Stop duplicating path parameter descriptions into tool prose

[jlowin]

format_simple_description was copying path parameter names and descriptions into the tool's prose description field, even though those details already exist in inputSchema. This created a problem: when ToolTransform hides a parameter (removing it from inputSchema), the stale reference in the description remained, confusing LLMs with a parameter they couldn't actually use.

The fix removes format_simple_description entirely — it was duplicating information that inputSchema already carries. Parameter descriptions, types, and required flags all live in inputSchema, which is also where transforms operate, so hiding a parameter now naturally removes all traces of it.

mcp = FastMCP.from_openapi(openapi_spec=spec, client=http_client)

# Before: description = "Get user\n\n**Path Parameters:**\n- **version**: API version"
# After:  description = "Get user"
# inputSchema always had: {"version": {"type": "string", "description": "API version"}}

Fixes #3130

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Keep format_simple_description importable for compatibility

Removing format_simple_description from the public OpenAPI utilities API introduces a backwards-incompatible runtime break: existing integrations that do from fastmcp.utilities.openapi import format_simple_description (or import it from ...openapi.formatters) will now fail with ImportError immediately after upgrade. Even if provider code no longer uses it, this symbol was previously exported and documented, so it should remain as a deprecated shim to avoid breaking downstream code unexpectedly.

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[coderabbitai]

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Walkthrough

This pull request removes the format_simple_description function from the public API and modifies how OpenAPI tool descriptions are constructed. The function, which previously appended parameter and request body details to base descriptions, is deleted from the formatters module and its imports across the codebase. Tool descriptions in the OpenAPI provider now use base descriptions directly. Documentation is updated with anchor references and notes regarding fallback behaviors in background task contexts.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/openapi-path-param-description

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