* feat(mcp): support custom tool interceptors via extensions_config.json
Add a generic extension point for registering custom MCP tool
interceptors through `extensions_config.json`. This allows downstream
projects to inject per-request header manipulation, auth context
propagation, or other cross-cutting concerns without modifying
DeerFlow source code.
Interceptors are declared as Python callable paths in a new
`mcpInterceptors` array field and loaded via the existing
`resolve_variable` reflection mechanism:
```json
{
"mcpInterceptors": [
"my_package.mcp.auth:build_auth_interceptor"
]
}
```
Each entry must resolve to a no-arg builder function that returns an
async interceptor compatible with `MultiServerMCPClient`'s
`tool_interceptors` interface.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* test(mcp): add unit tests for custom tool interceptors
Cover all branches of the mcpInterceptors loading logic:
- valid interceptor loaded and appended to tool_interceptors
- multiple interceptors loaded in declaration order
- builder returning None is skipped
- resolve_variable ImportError logged and skipped
- builder raising exception logged and skipped
- absent mcpInterceptors field is safe (no-op)
- custom interceptors coexist with OAuth interceptor
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* Potential fix for pull request finding
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
* fix(mcp): validate mcpInterceptors type and fix lint warnings
Address review feedback:
1. Validate mcpInterceptors config value before iterating:
- Accept a single string and normalize to [string]
- Ignore None silently
- Log warning and skip for non-list/non-string types
2. Fix ruff F841 lint errors in tests:
- Rename _make_mock_env to _make_patches, embed mock_client
- Remove unused `as mock_cls` bindings where not needed
- Extract _get_interceptors() helper to reduce repetition
3. Add two new test cases for type validation:
- test_mcp_interceptors_single_string_is_normalized
- test_mcp_interceptors_invalid_type_logs_warning
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(mcp): validate interceptor return type and fix import mock path
Address review feedback:
1. Validate builder return type with callable() check:
- callable interceptor → append to tool_interceptors
- None → silently skip (builder opted out)
- non-callable → log warning with type name and skip
2. Fix test mock path: resolve_variable is a top-level import in
tools.py, so mock deerflow.mcp.tools.resolve_variable instead of
deerflow.reflection.resolve_variable to correctly intercept calls.
3. Add test_custom_interceptor_non_callable_return_logs_warning to
cover the new non-callable validation branch.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* docs(mcp): add mcpInterceptors example and documentation
- Add mcpInterceptors field to extensions_config.example.json
- Add "Custom Tool Interceptors" section to MCP_SERVER.md with
configuration format, example interceptor code, and edge case
behavior notes
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: IECspace <IECspace@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
IECspace
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