# @deepseek-ai/dsh-tool-workflow

The model-facing **`workflow` tool**: run a JavaScript orchestration script that fans out subagents, and return the script's final value. Pure schema + lifecycle shaping over [`ctx.workflows`](../workflow/README.md) — script parsing, execution, caps, and cancellation live behind the seam, so a hardened engine swaps in without touching what the model sees.

## What the model sees

Three parameters: `script` (required plain-JavaScript body with no `export const meta` statement), `meta` (required JSON identity with `name`/`description` and optional `whenToUse`/`phases`), and `args` (optional JSON object exposed to the script as the `args` global; wrap a bare list as a field so the wire schema stays honest). The tool description carries the complete authoring contract: hooks, semantics, and the supported schema subset. The plugin also contributes a `tool:<toolName>` system-prompt section carrying the usage policy — use the tool only on an explicit user ask for a workflow / large orchestration; prefer plain subagent calls for one or two delegations — per the convention that tool guidance ships with the tool plugin, never in the deployment persona.

## Lifecycle

Collection is SYNCHRONOUS this cut (like [`dsh-tool-subagent`](../../subagent/tool-subagent/README.md)): `execute` starts a run and awaits `run.result` inside a `try/finally` that always disposes the run, so the script and its children reach quiescence on every path. `exec.signal` is bridged to `run.cancel()` (including the already-aborted-before-start case). A non-`completed` stop reason maps to an `isError` result reporting the reason — never partial output as success; a parse/meta failure thrown synchronously by `start()` becomes an `isError` the model can correct from. The completed result renders the meta name, the agent count, and the return value as JSON, truncated at `maxResultChars` with an explicit notice.

## Render intent

Decided up front (per the [render-intent RFC](../../../docs/rfc/implemented/architecture/2026-07-02-tool-render-intent-union.md)): a `generic` card titled `workflow: <meta.name>`, read directly from the call's `meta` parameter (presentation is a pure function of args); the script text rides as `rawInput`. The result keeps the generic card.

## Config

| Key | Default | Meaning |
|---|---|---|
| `toolName` | `workflow` | The model-facing tool name to register. |
| `maxResultChars` | `50000` | Rendered-result ceiling; longer JSON is truncated with a notice. |

## Known Limitations and Deferred Work

- **The parent turn blocks until the whole workflow settles** — there is no background start/poll surface, and cancellation discards partial output as an error.
- **`args` must be an object and the result is bounded text** — callers wrap top-level arrays/scalars in a field, and JSON beyond `maxResultChars` is truncated rather than stored behind a retrieval handle.
- **Workflow policy is fixed per tool registration** — provider selection, caps, and tool name are deployment config, not model-call arguments.