The Powerduck Blog

API engineering, from the spec out

Product updates, engineering notes, and guides for designing, debugging, testing, mocking, and serving MCP tools from one OpenAPI spec.

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ai 3 min read

Your Agent Added Types — Most of Them Are `any`

Type checking goes green, the CI badge turns green, and nobody notices the agent widened half the signatures to `any` to get there. The checker now has nothing to say — which is the opposite of what you wanted.

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AI Agents 4 min read

When Your Agent Summarizes Your Codebase, It Quietly Drops the Types

An agent reads your file, writes a summary for the next session, and in that paraphrase the generic constraint, the discriminated union, the branded ID all collapse into a vague noun. The next session then builds on a version of your code that never existed.

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