build

Sprint 3 composable skill. Wraps the Builder phase. Builder is the only fan-out-incompatible phase — single worktree, single set of mutations.

When to invoke

• After tdd has produced RED tests
• Cycle is in tdd or discover phase per cycle-state

When NOT to invoke

• RED tests don't exist (TDD must run first)
• Cycle goal is research-only or planning-only

Workflow

Step	Action	Exit criteria
1	Read TDD contract from team-context.md	Contract loaded
2	Implement minimum code to turn RED → GREEN	Tests pass locally
3	Run regression suite (legacy/scripts/utility/run-all-regression-tests.sh)	No new regressions
4	Write <workspace>/build-report.md	Report present + fresh + token-bound

Single-writer invariant

Builder runs in a dedicated worktree. Concurrent builders are STRUCTURALLY blocked because:

• The trust kernel binds the cycle via SHA256 of git diff HEAD
• Two concurrent writers would invalidate each other's tree-state SHA
• phase-gate-precondition.sh allows only one active_agent per cycle

This is why Builder cannot fan-out even though Scout and Auditor can.

Phase facts

Fact	Value
Phase	build (build archetype, mandatory)
Persona	agents/evolve-builder.md
Profile	.evolve/profiles/builder.json — CLI codex-tmux, tier balanced, single-writer
Inputs	scout-report.md · triage-report.md
Artifact	build-report.md (cycle workspace)

Output contract

build-report.md must declare:

• ## Changes (also accepted: ## Files Changed, ## Files Modified)

Composition

Invoked by:

• /evo:build
• loop macro after /evo:tdd

Reference

• agents/evolve-builder.md
• .evolve/profiles/builder.json
• skills/loop/phase3-build.md (legacy detailed workflow)