Harness Planner

Harness planner

Selection procedure for the Planner persona. The prompt at agent/harness/planner-prompt.md is the contract; this is the method.

1. Establish state

Run bash agent/init.sh. It resolves the dependency closure and tells you what is genuinely unblocked, so you do not recompute it.

Read agent/harness/horizon.json. The previous run left a lookahead. Treat its head as the default choice and only depart from it with a reason you write down.

2. Build the candidate set

A candidate must satisfy all of:

• status is not completed
• every id in depends_on is completed
• it is not in the in-flight exclusion list appended to the prompt
• it advances at least one facet or outcome in agent/vision.md

If the set is empty, the correct output is a new feature you define fully, not the least-bad existing one.

3. Score

In order:

1. Vision alignment. Which facet, which outcome, and how directly. A task that advances a facet indirectly loses to one that advances it head-on.
2. Category balance. Compare the mix across the current slice and the last several PROGRESS.md entries against the weights in agent/categories.json. Correct the largest deviation.
3. Priority. The tiebreak, not the driver.

Two patterns worth naming:

• Lock after ship. When the previous run shipped behaviour, the strongest next task is usually the eval that locks it while the shape is fresh.
• Unblock the widest. When several tasks tie, prefer the one the most other features depend on.

4. Size

One task, one pull request, inside the caps in agent/harness-config.json. If it does not fit, the plan is to split it and the chosen task is the first slice. Say so in alternatives_considered.

5. Write constraints that can be broken

execution_constraints is what the Validator judges against, so each one must be falsifiable by looking at a diff.

Weak: "keep the change focused", "do not break anything". Strong: "only src/lib/** and src/eval/** may change", "no new dependencies", "npm run verify must pass", "do not modify the hybrid search weights".

Same for principles: quote real text from AGENTS.md, .agents/rules/, or agent/vision.md. The Executor restates them and the Validator checks compliance, so an invented principle corrupts both.

6. Persist

Write the plan JSON and its narrative companion to the paths in agent/harness/artifacts.json, then update agent/harness/horizon.json with the new slice and a rationale per step.

Write nothing else. No source, no tests, no feature_list.json.