify this aligns with client expectations.src/fastmcp/tools/tool.py (3)
243-281: Comprehensive result conversion with good fallback handling.The
convert_result()implementation correctly:
- Passes through existing
ToolResultinstances- Handles special content types (ContentBlock, Audio, Image, File) without forcing structured content when no schema exists
- Gracefully falls back to content-only on serialization failures
- Respects
x-fastmcp-wrap-resultfor schema-driven wrappingThe logic flow is clear and handles edge cases appropriately.
283-306: Clean server entry point with proper task routing delegation.The
_run()method correctly integrates with the centralizedcheck_background_task()helper, resolving the function key from context or falling back toself.key. This pattern enables any Tool subclass to support background execution without code duplication.
314-335: Consistent add_to_docket signature extension across Tool and FunctionTool.Both implementations correctly:
- Accept new
fn_keyandtask_keykeyword-only parameters- Resolve
lookup_keywith fallback toself.key- Inject
task_keyas"key"in kwargs when providedThe difference in argument passing (positional vs splatted) between
ToolandFunctionToolis intentional and correctly documented—FunctionTool.fnexpects**kwargswhile the baseTool.runexpects a dict.Also applies to: 490-513
src/fastmcp/server/providers/base.py (2)
51-62: TaskComponents field types updated but get_tasks() filter preserved.The field type widening from
FunctionTool/etc toTool/etc inTaskComponentsimproves API flexibility whileget_tasks()(lines 244-275) correctly continues to filter for function-based implementations that can be registered with Docket. This is a sensible design.
72-81: Clear documentation of the new execution model.The updated docstring accurately reflects the refactored architecture: "Components execute themselves via run()/read()/render() - providers just source them." This aligns with the PR objective of moving execution responsibility to components.
src/fastmcp/prompts/prompt.py (3)
212-252: Solid convert_result() implementation with proper error handling.The conversion logic handles all expected input types (PromptResult, strings, PromptMessage, and JSON-serializable objects) with appropriate fallbacks.
Regarding the static analysis hint (TRY003): The inline message in
PromptErroron line 246 is acceptable here sincePromptErroris a simple exception class and the message provides useful context about the conversion failure. This is a minor style consideration.
254-293: Correct task routing integration in _render().The method properly:
- Resolves the function key from context variable or falls back to
self.key- Delegates to
check_background_task()for mode enforcement- Returns early with
CreateTaskResultfor background execution- Falls back to synchronous
render()with deprecation warning handlingThe return type annotation
PromptResult | mcp.types.CreateTaskResultaccurately reflects both execution paths.
301-322: Consistent add_to_docket extensions for Prompt and FunctionPrompt.Both implementations follow the same pattern as Tool:
- Accept
fn_keyandtask_keykeyword-only parameters- Resolve lookup key with fallback
- Inject task_key into kwargs
FunctionPromptcorrectly splats arguments as**kwargsto match its function's signature, while basePromptpasses arguments as a single positional argument.Also applies to: 526-549
src/fastmcp/resources/resource.py (4)
234-239: LGTM!The
convert_resultmethod correctly delegates toResourceContent.from_valuewith the resource'smime_type, providing a consistent conversion API that can be overridden by subclasses.
241-275: Well-structured task routing entry point.The
_readmethod cleanly separates concerns:
- Retrieves the docket function key from contextvar with fallback to
self.key- Delegates to
check_background_taskfor mode validation and background submission- Falls back to synchronous execution with deprecation handling
The deprecation warning for returning
str/bytesfromread()is preserved correctly.
312-331: LGTM!The
add_to_docketsignature extension withfn_keyandtask_keyparameters provides the flexibility needed for namespace-aware task scheduling. The logic correctly:
- Uses
fn_keyor falls back toself.keyfor function lookup- Passes
task_keyto docket via kwargs when provided
398-416: LGTM!
FunctionResource.readcorrectly callsself.convert_result(result)after handling awaitable results and recursiveResourcereads, ensuring consistent output conversion.src/fastmcp/resources/template.py (4)
180-185: LGTM!The
convert_resultmethod provides consistent conversion semantics matchingResource.convert_result, enabling template-specific mime_type handling.
187-219: Clean task routing implementation for ResourceTemplate.The method correctly:
- Uses a pattern check (
"{" not in key) to determine whether to use the contextvar or fall back toself.key- Delegates to
check_background_taskfor mode enforcement and background submission- Creates the resource and reads it synchronously when not backgrounded
- Uses
resource.convert_resultfor consistent output conversion
277-298: LGTM!The
add_to_docketsignature extension properly handlesfn_key/task_keyand passesparamsas a positional argument, matching the template's expected calling convention.
391-414: LGTM!
FunctionResourceTemplate.add_to_docketcorrectly splatsparamsas**kwargssince the underlying function expects keyword arguments. This differs from the baseResourceTemplatewhich passesparamsas a single positional dict.src/fastmcp/server/tasks/handlers.py (3)
30-56: Well-documented unified submission handler.The function signature and docstring clearly describe the generalized approach for all component types. The SEP-1686 compliance notes are helpful for understanding the design rationale.
77-88: Robust task key and metadata storage.The implementation correctly:
- Builds a structured task key with session/task/type/component info
- Stores the mapping in Redis with appropriate TTL buffer
- Stores creation timestamp separately for retrieval
The 15-minute TTL buffer ensures mappings outlive task executions.
106-114: Correct differentiation between Resource and other component types.Resources don't take arguments, so the branching at lines 111-114 correctly handles the different
add_to_docketsignatures. Thetype: ignorecomments are appropriate given the varying method signatures across component types.src/fastmcp/server/server.py (5)
1245-1297: Clean task metadata propagation pattern.The implementation correctly:
- Extracts task metadata from the MCP request context
- Sets both
_task_metadataand_docket_fn_keycontextvars before middleware execution- Resets contextvars in a
finallyblock to prevent leakage- Checks for
CreateTaskResultand returns it directly for background executionThis establishes a consistent pattern used throughout the handlers.
1304-1353: Proper custom handler for resource task support.Since the SDK's
read_resourcedecorator doesn't supportCreateTaskResultreturns, this custom handler correctly bypasses it while maintaining the same structure. The contextvar management mirrors_call_tool_mcp.
1486-1495: Defensive check for unexpected CreateTaskResult.The
RuntimeErrorat lines 1492-1494 guards against an invariant violation whereCreateTaskResultappears without task metadata being set. This is appropriate defensive coding since the direct_read_resource_mcppath shouldn't produce background tasks.
1599-1638: Well-factored execute methods for resources and templates.The separation of
_execute_resourceand_execute_templateprovides clear error handling boundaries while delegating task routing to the component's_readmethod. The error masking logic respects the server's_mask_error_detailssetting.
1665-1681: Appropriate RuntimeError for unexpected CreateTaskResult.The check at lines 1676-1680 correctly enforces that
_get_prompt_middlewareis only called in synchronous contexts. For task-augmented execution, callers should use_get_prompt_content_middlewaredirectly.src/fastmcp/server/providers/fastmcp_provider.py (5)
50-105: LGTM!
FastMCPProviderToolcorrectly wraps a tool and delegates execution to the child server's middleware via_call_tool_middleware. The_runmethod appropriately skips task handling at this layer since the underlying tool handles it.
153-183: Robust context handling for Docket worker scenarios.The
readmethod correctly handles two scenarios:
- Normal execution with existing context - delegates directly
- Docket worker execution without context - creates a temporary context
The comment about preserving
_docket_fn_keyis important for correct Docket lookup in nested mounts.
559-601: Correct approach: Return actual components for Docket registration.Returning the child's actual components (not wrapped) ensures their underlying functions get registered with Docket. The
TransformingProvider.get_tasks()handles namespace transformation of keys, which is the right separation of concerns.
480-493: LGTM!The
list_toolsandget_toolmethods correctly wrap returned tools asFastMCPProviderToolinstances, ensuring middleware execution when tools are called through the provider.
34-42: URI template expansion lacks protection against backslash sequences in valuesIn Python's re.sub(), backslash escapes in the replacement string are processed, and backreferences such as \1, \2 are replaced with substrings matched by groups in the pattern. The implementation
re.sub(rf"\{{{key}\}}", str(value), result)passesstr(value)directly as the replacement without escaping. Since Python 3.5, unmatched groups are replaced with an empty string, but if a value contains backslash followed by digits (e.g.,\1), it will still be interpreted as a backreference attempt. While this particular pattern has no capture groups, the approach is fragile.Consider using a replacement function with
re.sub()or escaping backslashes in values to prevent unintended escape sequence processing.
Test Failure AnalysisSummary: Test times out on Windows due to SQLite locking when creating OAuthProxy without isolated storage. Root Cause: The test creates an instance without providing a The stack trace shows the timeout occurs at: File "diskcache/core.py", line 623, in _con
con = self._local.con = sqlite3.connect(Suggested Solution: Provide an isolated in-memory storage for this test to avoid SQLite file contention:
Example fix: from key_value.aio.stores.memory import MemoryStore
async def test_callback_error_returns_html_page(self):
"""Test that OAuth callback errors return styled HTML instead of data: URLs."""
from unittest.mock import Mock
from starlette.requests import Request
from starlette.responses import HTMLResponse
from fastmcp.server.auth.oauth_proxy import OAuthProxy
from fastmcp.server.auth.providers.jwt import JWTVerifier
# Create a minimal OAuth proxy with isolated storage
provider = OAuthProxy(
upstream_authorization_endpoint="https://idp.example.com/authorize",
upstream_token_endpoint="https://idp.example.com/token",
upstream_client_id="test-client",
upstream_client_secret="test-secret",
token_verifier=JWTVerifier(
jwks_uri="https://idp.example.com/.well-known/jwks.json",
issuer="https://idp.example.com",
audience="test-client",
),
base_url="http://localhost:8000",
jwt_signing_key="test-signing-key",
client_storage=MemoryStore(), # Add this line
)
# ... rest of testDetailed AnalysisThe test was added/modified in this PR and exposed a Windows-specific issue that wasn't caught because:
Other tests in the file use the Related Files
|
Test Failure AnalysisSummary: Test Root Cause: The test creates an OAuthProxy instance without providing a The stack trace shows the timeout occurs at: File "diskcache/core.py", line 623, in _con
con = self._local.con = sqlite3.connect(Suggested Solution: Provide an isolated in-memory storage for this test to avoid SQLite file contention:
Example fix: from key_value.aio.stores.memory import MemoryStore
async def test_callback_error_returns_html_page(self):
"""Test that OAuth callback errors return styled HTML instead of data: URLs."""
from unittest.mock import Mock
from starlette.requests import Request
from starlette.responses import HTMLResponse
from fastmcp.server.auth.oauth_proxy import OAuthProxy
from fastmcp.server.auth.providers.jwt import JWTVerifier
# Create a minimal OAuth proxy with isolated storage
provider = OAuthProxy(
upstream_authorization_endpoint="https://idp.example.com/authorize",
upstream_token_endpoint="https://idp.example.com/token",
upstream_client_id="test-client",
upstream_client_secret="test-secret",
token_verifier=JWTVerifier(
jwks_uri="https://idp.example.com/.well-known/jwks.json",
issuer="https://idp.example.com",
audience="test-client",
),
base_url="http://localhost:8000",
jwt_signing_key="test-signing-key",
client_storage=MemoryStore(), # Add this line
)
# ... rest of testDetailed AnalysisThe test was added/modified in this PR and exposed a Windows-specific issue that wasn't caught because:
Other tests in the file use the Related Files
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This refactor moves task routing logic from Provider into the component classes themselves.
Key changes:
Providers source, components execute: Provider no longer has
call_tool(),read_resource(), etc. - it only lists and looks up components. Components handle their own execution viarun(),read(),render(). This is to avoid two potentially-conflicting ways to do the same thing (e.g. run a tool). Execution logic should be contained on a tool subclass.Unified task routing: New
check_background_task()inrouting.pyconsolidates the duplicated task mode enforcement logic that was copy-pasted acrossTool._run(),Resource._read(),Prompt._render(), andResourceTemplate._read().convert_result()as instance methods: Moved from standalone functions (convert_to_tool_result(result, tool)) to instance methods (tool.convert_result(result)) on base classes, enabling subclass customization.Wrapper components for middleware chains:
FastMCPProviderTool,FastMCPProviderResource, etc. wrap components to delegate execution through nested server middleware.This closes arguably a significant issue with the previous background implementation: it avoided all middleware. Now, background tasks are appropriately passed through all (potentially nested) middleware stacks.