opencode-delegate — Claude Code skill: what it does, how to install

---
name: opencode-delegate
description: >-
  Delegate a coding task to the OpenCode CLI as a background implementer, then review its diff and
  land it yourself. Use this whenever the user wants to hand implementation work to OpenCode — phrasings
  like "have OpenCode do X", "delegate this to OpenCode", "run it through OpenCode", or "use OpenCode to
  implement/fix/refactor" — or wants to run a queue of coding tasks through OpenCode while staying the
  reviewer. Prefer it when the user will review the diff and commit it themselves. DO NOT USE for tasks
  small enough to do inline, or when the user wants the code written directly without delegating.
license: MIT
compatibility: Requires the `opencode` CLI installed and authenticated, Node 18+, and git. The orchestrating agent must be able to run shell commands and read files. Shell examples assume bash/zsh (macOS/Linux, or Git Bash/WSL on Windows).
metadata:
  version: 0.5.0
---

# OpenCode Delegate

You are the **orchestrator**. This skill lets you hand a bounded coding task to a separate
**implementer** — the OpenCode CLI — then review what it produced and land it yourself. You write
the brief and own the judgment; OpenCode does the typing in its own session; you verify and commit.

Nothing here is specific to one orchestrating agent. The loop needs only the ability to run a shell
command and read a file, so any agent with those two capabilities — Claude Code, OpenCode driving a
sibling session, or a comparable one — can drive it. (It is designed for and run on Claude Code; treat
other orchestrators as designed-for, not yet proven.)

## When NOT to use this

- The task is small enough to just do inline — delegation overhead is not worth it.
- The `opencode` CLI is not installed or not authenticated (run `opencode auth login`).
- You want to write the code yourself, or you only need a review (use the `plan` agent via `--read-only`).

## Prerequisites (check once)

1. `opencode --version` succeeds. If not, install (`npm i -g opencode-ai`, or the native installer from
   opencode.ai) and `opencode auth login`.
2. **Confirm which `opencode` is on PATH.** `command -v opencode` shows the active binary and
   `opencode --version` its version. The relay records the version it ran into `result.json`, so a stale
   binary is visible after the fact.
3. A model provider is authenticated — `opencode auth list` shows at least one credential.
4. You are in (or will point `--cd` at) the target git repository.

## Choose the implementer model

OpenCode has **no safe default** — a bare `opencode run` errors — so a fresh run needs a model via
`--model` or a fleet `--lane` that sets one (a resumed run inherits its session's model). Naming the
model is the one decision a single-model backend like codex-delegate never had, and it has two owners:

- **The human owns which models are allowed.** `opencode models` lists hundreds of entries, most billed
  per token (OpenRouter and the like); only the human knows which are their flat-rate subscriptions, and
  the CLI can't tell them apart. So the usable set is theirs — ideally stated once in the repo's
  `AGENTS.md` or their `CLAUDE.md` (e.g. "delegate mechanical work to `opencode-go/…`, hard logic to
  `…`").
- **You, the orchestrator, pick per task — from that set.** Match the model to the brief: a cheap, fast
  model for a mechanical sweep (rename, migration, removal); a strong one for a subtle bug or a
  money/security path.
- **If no usable set is stated, ask — don't guess.** Guessing from the catalog risks a metered model and
  a surprise bill. Name the constraint to the human and let them choose.

More depth: [references/writing-the-brief.md](references/writing-the-brief.md).

## The loop

Run these five steps per task. Steps 1, 4, and 5 are your judgment; 2 and 3 are mechanical.

### 1. Write the brief

OpenCode sees **only** the text you send plus what it can read from the working tree — no chat history,
no shared context. Everything the task needs goes in the brief: the goal, the current state, what to
change, what to leave untouched, the project's **actual** gate commands (discover them from the repo's
AGENTS.md/CLAUDE.md/Makefile — do not assume), and a report contract. Tell OpenCode it will **not**
commit (you will). Keep one task per brief. Full guidance and a template:
[references/writing-the-brief.md](references/writing-the-brief.md).

### 2. Dispatch

For **Codex orchestration of background work**, install and configure the separate
**codex-background** support utility first. If its MCP tools or registry are missing, stop and
report the setup requirement; do not silently fall back to model-driven polling. Then invoke its
registered `delegate_run` MCP tool once in place of the shell example below.
Follow that skill for structured common arguments, unchanged provider flags and reattachment by
runId. Keep the request pending until completion, then continue this skill's review and landing
steps. Other orchestrators keep the shell workflow below.

Send the brief to OpenCode with the bundled helper. It wraps `opencode run`, captures the run, and
writes a structured `result.json` — so your only job is "run a command, read a file." (`<skill-dir>`
below is this skill's installed directory — the folder containing this `SKILL.md`. Claude Code prints
it as "Base directory for this skill" when the skill loads; on other orchestrators use that same
directory — if unsure where it landed, run `find ~ -name relay.mjs -path '*opencode-delegate*'` and
substitute the directory above it.)

```bash
node "<skill-dir>/scripts/relay.mjs" --brief brief.txt --model <provider/model> --cd /path/to/repo
# --model (or a --lane that sets model) is required on a fresh run
# fleet lane from delegate-setup:           add --lane <name>  (dials apply; flags still win)
# read-only (review/diagnosis, no edits):   add --read-only   (uses the plan agent)
# continue the previous OpenCode session:   add --resume-last  (delta brief only; keeps the model)
# hard time limit (watchdog):               add --timeout 2h  (default: off; implementation runs routinely need 1-2h)
# see all options:                          node .../relay.mjs --help
```

The helper defaults to the write-capable `build` agent and writes its artifacts to a temp dir, so the
repo under review stays clean. It **never commits** — see step 5. Mechanics, flags, and the
`result.json` shape: [references/dispatch-and-poll.md](references/dispatch-and-poll.md).

### 3. Wait for completion

Codex using codex-background keeps the original MCP request pending: no model-driven sleep,
status or log polling. Use `delegate_wait` only to reattach after an interrupted request.

The helper blocks until OpenCode finishes, so back it with whatever your orchestrator offers and resume
when it returns:

- **Claude Code:** run the Bash call with `run_in_background: true`; you are notified on completion.
- **Plain shell / other agents:** run it in the foreground for short tasks, or background it and poll
  the result file — `… &` in bash/zsh (including Git Bash/WSL), or your shell's equivalent (`Start-Job`
  in PowerShell, `start /b` in cmd). The run is done when `result.json` exists with a `status`. (A
  pre-run usage error — bad args or an empty brief — instead exits with code 2 and writes no result
  file, so check the exit code too. A missing `opencode` binary exits 127 but *does* write a
  `result.json` with status `opencode_unavailable`.)

Do not trust progress trackers over reality: a run is finished when `result.json` is written and the
process has exited. Read the working tree, not a status line. The implementer's full report is
the `finalMessage` field in `result.json` (also printed in full on stdout between the report markers).

### 4. Review — do not trust the self-report

OpenCode's `result.json` includes its own final message and any gate claims. **Re-verify, don't accept:**

- **Re-run the project's gates yourself** (the test/lint/build commands from step 1). Never take
  "gates passed" on faith.
- **Read the diff** against the brief: did OpenCode do what was asked, nothing more (scope creep) and
  nothing less? `touchedFiles` in the result is your starting point.
- **Run the relevant guard skills** on the diff if you have them installed (clean-code-guard,
  test-guard, etc. from `guard-skills`) — this skill produces the work; those skills judge it.
- For schema/migration changes, round-trip them; for removals, grep for dangling references.

Full checklist: [references/review-and-land.md](references/review-and-land.md).

### 5. Land it

The implementer edits the working tree; **the orchestrator commits.** Committing should be the act of
the party that verified the work. Only after the gates pass and the diff holds:

- Commit the verified work yourself, with a clear message.
- If it needs changes, send a delta brief with `--resume-last` (don't restate the whole task) and
  review again.

## Autonomy model

OpenCode's autonomy is governed by the **agent**, not a sandbox enum:

- **`build`** (the relay default) — write-capable; edits files in the working dir headlessly. The
  equivalent of "let it implement."
- **`plan`** (via `--read-only`) — read-only; reviews and diagnoses without touching the tree. The
  equivalent of "let it look but not edit."

Permissions **auto-approve by default**: the relay passes `--auto` so a headless run never blocks on a
prompt no one can answer. That is the point of unattended delegation — the orchestrator's diff review
and the implementer sweep (step 4) are the safety net, not a per-action prompt. Pass `--no-auto` to
honor the agent's own permission config instead (allow/ask/deny per action); pair it with an agent whose
in-workspace permissions are set to *allow*, or a headless run can hang waiting on an `ask`.
**Read-only (`plan`) runs never get `--auto`** — auto-approving would let the plan agent's ask-gated
edit/bash permissions through and defeat "read-only," so a review can't be tricked into touching the tree.

## Authorization model

Delegation is something the human opts into. Once they have ("run this queue", "proceed"), committing
verified, gate-passing work is the agreed contract — that is the whole point. Two limits on that
mandate: **surface, don't absorb** (report OpenCode's design decisions, defensible-but-unasked turns,
and non-blocking nitpicks rather than silently keeping them) and **stop for scope changes** (if correct
completion needs going beyond the brief, ask — don't expand the mandate yourself). The full treatment
is in [references/review-and-land.md](references/review-and-land.md).

## References

- [references/writing-the-brief.md](references/writing-the-brief.md) — how to write a brief OpenCode can
  execute blind: structure, XML blocks, the report contract, embedding the real gate commands.
- [references/dispatch-and-poll.md](references/dispatch-and-poll.md) — `relay.mjs` flags, the
  `result.json` contract, backgrounding per orchestrator, and recovery when a run misbehaves.
- [references/review-and-land.md](references/review-and-land.md) — the review checklist, the commit
  boundary, and the rework cycle via `--resume-last`.
- [references/multi-task-queues.md](references/multi-task-queues.md) — running a sequential queue:
  carrying constraints forward, progress tracking, and the end-of-run coherence check.