# Use V4 Flash Worker

> Use only for an existing Codex 0.148.x-or-older DeepSeek-backed v4_flash_worker installation; contains the legacy plaintext-Hook handoff, recovery, and data-boundary contract. On Codex 0.149.0 or later, direct cross-provider work to MixAgents Broker instead.

- Skill: `utopia-v/use-v4-flash-worker` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add utopia-v/use-v4-flash-worker`
- Raw SKILL.md: https://api.skillmd.com/api/skills/utopia-v/use-v4-flash-worker/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: Utopia-V (https://skillmd.com/u/utopia-v)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/utopia-v/use-v4-flash-worker

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# Use V4 Flash Worker (legacy)

## Check compatibility first

Read the active Codex version before staging an assignment or spawning a child.
If it is `0.149.0` or later, stop without calling a provider and direct the user
to [`mixagents-broker`](https://www.npmjs.com/package/mixagents-broker) and its
[installation guide](https://github.com/Utopia-V/mixagents/tree/main/packages/broker).
If the version cannot be established, treat this native route as unqualified
and do not dispatch it.

Do not migrate the task to Broker automatically. The user must install and
configure Broker before using its provider routes.

## Select legacy work

- Select Flash only when the user requests it or its provider-declared 1M
  context changes whether a bounded, preferably read-only reading task is
  feasible. It is not the routine factual scout.
- Keep coupled reasoning, consequential decisions, verification, and final
  integration in the parent. Use a multimodal worker for images.
- The assignment crosses the configured DeepSeek data boundary. Sensitive
  material requires user authorization; credentials remain in the provider
  environment. Delegation never changes the parent's model or provider.

## Deliver one self-contained job

1. Build one complete assignment containing child identity, objective, scope,
   exclusions, available permissions, evidence or output contract, and stopping
   condition. Keep it in parent-owned execution state; do not publish it as
   user-visible commentary merely for transport.
2. Pipe the assignment through stdin to the installed handoff script in
   `stage` mode. Use the standard installed path below. If it is absent, inspect
   the effective `SubagentStart` Hook matching `^v4_flash_worker$` and use the
   same reviewed script path with its mode changed from `hook` to `stage`:
   - Windows: `powershell.exe -NoProfile -NonInteractive -ExecutionPolicy Bypass -File "<codex-home>\hooks\codex-deepseek-subagent\plaintext-handoff.ps1" -Mode stage`
   - macOS/Linux: `python3 "<codex-home>/hooks/codex-deepseek-subagent/plaintext_handoff.py" --mode stage`
3. Require a successful stage result naming `v4_flash_worker`. Treat a lock
   contender, an active pending or claimed item, quarantined state, or any other
   non-success result as a transport failure. Never spawn after a failed stage.
   Retry the complete stage only after the occupied state is explicitly clear,
   and spawn only after that new stage succeeds.
4. Immediately create the child through Codex's native `spawn_agent` with the
   exact agent type `v4_flash_worker`, a unique task name, and
   `fork_turns="none"`. Do not replace this with a provider CLI, direct API call,
   or inherited root history. Keep all essential instructions in the staged
   assignment; let the spawn message only identify the trusted one-shot Hook.
5. Receive the child through Codex's native wait/callback path. Use one
   task-sized idle wait or callback; do not short-poll, duplicate the child work,
   or invent another return transport while it runs.
6. Verify the returned contribution in proportion to the parent claim, then
   integrate it in the parent context.

## Respect dispatch and delivery semantics

- Treat delivery as one-shot and at-most-once. Never assume a claimed assignment
  can be replayed or delivered to a replacement child.
- After a worker has received its assignment, it no longer holds the dispatch
  lock; you may stage and spawn the next job before that worker returns, and
  already-running workers continue concurrently.
- Require explicit resolution for malformed or quarantined state. Never delete,
  replace, or overwrite it automatically.

## Fail and continue safely

- Treat a missing Hook assignment, failed stage, unreadable child task, or
  absent callback as a transport failure. Do not silently substitute another
  provider, model, app, direct API call, CLI process, or inherited root history.
- Multi-agent V1 is an explicit top-level session compatibility choice, not a
  per-spawn switch or silent fallback.
- The staged assignment briefly exists as plaintext in local user state before
  dispatch to the configured external provider and `deepseek-v4-flash` model.
  The Hook is a transport compatibility layer, not a confidential channel.