opencode-intent-gate

A TypeSafe Jev powered plugin for OpenCode that makes the agent confirm intent before diving into underspecified requests.

Agents love to silently start digging. When a request is vague ("just fix it somehow"), they pick an interpretation and run with it — investigating, editing, sometimes wrecking things. opencode-intent-gate inserts a judgment step before the turn starts: if the request looks underspecified, it injects a system directive telling the agent to ask 1-3 clarifying questions first instead of calling tools.

How it works

user message
  → session hook "context" (right before model dispatch)
      → judge the latest user message with Jev (4 noul questions, 1 request)
          is_work_request / ambiguous / missing_user_info / scope_unclear
      → plain-code thresholds decide: gate or pass
  → if gated: push a directive into the system prompt
      "ask before acting; do not start tool calls this turn"

The decision is made from calibrated probabilities, not vibes: Jev returns noul scores and the thresholds are ordinary code constants you can tune. Verdicts are cached per message, so each user message costs one request of roughly 500 tokens (~0.5s, ~$0.00002).

Measured behavior (Japanese requests)

| message | verdict | |---|---| | いい感じに直しといて | gate (ambiguous 0.81 / scope 0.97) | | app/main.go のビルドエラーを直して | pass | | これってどういう意味？ | pass (not a work request) | | 予想ロジックを改善して。あとで見るから、いい感じに。 | gate | | tmp/... を読んで要約して | pass | | 掃除は今して | pass (specific follow-up) |

Requirements

• OpenCode V2 beta (tested on opencode2 0.0.0-beta-19271)
• A TypeSafe API key: sign in at https://console.typesafe.ai and issue one (a trial credit is included)

Beta note: this plugin judges from the context hook (which runs before every model dispatch) instead of the prompt hook, so it works across OpenCode V2 betas. Tested on beta-19271.

Compaction requests and other runtime-generated messages are never gated. The hook returns before judging when the agent is compaction, when the latest user message is a compaction prompt (You MUST summarize the conversation above... or Update the existing checkpoint...), when it is an id-less synthetic prompt about summarizing, or when it is a runtime notice (interruption/server-restart resume, max-steps, user-executed tool reports, plan-mode reminders, subagent reports). Skips are recorded in the log as event: "skip" with a reason.

Install

opencode plugin add opencode-intent-gate

Or run from a local checkout:

git clone https://github.com/hoshinodis/opencode-intent-gate ~/app/opencode-intent-gate
ln -s ~/app/opencode-intent-gate ~/.config/opencode/plugins/opencode-intent-gate

Provide the API key to the process that runs the OpenCode service:

export TYPESAFE_API_KEY=...

or drop the key into ~/.config/opencode/typesafe/api_key.

Options

Options can be passed where the plugin is registered; defaults shown below.

| option | default | meaning | |---|---|---| | enabled | true | also disabled with TYPESAFE_INTENT_GATE=off | | model | jev-latest | pin e.g. jev-1.13.0 for reproducibility | | isWorkThreshold | 0.5 | minimum is_work_request score to consider gating | | dimensionThreshold | 0.75 | any ambiguity dimension at or above this gates | | timeoutMs | 2500 | request timeout; on timeout the gate is skipped (fail-open) | | minChars | 2 | skip messages shorter than this | | maxChars | 4000 | clip the text sent to Jev to this many characters (head + tail), so attached-file expansions cannot blow past the request limit | | apiKeyEnv / apiKeyFile | TYPESAFE_API_KEY / ~/.config/opencode/typesafe/api_key | key lookup order | | logFile | ~/.config/opencode/intent-gate/decisions.jsonl | JSONL decision log |

Safety

• fail-open: API errors and timeouts never block the prompt; after 3 consecutive failures the gate pauses for 5 minutes
• acknowledgements (ok, はい, thanks, ...) and slash commands are skipped
• the gate is a system directive, not a hard block. Pair it with tool permissions if you want enforcement.

Development

npm install
npm run typecheck

License

MIT. Not affiliated with TypeSafe or OpenCode.

日本語

曖昧な依頼でコーディングエージェントが勝手に走り出すのを防ぐ、TypeSafe Jev 製の OpenCode プラグイン。モデル送信直前の context フックで最新のユーザーメッセージを4つの noul 質問（作業依頼か / 曖昧か / ユーザーしか知らない情報が必要か / スコープ不明か）で判定し、「確認すべき」と判定されたときだけ「ツールを使う前に質問しろ」という指示を system プロンプトに注入します。判定は確率スコアとコード側の閾値で決まり、失敗時は素通し（fail-open）。