dsh-agent-router

A DeepSeek Harness plugin that picks a subagent's provider and model once, at delegation time, from a short list of keyword rules you write. No classifier, no scoring: the first rule whose keyword appears in the delegation label or prompt wins, and a delegation no rule claims runs exactly as it would without the plugin.

It wraps the official subagents.startActivation service, so the child still goes through DSH's own capacity, cancellation, result delivery, persistence and cleanup. It registers no tools and changes nothing for the root agent.

Install

Requires pnpm, which dsh plugin shells out to.

From source:

git clone https://github.com/gengwg/dsh-agent-router
cd dsh-agent-router
dsh plugin --profile web add "$PWD"

The package declares dsh.bundle, so dsh plugin add joins it to the profile's bundle stack. Restart dsh to load it. It activates with an empty rule list, which routes nothing.

Configure

Rules live in the profile's ~/.dsh/profiles/<profile>/cordis.patch.yml under the agent-router entry. Each rule names the keywords that select it and the route to apply:

- id: agent-router
  name: dsh-agent-router
  config:
    rules:
      - name: research
        keywords: [investigate, research, compare]
        route:
          provider: openrouter
          model: deepseek/deepseek-v4-pro
          reasoningEffort: high
      - name: routine
        keywords: [typo, rename, format]
        route:
          provider: openrouter
          model: deepseek/deepseek-v4-flash

Field	Required	Meaning
keywords	yes	Non-empty list of case-insensitive substrings, matched against the delegation label and prompt text.
route.provider, route.model	yes	The child's provider and model. Must already be an allowed route in your DSH setup; the plugin cannot grant access.
route.reasoningEffort	no	Set on the child. When omitted, a caller-supplied effort is dropped so it does not carry onto a different model.
name	no	Label used in the decision record.
overrideExplicit	no	Default false: a rule never replaces a route the caller set explicitly (provider, model or reasoningEffort in agentOptions). Set true to let this rule win anyway.

A malformed rule fails the plugin at load time with the offending path (for example rules.0.match: unknown rule key), so a typo cannot silently route or silently pass everything through.

Behaviour

• First match wins, in config order. Matching is a lowercase substring test on label + "\n" + prompt text; an empty keyword never matches.
• Explicit routes are preserved. If the delegating agent asked for a provider/model itself, rules without overrideExplicit leave it alone.
• No fallback route. A delegation no rule matches passes through untouched, so DSH's own inheritance applies.
• Non-route options survive. cwd, token limits and other agentOptions are kept; only provider, model and reasoningEffort are rewritten.
• Providers that cannot take agentOptions are left alone. Out-of-process backends (for example ACP) declare capabilities.agentOptions: false; routing them would fail the delegation, so they pass through untouched.
• Pure decisions. decide(rules, { label, promptText, requested }) is exported and returns { action, reason, rule, matchedKeyword, agentOptions? }, so you can dry-run a rule set in a script before enabling it. Pass rules through validateConfig(config).rules first; decide assumes the validated shape.

Limitations

• Routes are applied after the subagent tool's own preflight, so the plugin does not re-check a configured route against DSH's model-selection allowlist. Only configure routes your profile already permits. reasoningEffort is likewise passed on as written; an unknown effort id is rejected by DSH, not at load.
• Routing happens when a child is created. A running child's model is never changed, and failures (quota, auth, rate limits) are not rerouted; pair with a fallback plugin if you need that.
• Keyword matching is deliberately simple. If you need classification, write the classifier and feed its result in as a label.

Development

npm test

The unit tests need Node 22.18+ (TypeScript test files run via type stripping). Two tests load the plugin through DSH's real Cordis loader; they find a global DSH install automatically or via DSH_NODE_MODULES=<dsh>/node_modules, and are skipped when none is present. Tested against DSH 0.2.1-rc.5.

License

MIT