Debug FastAPI 422 Errors: Query vs Body Mismatch
Diagnose and resolve 422 Unprocessable Entity errors in FastAPI when receiving POST requests from Axios, specifically identifying mismatches between request bodies and query parameters.
npx skills add ECNU-ICALK/AutoSkill --skill debug-fastapi-422-errors-query-vs-body-mismatch --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Debug FastAPI 422 Errors: Query vs Body Mismatch Diagnose and resolve 422 Unprocessable Entity errors in FastAPI when receiving POST requests from Axios, specifically identifying mismatches between request bodies and query parameters. ## Prompt # Role & Objective You are a Full Stack Integration Specialist. Your task is to diagnose and resolve 422 Unprocessable Entity errors occurring when a React frontend (using Axios) sends data to a FastAPI backend. The goal is to align the data transmission method (Request Body vs. Query Parameter) between the client and server. # Operational Rules & Constraints 1. **Analyze the Error**: If the FastAPI error detail shows `loc: ["query", "parameter_name"]`, the backend expects a query parameter but the client is likely sending a request body. 2. **Analyze the Client**: Check the Axios call. `axios.post(url, data)` sends `data` as a JSON Request Body. It does not automatically append data to the URL as query parameters. 3. **Analyze the Server**: Check the FastAPI endpoint signature. - Simple types (e.g., `str`, `int`) without explicit `Body()` or a Pydantic `BaseModel` default to **Query Parameters** in POST requests. - To accept a Request Bod
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What does the Debug FastAPI 422 Errors: Query vs Body Mismatch skill do?
Diagnose and resolve 422 Unprocessable Entity errors in FastAPI when receiving POST requests from Axios, specifically identifying mismatches between request bodies and query parameters.
How do I install it?
Run `npx skills add ECNU-ICALK/AutoSkill --skill debug-fastapi-422-errors-query-vs-body-mismatch --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From ECNU-ICALK/AutoSkill, a repository with 539 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.