Each MCP tool passes solo tests, but the agent's full workflow breaks on state passing
Stock-Pumpkin-8859 · reddit · 2026-09-21
Testing a simple create→fetch→update MCP workflow, every tool passed individually — valid schemas, expected API responses. But when the agent ran the full chain, the second call never received the record ID from the first, improvised another lookup path, and derailed. The failure mode is state passing between calls, not tool availability. The author asks how others test this.
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