Model Routing

Install, update, or remove a per-project model-delegation rule. The rule is a plain .claude/rules/ file: it loads at session start in that project only, needs no plugin installed to keep working, and is removed by deleting the file.

The install has three independent layers. The base rule is standalone — no external tool, no CLI. Two layers are opt-in: pre-shaped agents and an agent-state feedback section. Add only what the project wants; the base is complete on its own.

Design rationale: VISION.md "route to the cheapest capable model" — decomposition quality and model tiering are complements; well-scoped leaf tasks don't need the frontier model.

Install

1. Determine the project root: the git repository root, or the working directory if not in a git repo. If the user names a different target project, use that.
2. Base rule (always). Read references/model-delegation.md (relative to this skill) and write its content verbatim to /.claude/rules/model-delegation.md, creating .claude/rules/ if needed. Verbatim copy keeps installs identical across projects — do not regenerate or paraphrase the rule text. This layer is fully standalone; nothing below is required for it to work.
3. If the target file already exists and differs, show the user the diff and ask before overwriting — it may carry local edits.
4. Agents layer (opt-in). Ask whether to also install the pre-shaped delegation agents (or install without asking if the user said "with agents"). If yes, copy verbatim references/agents/fast-executor.md and references/agents/task-coder.md to /.claude/agents/, same diff-and-confirm treatment. These give delegation targets tailored execute-to-spec system prompts instead of a bare model override; the rule prefers them automatically when present.
5. Feedback layer (opt-in). Ask whether to add agent-state outcome recording (or add it if the user said "with feedback" / "with agent-state"). Only worth it if they have or will install the agent-state CLI. If yes, append the contents of references/feedback-addon.md verbatim to the installed /.claude/rules/model-delegation.md. Do NOT add this by default — it is always-loaded text that only matters when the CLI is present, so keep it out of projects that won't use it.
6. Tell the user which layers were installed: the rule (and any agents) load automatically at the next session start. For the current session, adopt the rule's behavior immediately since you have just read it.

Update

Same as install; step 3's diff-and-confirm handles the existing files. To add the feedback layer to an already-installed base rule, append references/feedback-addon.md (skip if that section is already present).

Remove

Delete /.claude/rules/model-delegation.md, and /.claude/agents/fast-executor.md / task-coder.md if they were installed. Nothing else to clean up.

What the rule says

Delegation criteria in brief (full text in references/model-delegation.md): route tasks that are well-specified, mechanical, and verifiable to the cheapest capable model in a subagent; keep design, ambiguity, user interaction, and verification of returned work in the main loop on the strongest model. Tiers are named only as examples so the rule survives model-lineup changes. The base rule stops there — no external dependency.

The optional feedback layer (references/feedback-addon.md) adds agent-state delegation record ... after verification so acceptance rates per model/domain can tune the criteria over time. It is opt-in precisely because it is always-loaded text that only pays off when the agent-state CLI is installed.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: fblissjr
• Source: fblissjr/fb-claude-skills
• License: Apache-2.0

Install and usage instructions live in the source repository linked above.