* 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
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Co-authored-by: Jeremiah Lowin <153965+jlowin@users.noreply.github.com>
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
* Add compatibility tools contrib module
Implements four standalone tools that expose resources and prompts
as callable tools for clients that only support the tools capability.
Features:
- list_resources: List all available resources
- get_resource: Read a resource by URI
- list_prompts: List all available prompts
- get_prompt: Get a prompt with optional arguments
The tools use Context to access the server instance and can be easily
added to any FastMCP server using the add_compatibility_tools helper
or by adding individual tool instances directly.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
* Simplify compatibility tools to return raw MCP protocol objects
Return raw MCP protocol objects (ListResourcesResult, ReadResourceResult,
ListPromptsResult, GetPromptResult) instead of custom dictionaries. This
makes the tools simpler and more predictable by directly exposing what
the client methods return.
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
* Add tool injection middleware
* cleanup contrib module
* More clean-up
* Clean up tool injection middleware.
* Update src/fastmcp/server/middleware/tool_injection.py
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Add tool injection docs
* Small cleanup of prompt middleware
* PR Feedback
* Fix tool injection tests
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Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: William Easton <strawgate@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Catch more openapi changes
* Simplify middleware list operations to use lists directly
- Updated middleware signatures to work with list[Tool], list[Resource], etc instead of wrapper objects
- Removed unnecessary ListToolsResult, ListResourcesResult wrapper types
- Updated documentation to show simpler list-based filtering pattern
- Added tests for list-based middleware filtering
Closes#1121🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
---------
Co-authored-by: Claude <noreply@anthropic.com>
Implements timing, logging, rate limiting, and error handling middleware to showcase
FastMCP's middleware capabilities as a headline feature. Each middleware includes:
- Production-ready implementations with full configurability
- Comprehensive unit and integration tests with real FastMCP servers
- Updated documentation with teaching examples and production usage patterns
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
