Error Codes - SAMVAD

All protocol errors are returned as a response envelope with "status": "error" and an error object:

{
  "status": "error",
  "error": {
    "code": "RATE_LIMITED",
    "message": "Sender exceeded 10 requests per minute"
  }
}

Code reference

Code	HTTP	Meaning
`AUTH_FAILED`	401	Invalid or missing signature, unknown sender key, or missing Bearer token for an `authenticated` skill
`REPLAY_DETECTED`	401	Nonce has already been seen within the 5-minute replay window
`SKILL_NOT_FOUND`	404	Skill ID does not exist on this agent
`SCHEMA_INVALID`	400	Payload failed input schema validation (missing required field, wrong type, exceeded `maxLength`, etc.)
`INJECTION_DETECTED`	400	Payload flagged by the prompt injection scanner
`DELEGATION_EXCEEDED`	400	Delegation token’s `scope` does not include the called skill, or `maxDepth` has reached 0
`RATE_LIMITED`	429	Sender exceeded the per-sender request rate declared in the agent card
`TOKEN_BUDGET_EXCEEDED`	429	Sender exhausted their daily token budget; `Retry-After` header gives UTC midnight reset time
`AGENT_UNAVAILABLE`	500	Agent is overloaded, starting up, or the skill handler threw an unhandled exception

Code	Retry?
`AUTH_FAILED`	No — fix the request (verify key is active, token is valid)
`REPLAY_DETECTED`	Yes — generate a new nonce and timestamp
`SKILL_NOT_FOUND`	No — re-fetch the agent card; skill may have been removed
`SCHEMA_INVALID`	No — fix the payload
`INJECTION_DETECTED`	No — review the payload content
`DELEGATION_EXCEEDED`	No — request a new token with appropriate scope/depth
`RATE_LIMITED`	Yes — back off and retry after a moment
`TOKEN_BUDGET_EXCEEDED`	Yes — after the `Retry-After` header time
`AGENT_UNAVAILABLE`	Yes — exponential backoff