* feat: handle error from the initialize middleware
In some situation, the initialize middleware can check the status of the
server and decide to raise an error.
Example use case: in a FastMCPProxy, an initialization middleware
overrides the on_initialize method and connect to the underlying proxied
client. When client respond with error, I want to pass this error to the
client.
* docs update
* test: use McpError assertions now that exception propagation is fixed
- Update tests to catch McpError specifically instead of generic Exception
- Remove commented-out code in low_level.py
---------
Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
* Add comprehensive documentation for read-only tool patterns
Created new patterns guide explaining readOnlyHint annotation usage,
including practical examples, client-specific behavior, and best
practices for marking tools as read-only.
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Co-authored-by: William Easton <strawgate@users.noreply.github.com>
* Reorganize read-only tools docs into tools section
Moved read-only tools documentation from standalone patterns page into the tools.mdx file as a "Using Annotation Hints" subsection. Condensed from 218 lines to ~50 lines focusing on practical usage while maintaining essential information about readOnlyHint and other annotations.
Changes:
- Added "Using Annotation Hints" subsection in tools.mdx after MCP Annotations
- Removed docs/patterns/read-only-tools.mdx
- Updated docs.json navigation to remove patterns entry
- Content now positioned as core tool feature rather than advanced pattern
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Co-authored-by: Bill Easton <strawgate@users.noreply.github.com>
---------
Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
* SEP-1330 enum schema support for elicitation
* Add version badges for 2.14.0 elicitation features
* Fix Context.elicit() to handle SEP-1330 enum syntaxes
* Guard against empty list in elicit response_type
* Add guards for empty dict/list edge cases in elicit
* Refactor elicit: extract parsing and response handling to elicitation.py
* Add EventStore and SSE polling support (SEP-1699)
* Add close_sse_stream() method to Context
* Add SSE polling documentation
* Fix missing Context import in docs example
* Remove EventStore from root __init__.py, update docs imports
- Removed EventStore import and export from src/fastmcp/__init__.py
- Updated docs to import EventStore from fastmcp.server.event_store
- Resolves merge conflict by not exporting EventStore from root package
The task protocol (SEP-1686) is now always enabled - server always
registers task handlers and advertises task capabilities. Users still
opt into background execution at the server level (tasks=True) or
component level (task=True on tools, prompts, resources).
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Co-Authored-By: Claude <noreply@anthropic.com>
Replace custom VersionBadge implementation with Mintlify's native Badge component while preserving custom color and border styling via CSS. This leverages Mintlify's built-in sizing, typography, and icon support while maintaining the original visual design.
- Lead with concepts instead of code
- Explain MCP background tasks vs general Python concurrency
- Document Docket's Prefect origins and battle-tested infrastructure
- Add sections on graceful degradation and embedded workers
- Fix version badge to 2.14.0
- Link to SEP-1686 spec
Docket provides background task execution and is now always available
for all FastMCP servers. Only `enable_tasks` remains to control the
SEP-1686 task protocol support.
Changes:
- Remove `enable_docket` setting and related validation
- Docket/Worker lifecycle is always active in server lifespan
- CurrentDocket and CurrentWorker dependencies work without config
- Add server readiness signaling via `_started` event
- Fix test timing issues with proper port probing
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Co-Authored-By: Claude <noreply@anthropic.com>
* Implement MCP background tasks (SEP-1686) using Docket
Adds support for background task execution via the MCP task protocol,
powered by Docket for task queue management.
- Tools, resources, and prompts can be marked with `task=True` to run async
- Progress dependency for tracking task progress
- CurrentDocket and CurrentWorker dependencies for advanced use cases
- Client API with `.call_tool(..., task=True)` returns task handles
- Task status notifications via subscriptions
- CLI worker command for distributed task processing
Configuration via environment:
- FASTMCP_ENABLE_DOCKET=true
- FASTMCP_ENABLE_TASKS=true
- FASTMCP_DOCKET_URL=redis://... (or memory:// for single-process)
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Co-Authored-By: Claude <noreply@anthropic.com>
* Fix tasks example import (TaskStatusResponse → GetTaskResult)
The example was using a non-existent TaskStatusResponse type.
Updated to use mcp.types.GetTaskResult which is what the
on_status_change callback actually receives.
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Co-Authored-By: Claude <noreply@anthropic.com>
* Fix env var name in Docket error messages
The error messages referenced FASTMCP_EXPERIMENTAL_ENABLE_DOCKET but the
actual setting is FASTMCP_ENABLE_DOCKET.
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Co-Authored-By: Claude <noreply@anthropic.com>
* Remove deprecated code re-added from pre-#2329 branch
- Remove ExtendedEnvSettingsSource (FASTMCP_SERVER_ prefix support)
- Remove dependencies parameter from FastMCP.__init__
* Replace fakeredis git pin with PyPI release
* Remove redundant fakeredis dev dep (pulled via pydocket)
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
* Fix RFC 8414 path-aware authorization server metadata discovery
Override get_well_known_routes() in OAuthProvider to rewrite the
authorization server metadata route to be path-aware based on issuer_url,
matching how protected resource metadata already works.
Closes#2527
* Update readme
* Initialize 2.14 deprecation removal branch
* Remove deprecated FASTMCP_SERVER_ environment variable prefix (#2330)
* Remove deprecated Context.get_http_request method (#2332)
* Remove fastmcp.Image top-level import (deprecated 2.8.1) (#2334)
* Remove test warnings (#2331)
* Create new branch and fix issue
* Remove deprecated client parameter from FastMCPProxy (#2333)
* Remove deprecated run_streamable_http_async method (#2338)
* Remove deprecated sse_app method (#2337)
* Remove deprecated run_sse_async method (#2335)
* Remove deprecated run_sse_async method
* Update CLI and tests to use run_http_async(transport="sse")
- Change CLI to call run_http_async with transport="sse" instead of run_sse_async
- Update test to mock run_http_async with create=True for v1 servers
* Revert CLI changes - v1 servers do have run_sse_async
- Keep CLI calling run_sse_async() for v1 compatibility
- Update test to mock run_sse_async (which exists on v1)
* Remove unnecessary type ignore for run_sse_async
Method exists on v1 FastMCP class, no type error
* Remove unused imports after test deletion
* Remove deprecated streamable_http_app method (#2336)
* Remove deprecated dependencies parameter from FastMCP constructor (#2340)
* Remove output_schema=False support (deprecated 2.11.4) (#2339)
* Remove deprecated client parameter from FastMCPProxy (#2333)
* Delete deprecated test_output_schema_false.py
Tests functionality that has been removed
* Remove deprecated BearerAuthProvider module (#2341)
* Remove resource_prefix_format="protocol" support (deprecated 2.4.0) (#2342)
* Remove resource_prefix_format="protocol" support (fixes#2195)
Removes deprecated protocol format (prefix+resource://path) and keeps only
path format (resource://prefix/path). Since only one format remains:
- Removed resource_prefix_format from settings, FastMCP.__init__, and helpers
- Simplified add_resource_prefix, remove_resource_prefix, has_resource_prefix
- Removed MountedServer.resource_prefix_format field
- Deleted tests for protocol format
All resource prefixes now use path format exclusively.
* Clean up resource_prefix_format references
- Remove from test files
- Update documentation to remove protocol format section
- Move custom HTTP routes note to mounting section
- Remove resource_prefix_format from settings docs
* Use inline version note instead of badge for prefix format
* Remove obsolete test functions and update docs
- Delete test functions that no longer assert anything
- Remove proxy.mdx reference to deleted prefix format section
* Format error messages per ruff
* Remove from_client classmethod (deprecated 2.8.0) (#2343)
* Remove deprecated from_client classmethod (fixes#2192)
* Remove unused Client import
* Remove add_resource_fn method (deprecated 2.7.0) (#2345)
* Update SDK
* Add missing imports for exclude_args deprecation warning
* Fix Azure provider to handle OIDC scopes correctly
OIDC scopes (openid, profile, email, offline_access) were being
incorrectly prefixed with identifier_uri, causing Azure to reject
authorization requests. This fix:
- Detects OIDC scopes and sends them unprefixed to Azure
- Filters OIDC scopes from token validation (Azure doesn't include
them in access token scp claims)
- Still advertises OIDC scopes to clients via valid_scopes
- Also handles dot-notation scopes (e.g., User.Read) correctly
Fixes#2451, #2420
* Fix dot-notation scopes to be prefixed (custom scopes can have dots)
* Improve Azure scope handling docs with clear examples
* Add consent_csp_policy parameter to OAuthProxy
Allows customization or disabling of CSP directives on the consent page.
Fixes#2476.
* Add consent_csp_policy to OIDCProxy and update docs
* Fix HTML injection vulnerability in CSP policy
HTML-escape the CSP policy value before inserting into meta tag to prevent HTML injection when CSP policies contain quotes.
Corrects the typo in the VersionBadge component in docs/servers/icons.mdx. The version number was incorrectly displayed as 2.14.0 but should be 2.13.0 to match the actual current version of FastMCP.
Fixes issue #2487
* sk-provider updates - aud not enforce, scopes enforce if present
* updating env_prefix, adding debug logs
* updating docs
* ruff formatting
* not changing prefix for backward compatiblity
* backward compatibility changes
* give more preference to base_url than mcp_url if both passed
* updating docs
* refactor
* updating example server
* updating readme of example
* updating docs
* updating tests to reflect what should ideally go in the parameter
Fixes issue #2431 where exclude_args fails when excluded parameters have
non-serializable types (e.g., ServerSession). The fix excludes parameters
from function annotations before Pydantic tries to serialize them.
Also adds deprecation notice that exclude_args will be deprecated in
FastMCP 2.14 in favor of dependency injection.
The on_initialize hook (2.13.0) runs before the MCP session is established, causing request_context
to be unavailable. Changed request_context to return None instead of raising, allowing middleware to
check availability and use HTTP helpers when needed. Updated docs to guide this pattern.
Closes#2393
* docs: clarify pytest-asyncio dependency and asyncio mode configuration
Added a Prerequisites section to the testing documentation explaining:
- pytest-asyncio is required for async test functions and fixtures
- Recommended configuration: asyncio_mode = 'auto' in pyproject.toml
- This eliminates need for @pytest.mark.asyncio decorators
Resolves#2372
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
* feat: add testing_demo example with comprehensive test suite
Add a standalone example project demonstrating FastMCP testing patterns:
- Tools, resources, and prompts with full test coverage
- pytest-asyncio configuration in pyproject.toml
- 18 passing tests showing async fixtures, parametrized tests, and more
- Documentation explaining testing best practices
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
---------
Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
* Add manual initialization control to Client
- Add auto_initialize parameter (default True) to control automatic initialization
- Make initialize() method public with idempotent caching
- Add comprehensive test suite for initialization behavior
* Document client initialization control and server instructions
- Expand documentation to cover auto_initialize parameter
- Show manual initialization for advanced use cases
- Document accessing server instructions via initialize_result
* Update client.mdx
* switch from pre-commit to prek
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Co-Authored-By: Claude <noreply@anthropic.com>
* fix prek tools list in contributing.mdx - include prettier, not pytest
* Use prek-action for caching
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
- Restructured confusing sections: 'Object-like Results' → 'Dictionaries and Objects', 'Non-object Results' → 'Primitives and Collections', 'Complex Type Example' → 'Typed Models'
- Simplified CodeGroup examples to show Tool Definition + MCP Result instead of 3-4 confusing tabs
- Split Primitives/Collections into separate CodeGroups for clarity
- Renamed 'Full Control with ToolResult' → 'ToolResult and Metadata' for better TOC visibility
- Flattened ToolResult documentation with inline field descriptions instead of nested headings
- Added version badge for ToolResult meta field (2.13.1)
- Added clarification that ToolResult meta is separate from @mcp.tool meta
- Improved example server with realistic metadata (execution time, character/word counts)
- Fixed code formatting (multi-line objects, trailing commas)
* Add meta to ToolResult
* add this at the client level and test the full integration
* add example
* slipped through linting somehow
---------
Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
* Added to_data_uri method and path_to_data_uri classmethod for Image class.
* Removed path_to_data_uri classmethod and modified _get_mime_type to use mimetypes.guess_type function instead of hardcoded dictionary.
* Register image/webp with mimetypes before guess_type to support WEBP mimetype detection on Python 3.10.
* Improved branch coverage for Image.to_data_uri.
* Added Image._to_data_uri example in the docs.
