Files
Luigi Pederzani b45d9663ec feat(python): introduce roots support in MCPClient and Server (#751)
* fix(python): expose client capabilities to MCP servers

Add list_roots_callback support to Python connectors to properly
advertise the roots capability during MCP initialization handshake.

Previously, the Python library was not exposing any client capabilities
because the list_roots_callback was not being passed to ClientSession.
This fix ensures the roots capability is always advertised, bringing
the Python library in line with the TypeScript implementation.

Changes:
- Add roots and list_roots_callback params to BaseConnector
- Add get_roots() and set_roots() methods for managing roots
- Pass list_roots_callback to ClientSession in all connectors
- Export Root type from connectors module
- Update unit tests to expect list_roots_callback parameter

Closes MCP-1063

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat(python): add roots and list_roots_callback params to connectors

- Add roots and list_roots_callback parameters to StdioConnector,
  HttpConnector, and SandboxConnector constructors
- Add comprehensive unit tests for client capabilities exposure
- Tests verify roots capability, get_roots(), set_roots(), and
  that all callbacks are correctly passed to ClientSession

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* chore: fix import sorting and update API documentation

- Fix import sorting in test_client_capabilities.py (ruff)
- Regenerate API documentation for updated connector classes

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

* feat(python): add list_roots() method to server Context

Allow MCP servers to request the list of roots from connected clients
via ctx.list_roots(). This follows the same pattern as ctx.sample()
and ctx.elicit() for server-to-client requests.

* feat(python): add roots params to MCPClient and config

- Add roots and list_roots_callback parameters to MCPClient.__init__,
  from_dict(), and from_config_file() methods
- Update create_connector_from_config() to pass roots params to all
  connector types (Stdio, HTTP, Sandbox)
- Allows clients to configure roots at the MCPClient level and have
  them propagate to all sessions

* test(python): add get_client_roots tool to primitive server

Add a tool that demonstrates the roots capability by requesting and
returning the list of roots from the connected client. Used for
integration testing of the roots feature.

* test(python): add integration tests for roots capability

Add comprehensive integration tests for the roots feature:
- test_roots_capability: Verify server can request/receive roots
- test_roots_empty_by_default: Verify empty roots when not provided
- test_roots_with_custom_callback: Verify custom callback precedence
- test_set_roots_updates_server_view: Verify dynamic root updates

* test(python): update unit tests for roots parameters

Update mock assertions in test_client.py to expect the new roots
and list_roots_callback parameters in create_connector_from_config
calls.

* ci(python): add roots to primitive tests and README badge

- Add roots to CI workflow primitive test matrix
- Add roots to PR comment report primitives list
- Add Roots badge to README Primitives row

* feat(docs): enhance MCP client and server documentation for roots feature

- Added `roots` and `list_roots_callback` parameters to MCP client initialization documentation.
- Updated `create_connector_from_config` documentation to include new parameters.
- Introduced `list_roots` method documentation in server context, detailing its usage and return values.
- Improved overall clarity and completeness of API reference for better developer guidance.

* feat(python): add get_client_roots tool to context example

- Introduced a new tool, `get_client_roots`, to the context example, demonstrating how to retrieve and display the list of roots exposed by the client.
- Updated documentation to include the new tool and its functionality, enhancing the example's coverage of context features.

* feat(docs): add roots documentation for client and server

- Introduced new documentation for the `roots` feature, detailing how clients can expose file system roots to MCP servers and how servers can access these roots.
- Added examples for configuring roots in the MCP client and using the `list_roots()` method in the server context.
- Enhanced overall clarity and usability of the documentation to support developers in implementing the roots functionality.

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Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: pietrozullo <pietro.zullo@gmail.com>
2026-01-12 11:16:09 +01:00

9.2 KiB