Trajectory Search

Sat, 08 Aug 2026 17:26:00 +0100

An agent can make every local decision look reasonable and still lose the task.

A coding agent sees that test_checkout_redirect is failing, concludes there is an implementation bug in checkout.py, and then behaves impeccably for twenty steps: it reads the file, edits it, runs the tests, repairs the new failures its edit introduced, rewrites the patch, and runs the tests again. Every one of those steps is defensible given the step before it.

Agents From First Principles 08: AI Agent Picks the First Solution? Add Search Instead of One-Shot Generation

Sat, 08 Aug 2026 17:26:00 +0100

An AI agent often fails for a surprisingly ordinary reason:

it commits too early.

It finds one plausible next action, follows it, and then spends the rest of the run trying to make that first choice work.

That can look intelligent because the agent keeps reasoning, calling tools, revising plans, and explaining itself.

But underneath, the trajectory may be almost completely determined by an early mistake.

A coding agent chooses the wrong implementation strategy and spends twenty tool calls repairing it.

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Trajectory Search

Agents From First Principles 08: AI Agent Picks the First Solution? Add Search Instead of One-Shot Generation