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Every Harness Will Become A Claw — Sam Bhagwat, Mastra
Takeaway
The next evolution of agent harnesses combines durable execution with proactive triggers and learning from experience.
Summary
- Bhagwat describes a progression from LLMs to tool-using agents, durable harnesses, always-on cloud harnesses, and proactive claws.
- Harness capabilities include persistent threads, planning, parallel subagents, background tasks, compaction, and user steering.
- Cloud harnesses add shared messaging channels, remote access, sandbox parallelism, and pull-request delivery.
- The proposed claw transition adds initiative and learning through external event feeds, periodic wakeups, persistent memory, and automatically generated skills.
agent-harnessmastraproactive-agents
Original description
Most harness discussion is a reprise of Context Engineering from last summer. But it is not 2025 anymore: we live in a Claude Code world, and the best way to think about a harness is Context Engineering + Coding Agents = Harness. Harnesses are a powerful developer experience because of planning mode, parallel subagents, skills, background tasks, and more. But they do not stop there. Teams are putting harnesses in a box, making them listen to external events, giving them channels to ping users, and a heartbeat. They are becoming Claws. The argument is that harnesses want to become claws: more present in collaboration workflows and available while users are away. Sam proposes Steinberger's law, a spinoff of Zawinski's law: every harness will expand until it becomes a Claw. Speaker: Sam Bhagwat — Founder and CEO, Mastra Sam is the co-founder and CEO of Mastra, the TypeScript agent framework; author of Principles of Building AI Agents; and previously a Gatsby co-founder. X/Twitter: https://x.com/calcsam LinkedIn: / sambhagwat