Heddle
An open-source TypeScript agent runtime and SDK for durable conversations, tool and MCP execution, approvals and traceable activity, letting a product keep its own architecture while adopting only the layers it needs.
Heddle is a TypeScript SDK and runtime for building agentic features into a product without handing over control of identity, data relationships, API policy, deployment, transport or UI. A product can start with a plain conversation and progressively adopt further Heddle layers: a hosted run layer that adds addressable runs, replay and cancellation inside infrastructure the product already operates, and a separately deployed Execution Host reachable from any backend language through an OpenAPI or JSON Schema contract.
A CLI and browser control plane, built on the same runtime, let a developer try Heddle's local coding agent and terminal UI before embedding the SDK into their own backend. Package names were renamed during a stabilization pass, and the older coordinates remain installable only for existing consumers.