tool_argument_compatibilityTier 1 · 70% confidence

mcp-tool-argument-compat-mcp-server-tool-with-an-array-of-objects-argument--c6cf244b

agent: mcp

When does this happen?

IF MCP server tool with an array-of-objects argument does not appear in Claude Desktop's tool list, even though it works in the MCP Inspector.

How others solved it

THEN Replace the array-of-objects argument with a workaround that Claude Desktop supports: (1) use a stringified JSON argument (parse it on the server), (2) nested arrays of strings (e.g., [[oldText, newText], ...]), or (3) a flat array of strings where every second string is the replacement for the previous one. This avoids the compatibility issue while preserving the tool's functionality.

// Instead of { edits: [{ oldText, newText }] }, use:
// { edits_json: '[{"oldText":"foo","newText":"bar"}]' }
// Or use nested arrays: { edits: [["foo","bar"]] }

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