Reference Issues/PRs

Independence: This PR is rebased on latest main and does not depend on any other open PR. It can be merged on its own.

Note: If #472 merges first, the standalone instantiate_pipeline MCP tool will already be removed. This PR still removes the validate_pipeline tool and ensures composition validation runs during pipeline instantiation.

What does this implement/fix? Explain your changes.

Removes the standalone validate_pipeline MCP tool. Pipeline composition validation already runs inside executor.instantiate_pipeline, so calling instantiate_pipeline (or instantiate_estimator with components after #472) automatically validates before registering a handle.

Changes:

• Removed validate_pipeline tool schema and routing from server.py
• Added test_pipeline_composition_check in tests/test_param_validation.py — invalid compositions (e.g. chaining forecasters) return success: False with validation diagnostics

Files changed (2):

• src/sktime_mcp/server.py
• tests/test_param_validation.py

Does your contribution introduce a new dependency? If yes, which one?

No.

What should a reviewer concentrate their feedback on?

• Confirm validate_pipeline is no longer registered as an MCP tool
• Verify invalid pipeline instantiation fails with validation_errors in the response

Any other comments

Rebased on latest main (1 commit, +8 / −22). 182 tests pass under make check.

PR checklist

For all contributions

• I've added unit tests and made sure they pass locally (make check).