feat: add optional outputSchema support for tool specifications

[vamgan]

This PR adds support for MCP output schema tool specifications as defined in the MCP specification (https://modelcontextprotocol.io/specification/2025-06-18/server/tools#data-types). This allows tools to define their expected output structure through outputSchema, which is particularly valuable for LLM agents to better understand tool capabilities and responses.

Note, the LLM is not automatically shown the outputSchema. In the future certain models may accept but. But for now, it is a device that users can leverage internally. For example if someone wanted to create their own dynamic tool loader they could use the outputSchema as a message.

As part of this we needed to make sure the BedrockModel explicitly manages its supported fields (including handling outputSchema appropriately), while other providers naturally drop fields they don't recognize. This maintains backward compatibility while keeping the code cleaner and more maintainable.

Closes #787

Type of Change

New feature

Testing

How have you tested the change? Verify that the changes do not break functionality or introduce warnings in consuming repositories: agents-docs, agents-tools, agents-cli

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

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[dbschmigelski]

Thanks for the work here!

[mxie-extreme]

Should we add outputSchema here too: https://github.com/strands-agents/sdk-python/blob/main/src/strands/tools/mcp/mcp_agent_tool.py#L63

[vamgan]

Should we add outputSchema here too: https://github.com/strands-agents/sdk-python/blob/main/src/strands/tools/mcp/mcp_agent_tool.py#L63

yes, thanks for pointing it out.

[dbschmigelski]

Hi, I want to apologize for the delay in reviewing this. I will take a look tomorrow morning with the aim of getting the PR merged next week.

[vamgan]

Hi, I want to apologize for the delay in reviewing this. I will take a look tomorrow morning with the aim of getting the PR merged next week.

Thanks!

[vamgan]

@dbschmigelski Hi,any issues for this merge?

[dbschmigelski]

Hi, turns out #836 was not as relevant. Or rather it did not go far enough. We still were coupled to the ToolSpec definition. This PR removes that by doing the destructuring in BedrockModel. Meaning we do not need the global filter in the event loop.

All other providers drop the additional field.