Tendril – a self-extending agent that builds and registers its own tools
Summary
Tendril is a self-extending agentic sandbox that demonstrates the Agent Capability pattern: the model discovers, builds, and reuses tools autonomously across sessions. It maintains a capability registry and, if a requested action lacks a tool, writes and registers a new one, then executes it, making future invocations cheaper and smarter. The system uses a Strands SDK-based agent, a three-tool bootstrap loop, a sandboxed Deno process, and ACP-based communication over NDJSON to orchestrate think/act/observe phases.