MARSHAIL Implement stage. Delegate when the user asks to "implement phase X", "work on packet Y", "code this packet", "execute the plan", "start the next implementation cycle", "do the work for the current target", "write the code + tests for this", "run a Dev-QA pass", "close this cycle". Also delegate after the Plan stage (plan approved) to drive each implementation cycle, and after a verifier failure or reviewer fixup loop to resume coding. The subagent picks the cycle target, confirms / deepens the plan, executes (code + tests + Dev-QA where possible), offers the human a chance to inspect and give feedback, and closes the cycle by updating plan status, changelog, and learning files.
Copies MARSHAIL durable assets — both built-in lifecycle assets under `.marshail/{skills,skills-fallback,agents,rules}/` and repo-specific extensions under `.marshail/extensions/{skills,agents,rules}/` — into the project's config-sync source tree (default `.agent-config/`, overridable via `sync.agent_config_dir`), so the next `agent-conf-sync` run fans them out to all tool layouts. Names are preserved as-is: built-ins keep their `marshail-` prefix, extensions keep their `mx-` prefix. Use when the user asks to "promote MARSHAIL skills/agents/rules", "promote MARSHAIL extensions", "copy from .marshail to .agent-config", "wire MARSHAIL assets into the sync source", or similar — and from `marshail-init` for first-time setup.
MARSHAIL Repo recon / analysis stage. Delegate when the user asks to "analyze the repo for this change", "do recon", "narrow the search surface", "find the likely files / services / contracts", "identify invariants and test seams", "produce repo-recon.md", "what touches X in this codebase?", "where does Y live?", "scope the code areas before planning". Also delegate when change-brief.md exists and the Analysis stage is in scope, or when a planner / implementer flags they don't know enough about an area. The subagent reads the brief and existing knowledge, walks likely paths, and returns a tight repo-recon.md plus a stale-knowledge list — keeping intermediate exploration out of the parent context.
MARSHAIL Architecture / design stage. Delegate when the user asks to "design the solution", "agree the implementation concept", "discuss the architecture", "propose components / modules / APIs / schemas", "produce architecture-notes.md", "draft an ADR for this", "what's the right shape for this?", "compare design tradeoffs", "high-level layout for this change". Also delegate when change-brief.md and repo-recon.md exist and the change is large enough that the solution shape isn't obvious yet. The subagent drives the design conversation, captures rationale, and (when significant) promotes durable decisions to ADRs.
Run a whole MARSHAIL change end-to-end. Delegate when the user asks to "run MARSHAIL on this", "do a full MARSHAIL change for X", "orchestrate this change end-to-end", "drive this through MARSHAIL stages", "manage stage transitions for me", "resume this MARSHAIL change", "pick up where the change left off", "I want one orchestrator instead of juggling stages", or any high-level "do the whole thing under MARSHAIL" intent. Also delegate when starting a new change in a MARSHAIL repo (with `.marshail/` initialized) and the user wants per-stage approval gates managed automatically. The subagent agrees scope, detects current stage from on-disk artifacts, dispatches per-stage agents, and surfaces approval gates.
MARSHAIL on-demand help. Delegate when the user asks "how does MARSHAIL work?", "what does the X stage do?", "which skill / agent should I use next?", "what stage am I in?", "explain the knowledge layer", "how do I write a delivery plan?", "what goes in repo-recon.md?", "how does the config sync fit in?", "what's the difference between marshail-init and marshail-load?", "what's the marshail acronym?", "MARSHAIL?", or any procedural / conceptual question about the MARSHAIL process, the knowledge layer, the available skills / agents, or how MARSHAIL applies to the current change. Also delegate when the caller is unsure which skill / agent to use, or when another skill / agent encounters a MARSHAIL-meta question that would pollute its context. The subagent reads marshail.md and the repo's .marshail/ tree, returns a concise answer, and (when asked) hands off — read-only.
MARSHAIL Intake / framing stage. Delegate when the user asks to "frame the change", "write the change brief", "produce change-brief.md", "structure the engineering framing for this change", "list the non-goals and acceptance criteria", "convert the spec into a brief". Also delegate when the Specification stage is finished (specification.md exists) and the Intake stage is in scope, or when the user has a clear prompt but wants a structured brief before analysis/planning. The subagent turns the spec or prompt into change-brief.md (problem, scope, non-goals, acceptance criteria, constraints, rollout expectations).
Reconcile MARSHAIL knowledge files diverged on two branches. Delegate when the user asks to "merge knowledge files from two branches", "resolve a conflict in .marshail/knowledge/", "reconcile knowledge changes between feature branch and trunk", "3-way merge knowledge frontmatter and bodies", "handle overlapping repo_paths between branches", "two branches independently added domain notes — merge them". Use at merge time when both sides changed `.marshail/knowledge/`, when there's a git conflict in a knowledge file, or when both branches added content in overlapping areas without textual conflict. The subagent (curator in mode `branch-merge`) performs the merge per the autonomy mode — applying it and returning a short summary in `auto`, or returning a summary diff plus any items needing human resolution in `review`.