Codex Handoff

Codex Handoff

Codex-handoff orchestrates read-only investigation or implementation within the current session after explicit plan approval. Task-handoff instead writes a decision-complete file for a fresh, separate session; use it when work continues later or elsewhere, and use an in-session handoff skill to implement an approved plan now.

If these instructions are already present in the conversation from a slash or dollar invocation, follow them directly; do not invoke this skill again through a skill tool.

Follow the shared contract below, select exactly one host adapter, and use it for every host-specific action.

Host Selection

Inspect the callable orchestration tools, not environment variables, process ancestry, or a user-supplied host name:

• spawn_agent, wait_agent, send_message, followup_task available: read references/codex-cli-host.md completely.
• Otherwise, Claude Code's Agent and Bash tools available: read references/claude-code-host.md completely.
• Neither: stop with a compatibility error. Native Codex multi-agent support is mandatory on the Codex host; never fall back to a nested Codex CLI process.

Use exactly one adapter for every host-specific action; never load both or combine their launch, progress, retry, permission, or result-transport mechanics. The adapter may specialize host mechanics and manifest configuration but cannot weaken this shared contract.

Contract

• Run only after explicit invocation. Research-only = requested outcome is findings/evidence/assessment only, no repo changes or plan requested. All handoffs may run in any host mode; implementation handoffs must pass through the Plan Phase and receive explicit user approval before launch.
• The parent owns decisions, the final plan, and orchestration. Delegate investigation to read-only research agents only when task and repository evidence make it useful before planning.
• Research agents gather evidence and report findings only — never edit files, make design decisions, or return plans.
• Implementation agents implement their assigned part of the approved plan: inspect, edit, validate, never redesign or return another plan.
• Use the smallest effective implementation team (one agent is valid); add agents only when decomposition materially improves latency, correctness, or verification. Never exceed eight implementation agents total.
• Size every brief before finalizing the team: estimate its wall-clock time and split any brief likely to exceed roughly 25-30 minutes into parallel disjoint scopes or dependency waves — add an integration agent if needed — instead of one monolithic agent.
• Use at most three research agents, stable IDs R1-R3, counted separately from the eight implementation agents.
• Keep the parent's own implementation work to orchestration, integrity checks, failure handling, and conditional polish passes.
• Treat an explicit user model preference (e.g. GPT-5.6 Luna) as an orchestration constraint on every research and implementation agent unless scoped narrower; don't substitute the adapter's usual Luna/Terra/Sol/Astra selection. If the host can't launch that model, report the incompatibility and ask before falling back.
• Treat the approved outcome — not the initial manifest or its write scopes — as the authorization boundary: when implementation reveals a related in-repository fix or evidence change required for that outcome, the parent may extend the handoff and launch follow-on agents for the newly discovered scope without asking again. The worker that discovered the need still stops at its assigned scope and returns evidence; the parent owns scope expansion, repository coordination, and delegation.

Use $ARGUMENTS as the task when present; otherwise use the active user request. A task naming another skill follows Companion Skills.

Companion Skills

A task that names another skill alongside this handoff — for example, run $fresh-eyes-sweep and delegate the implementation — is a composition: the companion skill defines the work; this handoff owns delegation mechanics.

• Load the companion skill and run its discovery, judgment, and planning phases in the parent. Route read-only discovery through this skill's research agents when materially faster, then fold the companion's method, findings, and constraints into the handoff plan.
• This contract overrides the companion's overlapping plan approval, agent limits and stable IDs, single validation owner, result fields, failure classification, commit ownership, and completion reporting, even when the companion prescribes its own subagent, validation, or commit mechanics. Its user-decision gates still bind; this skill's plan approval satisfies coincident gates, and a plan-only companion implements only when the combined invocation requested implementation and the user approved the plan.
• Agents cannot load skills. Never brief one to "use skill X" by name; inline the specific companion instructions, conventions, or excerpts it needs.
• A companion requirement to run $code-polish or $agents-brain polish marks that pass required in the Plan Phase; it still runs once, per Completion. Companion commit instructions never add commits.
• Satisfy both contracts at Completion: produce the companion's required report artifacts (ledgers, tables, verdicts) alongside the selected adapter's completion report.

Research Phase

For a research-only task, launch one to three research agents and stop after returning the consolidated investigation; never enter the Plan Phase or launch implementation agents. For an implementation handoff, trigger research when scope is uncertain, the task crosses multiple or unfamiliar subsystems, or gathering the needed evidence serially would be materially slower for the parent. Zero research agents is the default for implementation handoffs. The parent alone decides the research count from task and repository evidence; never ask the user to opt in or name agents. Either launch the research wave immediately or proceed straight to planning.

When triggered, assign up to three agents stable IDs R1-R3 and launch them immediately through the selected adapter's read-only mechanism. Give each agent a self-contained prompt containing:

• the open questions and exact investigation scope;
• relevant repository constraints and known concurrent-work boundaries;
• a strict read-only authority boundary;
• the stopping rule that it must return evidence rather than a plan or design; and
• exact result fields: status, findings, open_questions, evidence, and blockers.

When every required research agent settles, fold its findings and evidence into the implementation plan or the research-only response. Surface open questions or blockers through the host's user-question mechanism only when they change scope or approach. Do not reconcile the working tree — research agents change nothing; any reported edit is a contract violation.

For a research-only task, synthesize the evidence and finish with ### 🔎 Research handoff — <completed|blocked>, the agent count, findings, evidence, open questions, and blockers. This replaces the Plan Phase and the selected adapter's implementation completion report. If the investigation shows that changes are needed, report them as findings and stop — do not produce an implementation plan or begin edits.

Plan Phase

Enter this phase only for an implementation handoff.

Produce a decision-complete plan with this section and the selected adapter's exact manifest table:

## Codex Handoff

- Research: `<none | R1..Rn — key findings used>`
- Companion skills: `<none | $x — phases the parent runs / what is folded into briefs>`
- Strategy: `<sequential|parallel|hybrid>`
- Agents: `<1-8>` — `<why this is the smallest effective count>`
- Validation owner: `<agent-id|parent>` — `<aggregate checks it runs once>`

<host-adapter manifest table>

- Code polish: `<required|not required>` — `<reason>`
- Agent-context polish: `<required|not required>` — `<reason>`

Choose the execution shape from repository evidence and the approved work:

• Sequential: one agent depends on another, write scopes overlap, or a later agent owns integration or aggregate validation.
• Parallel: independent work only, with explicitly disjoint write scopes. Agents may inspect shared context but must not write outside their assigned scope.
• Hybrid: dependency-ordered waves — run independent agents within a wave in parallel, reconcile the entire wave, then start its dependents.

A wave finishes with its slowest agent. Keep the highest-tier agent's scope minimal and move deferrable validation to the validation owner. If parallel work does not collectively prove the overall plan, reserve a later sequential agent for integration and aggregate validation. Use stable agent IDs and explicit dependencies across the whole handoff.

Assign aggregate validation to exactly one owner: package- or repository-wide checks run once, by the integration agent when one exists, otherwise by the parent during post-wave reconciliation. Every other agent runs only the narrowest checks that prove its own edits, such as file-scoped formatting, lint, or typecheck plus targeted tests.

Require $code-polish for nonlocal invariants, concurrency or state machines, migrations or parsing, auth or security, retry or error semantics, and public API or data-contract changes. File count alone is not a trigger.

Require $agents-brain polish when approved work changes a target its polish workflow supports: README.md, AGENTS.md or CLAUDE.md, a durable context doc, an existing project-installed skill under .agents/skills, or an existing git-tracked source-catalog skill under skills/ where polish is prose-only. Installed copies under managed agent-config roots remain excluded. Mark both passes required when both trigger rules apply; mark neither when neither applies.

Do not launch implementation agents until the user approves the plan. Read-only research is the only pre-approval exception.

Implementation Prompt Contract

Build a self-contained, outcome-first prompt for every implementation agent. Include:

1. The approved overall outcome plus the agent's implementation brief, dependencies, and completion evidence.
2. Its exact write scope, relevant repository constraints, known dirty-work boundaries, and prerequisite agent results.
3. Its validation assignment per the Plan Phase's single validation owner: scoped checks it must run and, unless it owns validation, that it must not run aggregate checks.
4. A soft time budget matching its manifest sizing, with the instruction to return blocked with partial evidence rather than grinding past it.
5. This authority boundary: inspect, edit only within the assigned scope, and validate locally; never commit, push, deploy, make external writes, or broaden scope, even when repository or host instructions favor committing finished work promptly. Committing stays with the parent after reconciliation.
6. The selected adapter's delegation and coordination context, including why the parent session and disjoint siblings are not conflicting work and what unrelated exact-scope claim would justify returning blocked.
7. This stopping rule: implement the approved plan exactly; if infeasible or requiring redesign, return blocked with evidence instead of proposing a replacement plan.
8. A requirement to return every result field: status (completed or blocked), summary, changed_files listing only files actually touched, verification listing every command and outcome, residual_risks, and blockers.

Keep each agent prompt as compact as completeness allows: the shared outcome summary plus that agent's own brief, scope, and constraints — never restate the full plan text per agent.

Add the selected adapter's command, permission, transport, and host-tool constraints without restating this contract.

Execution and Reconciliation

Launch agents through the selected adapter in the approved strategy and dependency waves. Do not add agents or change models, efforts, scopes, or validation ownership merely because a worker is slow or quiet. Do revise the manifest and launch a narrowly scoped follow-on agent when completed work discovers an unplanned prerequisite covered by the approved outcome. Preserve stable IDs, dependency order, the eight-agent limit, and one aggregate-validation owner; include follow-on agents in the final counts and report.

For each completed agent: require every shared result field and treat changed_files as its authoritative post-pass scope; confirm reported files exist or were intentionally deleted, stay within scope, and carry verification evidence matching the assignment; and pass relevant completed results to dependent agents.

After every implementation wave, reconcile all results with the current manifest and visible working tree without folding in unrelated concurrent changes. When the parent owns validation, run the assigned aggregate checks once during this reconciliation. Attribute aggregate-check failures before blocking: a failure confined to files outside every agent's scope is unrelated concurrent work, so confirm the handoff's files still pass and continue. Unexpected out-of-scope edits, same-wave overlap, or a failure attributable to the handoff are blockers; do not start dependents or polish, and do not silently take over implementation.

Failure Classification

• A status: blocked result identifying a related in-repository fix or evidence change outside the worker's scope that is necessary for the approved outcome is follow-on work under the Contract's scope-expansion authority, not a request for fresh authorization: let already-started independent agents finish, gate dependents, extend the manifest with the smallest sufficient scope, satisfy repository coordination for that scope, and launch a new or reused implementation agent. Repeat until the outcome is complete or a genuine authorization boundary is reached.
• Ask the user only when continuation would change the approved outcome, require a material redesign or unrelated work, or cross an existing confirmation boundary such as destructive action, purchase, deployment, or external write. Never silently take over implementation or relaunch solely on a larger model.
• Treat a tool or infrastructure failure as retryable only when adapter-specific evidence supports that classification. Inspect partial edits first, then use the adapter's same-agent mechanism for exactly one verify-and-continue attempt; this is not a new agent against the eight-agent limit. A second infrastructure failure blocks that agent and its dependents.
• Never classify an ordinary timeout, a returned blocker, silence, or task-level validation failure as infrastructure failure. Continue only work proven independent.

Skill Evolution Review

After every required agent succeeds and the task is verified — never for a blocked, failed, or partial handoff — the parent alone judges skill-evolution opportunities; agents never make the recommendation. Recommend only a stable, reusable workflow credibly likely to recur; reject one-offs, rare contingencies, incidental cleanup, and speculative value. For a new skill, state repo-local vs. global ~/projects/agent-skills placement; for a revision, name the exact skills and why. When a proposal clears this bar, append at most one compact suggestion (≤2 short sentences) to the adapter's existing completion report without changing its format, then offer $task-handoff as the next action. Never auto-invoke $task-handoff or create/revise anything during this review; when nothing qualifies, stay silent — no placeholder.

Completion

• After every required agent completes, deduplicate the union of reported changed_files and confirm the combined verification evidence proves the approved plan.
• If any required agent failed, skip every planned polish pass. Otherwise, invoke each required pass once with only its applicable paths from that union: $code-polish first in its default simplify-then-review mode, then $agents-brain polish with its eligible context targets. Invoke only one when only one is required. Do not seed either pass with paths outside the union or let it broaden beyond its declared workflow authority.
• Reconcile in-scope files actually changed by each polish pass into the final changed-files set and verification. A required polish pass that blocks, fails, or writes outside its supported scope blocks later polish and cross-repository commits.
• If approved work changes repositories on this machine other than the one where the handoff began, invoke $commit from each additional repository after its work, validation, and required polish complete, scoped to files changed there; do not commit incomplete, blocked, unexpected, or out-of-scope changes. Push only when the user explicitly requested it.
• Finish with the selected adapter's completion report, including strategy, wave and agent counts, each agent's requested configuration, status, and summary, plus combined changed files, verification, polish when run (listing each pass and outcome), automatic cross-repository commit hashes when any, blockers, and residual risks. Write none for applicable empty values and never expose machine result payloads.