implement

name	implement
description	Execute one bounded RED to GREEN experiment from bead or caller intent; return derived subject identity and check facts. Triggers: "implement", "implement this bead", "run the experiment". Full plan-to-validation requests route to rpi.
practices	["tdd","refactoring","small-batch-flow"]
hexagonal_role	driving-adapter
consumes	[]
produces	["subject-manifest.v1"]
context_rel	[{"kind":"customer-of","with":"plan"}]
skill_api_version	1
user-invocable	true
metadata	{"graph_root":true,"tier":"execution","dependencies":[],"capabilities":["execute_one_experiment","collect_factual_evidence"],"effects":["modify_declared_subject","derive_subject_manifest"],"canonical_status":"canonical","disposition":"keep"}

Implement

Execute exactly one bounded experiment described by the resolved bead or caller intent. Implement owns subject edits and factual evidence. It does not create a second planning record or a model-authored candidate packet.

Workflow

1. Read the intent, acceptance, and scope from their existing source. A runtime may snapshot and hash that source automatically for drift detection.
2. Run the declared first acceptance check before changing behavior. RED-first applies only when acceptance is behavioral: preserve evidence that the check fails for the expected missing behavior. Relocations, doc merges, and pure refactors need no failing-check ritual — record an honest green pre-change baseline instead.
3. Make the smallest in-scope change that satisfies the active behavior.
4. Run the targeted acceptance checks and capture factual results.
5. Refactor only while those checks stay green. Refactoring does not change the acceptance test.
6. Have the runtime derive actual changed paths and subject-manifest.v1 from the before/after subject. Do not make the model transcribe those facts.
7. Return the manifest digest, author context ID, and exact check receipts in the response or runtime channel. Stop.

Specialists such as standards, domain, test, refactor, and security may provide advice. They are never hard dependencies and cannot add lifecycle authority.

Evidence proportionality

During edits, run the smallest deterministic checks that can falsify the active change. Reuse exact-input receipts when their subject and tool identity still match. Run an expensive full-suite check at the integration boundary, or earlier only when the intent explicitly makes it the first acceptance check. Repeatedly replaying the full suite after every focused edit adds latency, not proof.

Scope conflict rule

On discovering a live consumer of the change outside the declared write scope — a test asserting the old path, a generated twin, a gate reading the moved file — stop and report the exact file and line to the caller. Do not silently expand scope to absorb it. One repair revision of the intent is the maximum before escalating to the caller; the 2026-07-15 heal-skill fold took three intent revisions (lineage under .agents/ao/intents/sha256/26a4f2be...eb48) because hand-enumerated scope kept missing live consumers.

Before declaring GREEN, self-audit the diff for mocks, placeholders, TODO stubs, hardcoded fixture values, weakened assertions, regenerated goldens, widened tolerances, suppression directives, or specification edits standing in for real behavior. When the diff changes a test, gate, fixture, golden, or acceptance source, state why the original intent requires that change and confirm that green came from the implemented behavior rather than a weakened oracle. A check that passes against a substitute or weakened oracle is not evidence for the acceptance criterion; either finish the behavior or report it as not built.