AI agents

Tool contracts and error shapes

• A Tool Contract for Failure: Inputs, Outputs and Error Codes
• Error Envelopes Across Tool Types: HTTP, Database, APIs
• Schema Tests for Tools: Fixtures That Assert Every Error Code
• The Envelope's Version Field: Adding a Class Safely
• A First-Key Contract for an Internal API Between Two Teams
• A Reason Code Namespace Behind the Envelope Version
• A Subscriber Manifest: Which Services Depend on Which Fields
• Contract Tests Between an Agent and Its Tool Schema
• Contract Tests for Every Read Error: Timeout, Partial and Denied
• Contract Tests for the Error Classes a Memory Store Returns
• Extending the Error Shape to Timeouts, Partial Reads and Denials
• Logging a Caller That Sends an Unknown Envelope Version
• Parsing an Envelope for Fields Your Client Does Not Know
• Writing a Tool Contract: Inputs, Outputs and Failure Modes