Claude Code API Error 400 bad request: common causes

The error text

API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"..."}}

Match the message

Step-by-step fix

1. 1. Read the message

   The text after invalid_request_error names the problem. Match it in the table above.

2. 2. Reset model overrides

   Remove ANTHROPIC_MODEL and other model overrides from settings.json, restart, and choose a model with /model.

   ~/.claude/settings.json

   {
     "env": {
       "ANTHROPIC_AUTH_TOKEN": "YOUR_API_KEY",
       "ANTHROPIC_API_KEY": "",
       "ANTHROPIC_BASE_URL": "https://api.aicodewith.ai"
     }
   }

3. 3. Shrink the context

   Run /compact. If the session is very long, /clear and continue in a fresh one.

Are failed requests charged?

Failed requests (4xx/5xx, timeouts, dropped connections) are not charged — you're only billed for requests that complete successfully. If an upstream failure is automatically retried and succeeds, you're billed once.

Still failing?

• •Check the model's page on aicodewith: it shows recent health for each channel.
• •Look up the request in your dashboard usage records to see its model, status and cost.
• •Email support@aicodewith.com with the time of the error, the model and the error text (never your full API key).

Model status and pricesContact supportDocs

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