dsh-subagent-effort

A DeepSeek Harness plugin that gives you per-call control over a subagent's thinking intensity.

The stock subagent / subagent_fork tools make the child inherit the session's reasoningEffort. This plugin adds one tool — subagent_effort(prompt, effort, cwd?, model?) — that runs a one-shot child with effort = low | high | max for that call only. The child otherwise joins your preset like a stock subagent: same persona, prompt sections, skill catalog and tools.

subagent_effort(prompt="List the files under src/", effort="low")      # mechanical work, cheap
subagent_effort(prompt="Refactor this module and explain the risks", effort="max")

Why it works

reasoningEffort is a first-class per-request field of the subagent seam, not a profile or preset setting:

• SubagentStartRequest.agentOptions documents provider / model / reasoning-effort / output-token overrides and requires the provider's agentOptions capability.
• The host's resolveChildAgentOptions(parent, requested, depth) spreads the requested options over the parent's route; an explicit effort survives both inheritance and a model switch.
• The LLM layer validates the effort against the model's advertised reasoning.efforts before any request and rejects unsupported values (UNSUPPORTED_REASONING_EFFORT) — no clamping, no silent fallback.

The plugin therefore registers one small provider implementing the 0.2.1 local activation contract (prepareContinuable) and advertises agentOptions: true. The host materializes the child, mounts the parent's preset composition and applies the requested effort. The plugin also pre-checks the model/effort pair through the llm service so a bad combination fails with a readable message instead of an opaque child error.

Requirements

• DeepSeek Harness 0.2.1 or newer (the activation API ctx.subagents.startActivation is mandatory).
• Node.js 22+ (the host ships its own runtime; this is only for node --check).
• A model that advertises reasoning efforts. With the DeepSeek account provider, deepseek-flash advertises low / high / max.

Install

From your DSH profile directory (for the desktop app: %USERPROFILE%\.dsh\profiles\desktop):

1. Add the dependency to package.json:

   "dependencies": {
     "dsh-subagent-effort": "file:C:/path/to/dsh-subagent-effort"
   }
   

   A published tarball or git URL works the same way (npm: / git+https: specifier).

2. Append the bundle so the plugin is mounted with the profile:

   "dsh": { "profile": { "bundles": [ "...", "dsh-subagent-effort" ] } }
   

3. Install and restart the app:

   pnpm install
   

Plugins are loaded at host startup — a restart is required after installing or updating. If you edit the plugin source in place, remember that a file: dependency is copied into node_modules, so re-run pnpm install (or copy the files) before restarting.

Configuration

The plugin reads its settings from the bundle row (all optional):

option	default	meaning
providerName	subagent-effort	provider name registered on ctx.subagents
toolName	subagent_effort	name of the model-facing tool

- id: dsh-subagent-effort
  name: dsh-subagent-effort
  config:
    toolName: subagent_effort

Tool

parameter	required	description
prompt	yes	Self-contained task for the child. It does not see this conversation.
effort	yes	low | high | max, validated against the model's advertised efforts.
model	no	Model id for the child (same provider as this session). Omit to inherit.
cwd	no	Absolute working directory for the child. Omit to inherit the session's.

The call is foreground: it waits for the child and returns its final text. Use low for mechanical, deterministic work (run a command, read files, apply a template), high for judgment without long reasoning chains, and max for cross-file reasoning, source-level diagnosis or design trade-offs.

How it works (implementation notes)

• apply() registers a provider implementing prepareContinuable — the host's local backend. No child agent is created by the plugin; the host materializes it and applies request.agentOptions.
• The tool builds { provider, label, signal, delivery: 'caller', request: { maxDepth, parent, prompt, agentOptions, cwd? } } and awaits ctx.subagents.startActivation(spec).
• delivery: 'caller' keeps the host from pushing a settlement notice into the parent's inbox — the tool result is the only delivery channel for a one-shot call.
• maxDepth is parentDepth + 1, so the child may not delegate further while a nested caller still works.
• Result first, dispose second: detaching the child before settling the result would cancel the turn.

Verified vs. not verified

Verified on DSH 0.2.1-rc.1 / 0.2.1-rc.2 (Windows desktop, 2026-10-17/18):

• the tool registers and appears in the tool surface;
• subagent_effort(effort="low") returns completed with the child's text;
• the child session records config.reasoningEffort: "low" (effort="max" likewise); the ids are 48d6d4fe-… (low) and 02d17f6e-… (max);
• an unsupported effort or an unknown model fails before delegation with the supported list.

Not verified:

• high was not separately recorded in a child session log (the value is accepted and goes through the same validation path).
• Only the Windows desktop host was exercised; other shells/hosts are untested.
• The tool is foreground-only; there is no background/job mode (use your host's background delegation for that).

License

MIT © 2026 tietoumiao