[!CAUTION]
Claude Code only. CoalTipple's routing only actuates where an agent can pick a spawned worker's model + effort. Today that is Claude Code. Antigravity does NOT work -- its subagents inherit the parent's model (no per-spawn model parameter, no separate effort knob), so routing cannot actuate there. Other platforms (Codex, Cursor, ...) are under monthly review.

🚂 What it is

A tipple is the sorting-and-rail-switching station of a coal mine. This tool switches rails for prompts across models (alongside CoalMine).

You are main. CoalTipple decides, per task, whether to:

Routing logic lives inside SKILL.md — the model reads and routes natively. No background daemon.

🤖 Compatibility

• Claude Code (validated live across the 2.1.x line): Built Claude-Code-first and run end-to-end across all model tiers (Haiku, Sonnet, Opus). Routing degrades safe on any CC version — an unfamiliar model classifies strong, a failed spawn falls, and the platform resolves each alias to its current best model at spawn-time (the ranking is the alias floor + pins — nothing to enumerate).
• Routing actuates on Claude Code only: CT needs a platform where an agent can pick a spawned worker's model + effort. CC's Agent/Task tool takes a model param -- that is the requirement.
• Subagent-capable != qualifies: a platform can spawn workers yet give the agent no model choice (e.g. Antigravity, where the worker inherits the parent's model). There CT does not cleanly self-degrade -- a weak main hallucinates a delegate-down it cannot perform -- so CT is gated to CC. Other platforms (Cursor · Zed · OpenCode · Devin · Kiro · Copilot CLI, …) are under monthly review — see Install → Other platforms for the current matrix.

🚀 Install

CoalTipple installs on Claude Code only — routing actuates only where an agent can pick a spawned worker's model + effort, and Claude Code's Agent/Task tool is the one that takes a model parameter.

Claude Code — plugin

claude plugin marketplace add TheColliery/CoalTipple
claude plugin install coaltipple@coaltipple
# Restart Claude Code to load the /coaltipple commands (stats | off | memory)

Optional per-project config override: <project>/.claude/.coaltipple.json.

Other platforms — no install (routing cannot actuate)

There is deliberately no file-copy or install.mjs path for other agents: a spawned worker inherits the parent model, so CoalTipple has no worker model + effort to route with (see Compatibility for the full reason).

• Antigravity — verified non-actuating (2026-06-16): no per-spawn model parameter, no separate effort knob. Copying the files in would only let a weak main hallucinate a delegation it cannot perform, so CT does not install here.
• Codex · Gemini CLI · Cline · Windsurf — no worker model-pick → not supported.
• Cursor — reports a worker model param but it is unverified; a monitored candidate under monthly review (verify the spawn schema first), not a supported install today.
• Zed · OpenCode · Devin · Kiro · Copilot CLI — candidates — docs-verified 2026-07-13; a live spawn-schema verify on a real install is REQUIRED before any adapter (the Antigravity burn rule: docs-claimed ≠ actuating). What the docs show: Zed agent.subagent_model · OpenCode per-agent model (provider/model-id) · Devin subagent model frontmatter (+ an Adaptive auto-router) · Kiro a subagent model attribute · Copilot CLI partial (a profile pin works, but the Task-tool model param has an open upstream bug and a cost-guard silently downgrades sub models).
• Adapter design, locked ahead of any verify: pre-provisioned pins — define per-tier pinned subagents (the Codex pattern: per-agent config files carrying a pinned model), so routing = picking the agent, no per-spawn model param needed; it ships only after a live schema verify on a real install.
• claude.ai — the ZIP-upload skill path is for read/analyze skills only; CoalTipple actuates model routing, so it does not apply.

Verify (from clone)

node scripts/verify.mjs   # validates config, schemas, plugin files
node scripts/test.mjs     # runs zero-dependency unit tests

🎛️ The Two Knobs

Routing adjusts two independent knobs (always raise effort before tier):

• TIER tracks difficulty/sensitivity; EFFORT tracks output size. A short cryptographic function wants a high tier but low effort. A large mechanical template wants a cheap tier but high effort.

The qualityBar Staircase

qualityBar (0–100, default 60) defines the acceptable quality threshold:

1. The task's grade picks the starting tier (cheapest possible).
2. The worker runs, and output is verified against the task contract.
3. Passes → done. Fails → climb one rung. Out of attempts/fails hard → jump to top tier.

• Tune qualityBar by risk: raise (~85) for critical logic; lower (~45) for quick drafts.

🛡️ Routing the Work Safely

• No Down-Delegation for Sensitive Tasks: Cryptography, auth, payments, and security paths are forced to the heavy tier based on keywords. They never fall to cheap tiers, even under quota limits — and a modelTiers pin naming a known-weaker model (e.g. haiku) can never satisfy that floor either.
• Overhead Floor: Tasks below delegateMinLines (default 120) stay on main to avoid spawn overhead.
• Prose Preservation: User-facing writing and translation stay on main to protect voice.
• Verify, Do Not Eyeball: Output merges require passing objective checks (qaOnMerge: strict/standard/off).
• Workers are Leaves: By policy a worker is given a bounded task contract and returns to main rather than spawning its own workers — routing stays depth-0 whether or not the platform allows nesting.

Damage Control

• Isolation: Uses git worktree-isolation (or local .claude/.coaltipple/proposed/ sandbox with state.json journaling) to protect files from mid-run failures.
• Rate Limits: Automatically falls back to the next available tier on limit-hits, but never below a sensitive task's minimum tier.
• Side Effects: Commands with external side-effects (e.g. bash mutations, commits) are never delegated.

🔒 The Lock — Safe Routing States

The Lock guarantees CoalTipple is only ever in one of two states: routing correctly or routing off.

• Always Buildable: The ranking is the alias floor haiku < sonnet < opus (→ low/mid/heavy, reasoning = opus) overlaid with your modelTiers pins — a constant, no enumeration. Unknown models default to heavy.
• Validity-Gated: Checks ranking schema, hash, and completeness before writing.
• Fails Safe: Bypasses routing if the model ranking is broken.
• Spawn-Time Resolution: The platform resolves each alias to its current best model at spawn-time, and a failed spawn falls to the next available tier — so the floor never goes stale and there is no refresh cadence.

🧠 Memory Anchor

Workers start context-fresh. A memory anchor file gives a fresh worker project context.

• If contextFiles is empty, CoalTipple auto-loads CLAUDE.md / AGENTS.md.
• Offers once to set up an anchor on new projects. Manage manually via /coaltipple memory.

⚙️ Configure

Everything is tunable in .coaltipple.json — a global ~/.claude/.coaltipple.json overlaid per key by the project <gitroot>/.claude/.coaltipple.json (project wins), so you can tune or shut off a globally-installed skill per project (off-switch: enableRouting: false) — a skill you don't need in a given project stops loading (and burning tokens) there. Ships zero-config with optimal defaults. The high-impact keys:

Full key reference: every key + default lives in scripts/lib/config-schema.mjs and the commented template platform-configs/.coaltipple.json — or run node scripts/configure.mjs --help.

📊 Benchmark

We evaluate the final output correctness after the main escalates one rung, and the token savings of delegating mechanical bulk down — each dated, on small honest samples, in the linked record so a copied number cannot drift.

• ON-vs-OFF (paired, 2026-07-03, v1.0.23): the same 4 tasks at every tier (36 runs, K=3, Haiku 4.5/Sonnet 5/Opus 4.8) — routing ON scored 4/4 task quality on both baselines; OFF scored 3/4 on both, failing a DIFFERENT task each (an Opus main fails the boring spec's letter; a Sonnet main fails the sensitive legal nuance). From an Opus main ON is also ~23% cheaper; from a Sonnet main it is cost-neutral and removes a liability-shifting translation error.

Full harnesses, per-task scoring, the quality-vs-tier matrix, routing-savings history, and every honest-scope caveat live in the series umbrella: TheColliery/.github/benchmarks/CoalTipple (RESULTS.md · ROUTING-SAVINGS.md).

🧭 Part of TheColliery

CoalTipple shares its engineering doctrine with CoalMine, CoalBoard, CoalHearth (session warm-resume), CoalFace (fan-out discipline), CoalWash (memory defrag), and CoalLedger (docs health): Phoenix-13 hooks (zero-dependency, no network, fail-silent, no child processes, deterministic), single-source-of-truth config schemas, and a strict no-overkill discipline. Install one and it stands alone; install all and they compose without conflict.

📄 License

Apache License 2.0. See LICENSE for details.