Capture the trajectory.
Leave the secrets behind.
Harnest is how Thought Needle records what agents do. It turns each run into a structured trajectory — and removes personal and sensitive data on the client, before a single byte leaves the machine.
Talk to us about HarnestRedaction happens
where the work happens.
Most tools send data first and promise to protect it later. Harnest inverts that: sensitive data is removed on-device, so it's never in transit and never at rest on our side.
- 01
Observe locally
Harnest captures the agent's steps — prompts, actions, tool calls, and results — in the environment where the run happens.
- 02
Strip PII on-device
Names, emails, keys, tokens, and file paths are detected and masked before transmission — deterministically, so you can audit exactly what was removed.
- 03
Transmit structure only
What leaves the machine is the cleaned trajectory: the shape of the work, not the sensitive contents of it.
- 04
Put to work
Cleaned trajectories become RL environments, analytics, and signal — with you retaining ownership of what you captured.
Structure you can
actually learn from.
The observation an agent had at each step — the context it was reacting to.
What it chose to do — the tool call, the edit, the command — and why the step existed.
What came back, whether it worked, and how the agent recovered when it didn't.
Captured as a sequence, a trajectory shows not just outcomes but the path — the part benchmarks never see.
Want to capture
your agents' trajectories?
Harnest is rolling out with early partners. Tell us about your setup and we'll take it from there.
hello@thoughtneedle.com