feat: add outputSchema support for local MCP tools - #10901
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This pull request introduces support for outputSchema in local MCP tools, updating the ServerTool interface, the tool builder function, and associated tests. The reviewer feedback suggests simplifying the ServerTool interface by removing the unused OutputSchema generic parameter to avoid a phantom type parameter, and updating the tool function signature accordingly.
joehan
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Aug 7, 2026
### Description Introduced the `outputSchema` property to the MCP `ServerTool` interface and the `tool()` builder function, enabling local tools to declare typed output schemas. Since the `@modelcontextprotocol/sdk` natively supports `outputSchema`, remote server schemas are automatically validated and forwarded. ### Scenarios Tested - Verified that local tools constructed using `tool()` builder accept and compile with `outputSchema`. - Verified that `outputSchema` gets processed and cleaned correctly in unit tests. - Verified that `OneMcpServer.listTools()` successfully parses and retains the `outputSchema` returned by remote servers. ### Sample Commands npx mocha src/mcp/tool.spec.ts src/mcp/onemcp/onemcp_server.spec.ts
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Description
Introduced the
outputSchemaproperty to the MCPServerToolinterface and thetool()builder function, enabling local tools to declare typed output schemas. Since the@modelcontextprotocol/sdknatively supportsoutputSchema, remote server schemas are automatically validated and forwarded.Scenarios Tested
tool()builder accept and compile withoutputSchema.outputSchemagets processed and cleaned correctly in unit tests.OneMcpServer.listTools()successfully parses and retains theoutputSchemareturned by remote servers.Sample Commands
npx mocha src/mcp/tool.spec.ts src/mcp/onemcp/onemcp_server.spec.ts