build

name	build
description	Must use this skill when user triggers /ezfl:build or requests implementation / execution of tasks.md. Selects implementer subagent, which executes /opsx:apply in its own session — main agent is forbidden from directly writing implementation code.

build

Forbidden for the main agent to directly write implementation code in its own session. Forbidden to invoke /opsx:apply before Step 1 (Agent Selection via easy-flow:agent-selector) is complete. /opsx:apply must be executed by the implementer subagent, not the main agent; the subagent launch prompt must inject Constitution C constraints.

Must output on startup: [easy-flow] entering phase: build — using easy-flow:build skill.

Observed Hard Stops

This skill observes the following from hard-stops.md:

• H8 (status line output): Each Step entry outputs visible status lines like [easy-flow] entering build Step <N>: <action>
• H10 (agent-selector prerequisite): Step 1 must first call easy-flow:agent-selector; must not skip Agent Selection before launching the implementer subagent
• H13 (disable superpowers dispatch drivers): When Step 1 returns "inline", the main agent must run /opsx:apply inline, never falling back to superpowers:subagent-driven-development / :executing-plans

Flow

Execute step by step in order. Do not proceed to the next step until the current one is complete:

Step 0: Locate change_id

Read .harness/workflow.yaml: active_changes, filter for entries with phase=build:

• Single match: use its change_id
• Multiple matches: use ask_followup_question for user selection
• Zero matches: block, prompt "No active change found in design phase, please run /ezfl:design first"

Step 1: Agent Selection — implementer (mandatory, must not skip)

[Hard constraint] Before launching the implementer subagent, must first:

1. use_skill("easy-flow:agent-selector")
2. Input dispatch_point_id = "build.implementer"
3. Wait for return of one of three states (see selector SKILL.md "Output" section):
   • agent file path (string) — user selected a project-level agent from scan results
   • "default-subagent" — user chose D, main agent dispatches using host native subagent capability, no agent file specified
   • "inline" — user chose I or cancelled, main agent executes inline in its own session, no subagent dispatch

The return value is used for this build's implementer dispatch (see Step 2):

• Returns agent path → main agent dispatches via host native Task / AgentTool with that path as subagent_path
• Returns "default-subagent" → main agent dispatches using host native subagent capability, no agent file specified
• Returns "inline" → main agent executes /opsx:apply inline (injection point C is the main agent's responsibility)
• Host has no subagent capability → forced fallback to "inline": skip Step 2 subagent launch, main agent directly executes /opsx:apply

Skip self-check: If about to launch implementer / invoke /opsx:apply / dispatch implementation subagent / main agent directly writes code and Step 1 is not complete, immediately stop and output [easy-flow] BLOCK: Before launching implementer / invoking /opsx:apply in build phase, must first call easy-flow:agent-selector (dispatch_point_id=build.implementer). Agent Selection must not be skipped. then return to Step 1.

Step 2: Branch on selector three-state to execute /opsx:apply

Assemble launch prompt: read_file $PLUGIN_ROOT/skills/build/assets/implementer-prompt.md to get the prompt template text (three sections: task / Constitution injection point C / return contract). Replace the <change_id or omitted> placeholder in the template with the Step 0 location result; keep other <N.M> / <...> placeholders as-is (they are self-filled by the subagent at runtime).

Branch on Step 1 return value into three paths:

2.A — Returns agent file path (string)

Main agent dispatches subagent via host native Task / AgentTool:

• subagent_path = agent path returned from Step 1
• prompt = assembled launch prompt from above

Main agent must not intervene during subagent execution, only receives the final report.

2.B — Returns "default-subagent"

Main agent dispatches subagent via host native Task / AgentTool, without specifying subagent_path (handled by host default subagent):

• prompt = assembled launch prompt from above

Main agent must not intervene during subagent execution, only receives the final report.

2.C — Returns "inline" (main agent inline execution)

Main agent executes within its own session — no subagent dispatched:

1. First output the applicable Constitution principle list for this build (injection point C inline form);
2. Invoke /opsx:apply [<change_id>], wait for completion;
3. Within apply, before each task implementation, the main agent outputs [Constitution C] Task <N.M>: applicable principles = ... (injection point C mandatory clause, main agent bears responsibility).

Step 3: Exit Verification

After /opsx:apply returns (or subagent returns its report), verify:

1. All tasks in tasks.md have checkboxes checked (- [x]) — any - [ ] means incomplete
2. apply output includes Implementation Complete summary
3. Main agent did not directly write implementation code (violating Step 1 skip self-check means flow failure)

Hard block (any condition not met → forbidden to mark build.status=completed):

• Verification 1 fails (has - [ ]) → block, output [easy-flow] BLOCK: tasks.md has incomplete tasks, forbidden to mark build as complete. + list uncompleted task numbers, wait for user instruction (continue implementation / manually mark / abandon)
• Verification 2 fails (apply paused/errored) → block, present pause reason and options, wait for user instruction
• Verification 3 fails → block, flow considered failed
• All pass → commit worktree changes and mark complete:

cd "$WORKTREE_PATH"
git add -A && git commit -m "feat($change_id): implementation complete"

Write build.status: completed to state.yaml, output [easy-flow] build complete, next step recommendation: run /ezfl:audit

Constitution Injection Point C

• Implementer subagent (2.A / 2.B path) outputs [Constitution C] Task <N.M>: applicable principles = ... before each task execution
• Main agent injects this constraint as a mandatory clause into the subagent launch prompt during Step 2 assembly
• When taking 2.C (main agent inline), the main agent outputs the principle list for this build once in inline form before executing apply, and supplements [Constitution C] Task <N.M>: ... before each task