Error Handling

Cortex defines sentinel errors in the root cortex package. All errors are created with errors.New and can be checked with errors.Is.

Store errors01

Error	Description
`ErrNoStore`	No store was configured on the engine
`ErrStoreClosed`	The store has been closed
`ErrMigrationFailed`	Database migration failed

Error	Description
`ErrAgentNotFound`	Agent with the given ID does not exist
`ErrRunNotFound`	Run with the given ID does not exist
`ErrStepNotFound`	Step with the given ID does not exist
`ErrToolCallNotFound`	Tool call with the given ID does not exist
`ErrSkillNotFound`	Skill with the given ID does not exist
`ErrTraitNotFound`	Trait with the given ID does not exist
`ErrBehaviorNotFound`	Behavior with the given ID does not exist
`ErrPersonaNotFound`	Persona with the given ID does not exist
`ErrCheckpointNotFound`	Checkpoint with the given ID does not exist

Error	Description
`ErrAlreadyExists`	A resource with the same name already exists in this app

Error	Description
`ErrInvalidState`	Invalid state transition (e.g., completing an already-failed run)
`ErrRunCancelled`	The run was cancelled
`ErrRunAlreadyDone`	The run has already completed
`ErrBudgetExhausted`	Token or cost budget exhausted
`ErrMaxStepsReached`	Maximum reasoning steps reached
`ErrMaxTokensReached`	Maximum output tokens reached

Store implementations wrap these sentinel errors with additional context:

return fmt.Errorf("postgres: get agent %s: %w", agentID, cortex.ErrAgentNotFound)

Check errors using errors.Is:

agent, err := eng.GetAgent(ctx, agentID)
if errors.Is(err, cortex.ErrAgentNotFound) {
    // handle not found
}

The HTTP API maps sentinel errors to HTTP status codes:

Sentinel error	HTTP status
`ErrAgentNotFound`, `ErrRunNotFound`, etc.	`404 Not Found`
`ErrAlreadyExists`	`409 Conflict`
`ErrInvalidState`, `ErrRunCancelled`, etc.	`400 Bad Request`
`ErrNoStore`	`500 Internal Server Error`