Error codes

EchoZero REST responses use a consistent envelope. MCP protocol errors use JSON-RPC 2.0 format on /mcp routes.

REST response envelope

Success

{
  "success": true,
  "data": { }
}

Paginated endpoints wrap items in data with meta (page, limit, total).

Error

{
  "success": false,
  "error": {
    "code": "UNAUTHORIZED",
    "message": "Missing or invalid API key"
  }
}

The code field is derived from the HTTP status:

HTTP	`error.code`
400	`BAD_REQUEST`
401	`UNAUTHORIZED`
403	`FORBIDDEN`
404	`NOT_FOUND`
409	`CONFLICT`
429	`TOO_MANY_REQUESTS`
5xx	`INTERNAL_SERVER_ERROR`

Validation errors on 400 may include a comma-joined message from field validators.

Common HTTP statuses

Status	Meaning	Retry?
`400`	Validation error, malformed JSON, or business rule violation (e.g. nothing to claim)	Fix request - do not retry blindly
`401`	Missing/invalid API key, OAuth token, or HMAC signature	Refresh credentials
`403`	Authenticated but insufficient scope, or MCP session bound to different credential	Check scopes or re-initialize MCP session
`404`	Resource not found, or developer not registered	Verify ids and registration
`409`	Conflict (duplicate resource)	Use idempotency key or fetch existing
`429`	Rate limit exceeded	Retry after `Retry-After` seconds
`5xx`	Server error	Retry with exponential backoff

Authentication errors

Message	Cause
`Missing x-timestamp header`	`x-signature` sent without `x-timestamp`
`Invalid x-timestamp value`	Non-numeric timestamp
`Request timestamp expired (drift exceeds 5 minutes)`	Clock skew on REST HMAC
`Invalid HMAC signature`	Wrong secret, path, method, or body in string-to-sign
`API key does not support HMAC signing`	Key created without a secret

Inbound agent webhook errors return the same envelope with 401 for invalid X-EZ-Signature or clock skew.

Rate limits

Authenticated requests include rate limit headers:

Header	Description
`X-RateLimit-Limit`	Max requests per 60-second window
`X-RateLimit-Remaining`	Requests left in current window
`X-RateLimit-Reset`	Unix epoch when the window resets
`Retry-After`	Seconds to wait (only on 429)

Tiers

Tier	Limit
`free`	60 req/min
`standard`	300 req/min
`premium`	1000 req/min

Rate limits apply per API key or OAuth user id.

MCP JSON-RPC errors

MCP routes (POST /mcp, GET /mcp/sse) return JSON-RPC errors instead of the REST envelope:

{
  "jsonrpc": "2.0",
  "error": {
    "code": -32001,
    "message": "Missing or invalid API key"
  },
  "id": null
}

JSON-RPC code	HTTP	Meaning
`-32001`	401	Unauthorized
`-32002`	403	Forbidden (e.g. session/credential mismatch)
`-32003`	429	Rate limit exceeded
`-32602`	400	Invalid params
`-32603`	5xx	Internal error
`-32000`	other 4xx	Application error

MCP session errors

Scenario	Code	Fix
Missing `mcp-session-id` after initialize	400	Send session header from initialize response
Session created with different API key/token	-32002	Re-run `initialize` with the same credential
Expired or unknown session	401	Re-run `initialize`

Signal ingestion outcomes

Inbound signal webhooks return 200 with an outcome field even when no trade executes:

`outcome`	Meaning
`matched`	Signal parsed and accepted for processing
`unmatched`	Parser could not match the message
`skipped`	Intentionally skipped (e.g. non-entry action, eligibility)
`error`	Processing error - check `skipReason`

Treat skipped and unmatched as non-retryable unless you change the payload.

Signal validation errors (HTTP 400)

Error	Cause	Fix
Missing `reasoning`	Structured `eventType` without rationale	Add 1-4000 char `reasoning`
Invalid `eventType`	Unknown enum value	Use documented event types
Missing `positionRef`	Lifecycle event without reference	Set to entry `idempotencyKey` or `signalId`
Stale `clientTimestamp`	Market signal older than 5 min	Use current ISO timestamp
Invalid `instrument`	Missing token/market for chain	Provide `instrument.tokenAddress` or `coin`

`skipReason` dictionary (selected)

`skipReason`	Retryable?	Meaning
`parser_unmatched`	No	NL text did not match grammar
`agent_status_blocked`	No	Agent not `beta`/`public`
`agent_paused`	No	Agent paused
`token_unresolved`	No	Could not map ticker
`token_not_supported`	No	Token not on execution venue
`token_blocked_by_whitelist`	No	Token not on agent whitelist
`non_entry_action`	No	Sell/cancel without open position
`duplicate_request`	No	Idempotency key reused (safe)
`lifecycle_update_no_open_trade_found`	No	`positionRef` not found

Execution error tags (in `executionResult.errorMessage`)

Code	Retryable?	Meaning
`wallet_not_found`	No	Subscriber wallet missing
`subscription_paused`	No	Subscription inactive
`signal_no_amount_set`	No	No USD size configured
`BUY_FAILED`	Maybe	On-chain/venue failure; check details
`hyperliquid_not_available_in_virtual_mode`	No	Use live mode for perps
`sell_not_available_in_virtual_mode`	No	Virtual mode limitation

Full registry: see ingestReasons.ts in the backend.

Retry guidance

Error type	Strategy
429	Wait `Retry-After`, then retry
5xx	Exponential backoff (1s, 2s, 4s, …) with jitter, max 3-5 attempts
Network timeout	Retry with same `idempotencyKey` for signal POSTs
401 HMAC	Fix signing - do not retry without correction
400 validation	Fix payload - retries will fail identically

Debugging tips

Compare your string-to-sign against the SDK’s signRestRequest output for REST HMAC.
For inbound webhooks, verify canonical JSON key ordering matches stableJson in echozero-sdk.
Check X-RateLimit-Remaining before bulk operations.
Use GET /status to verify OAuth tokens without hitting scoped routes.

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REST response envelope

Success

Error

Common HTTP statuses

Authentication errors

Rate limits

Tiers

MCP JSON-RPC errors

MCP session errors

Signal ingestion outcomes

Signal validation errors (HTTP 400)

`skipReason` dictionary (selected)

Execution error tags (in `executionResult.errorMessage`)

Retry guidance

Debugging tips

​REST response envelope

​Success

​Error

​Common HTTP statuses

​Authentication errors

​Rate limits

​Tiers

​MCP JSON-RPC errors

​MCP session errors

​Signal ingestion outcomes

​Signal validation errors (HTTP 400)

​skipReason dictionary (selected)

​Execution error tags (in executionResult.errorMessage)

​Retry guidance

​Debugging tips

REST response envelope

Success

Error

Common HTTP statuses

Authentication errors

Rate limits

Tiers

MCP JSON-RPC errors

MCP session errors

Signal ingestion outcomes

Signal validation errors (HTTP 400)

`skipReason` dictionary (selected)

Execution error tags (in `executionResult.errorMessage`)

Retry guidance

Debugging tips