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Troubleshooting a 400 Bad Request

A 400 Bad Request explicitly indicates that the HasMCP server could not understand or process your API request due to invalid syntax or an inappropriately formatted payload.

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Common Causes

In the HasMCP architecture, 400 Bad Request almost exclusively occurs during POST or PATCH operations where your request body structurally violates the required OpenAPI schema:
  1. Malformed JSON: Missing brackets, trailing commas, or invalid string escaping.
  2. Missing Required Fields: Attempting to create a Provider without explicitly passing the namespace property.
  3. Invalid Data Types: Passing an integer where a string is expected (e.g., "port": "5432" instead of "port": 5432).
  4. Invalid Enumerations: Submitting "type": "PLAIN" for a variable when only "ENV" or "SECRET" are permitted.

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Resolution Steps

  1. Check the Body Payload: Review your request against the official HasMCP OpenAPI specification.
  2. Read the Error Message: HasMCP uniquely returns specific validation errors (e.g. validation_error: 'namespace' cannot be empty) inside the payload when a 400 triggers.
  3. Verify JSON Integrity: Ensure your JSON is perfectly formatted before executing the automation script.