Cheaplane 🛣️

Keep your premium subscription on the main thread. Offload the grunt work to cheap models — Cheaplane even picks the right one for you. Stop burning premium tokens on boilerplate.

Cheaplane is a tiny single-file MCP server (~250 lines, stdlib + mcp only) that gives your main agent — e.g. Claude Code on a Max subscription — one extra tool: delegate. Your agent keeps doing the thinking (planning, architecture, final review) and hands replaceable grunt work — boilerplate code, formatting, translation, summarizing long docs — to cheap models behind a local LiteLLM proxy (DeepSeek, Kimi, Qwen, …). Think of it as a cheap intern for your premium agent — it churns out the boring parts while you keep thinking.

The trick that makes it safe: the delegated calls and your subscription live in physically separate processes and never share credentials. (why that matters ⬇️)

The trick that makes it effortless: auto-routing. delegate(task) picks the right cheap model from the task itself — code → DeepSeek, long docs → Kimi, Chinese → Qwen. (how ⬇️)

The trick that makes it stick: a per-turn reminder hook so your agent doesn't forget the tool exists — the part most "delegate" tools skip. And a savings ledger shows you what it kept off your quota.

See it in action — your agent hands a chore over; auto-routing sends it to the cheap code model:

delegate("convert to a TypeScript interface: {id, name, email, isAdmin, roles[]}")

interface User {
  id: number;
  name: string;
  email: string;
  isAdmin: boolean;
  roles: string[];
}

_{↑ a real call's output — not a mockup, and no model picked by hand. That token cost ~90× less than your premium model, and your subscription quota never moved.}

The problem

Premium models earn their price on hard problems — but every token counts against your plan, and you burn through quota on churn: reformatting JSON, translating UI strings, summarizing a doc you'll read once. The usual "just use a cheap model" setups force an ugly choice:

• Downgrade the whole agent → you lose main-thread quality on the work that actually matters.
• Route everything through an API key → you stop using the subscription you're already paying for.

Cheaplane keeps the sweet spot: premium main thread for judgment + cheap models for the churn + billing that physically can't cross.

How Cheaplane compares

The popular 2026 move is to swap your whole agent onto a cheap model (DeepClaude-style). Great for raw cost — but it downgrades the thread you actually think with, breaks your other MCP tools, and doesn't even apply if you're on a Pro/Max subscription. Cheaplane takes the opposite bet:

_{Comparison reflects how backend-swap setups (DeepClaude-style) behaved per public reports in mid-2026; specifics vary by tool and can change.}

How cheap is "cheap"?

The grunt work is the easy part — paying premium rates for it is pure waste. Per million tokens (public list prices, mid-2026):

That's an output token costing ~$25 on Opus vs ~$0.28 on DeepSeek — about 90× more for work that doesn't need the smarts. You're on a subscription, so you don't pay that $25 directly — your main thread spends quota, not dollars. That's the whole point: every routine task you offload is premium quota you keep for the hard problems. (Summarizing a 40-page doc on DeepSeek Flash runs ~$0.005 — your quota never even notices.)

_{Prices are public list rates, mid-2026, and vary by tier/caching — check each provider. The stable takeaway is the order-of-magnitude gap, not an exact dollar saving.}

Billing isolation (the whole point)

Most "save money" hacks blur your bills together. Cheaplane keeps them physically apart:

flowchart LR
    A["Main agent<br/>premium subscription"] -->|"delegate(task)"| B["Cheaplane MCP<br/>own process, own key"]
    B -->|HTTP| C["LiteLLM proxy<br/>localhost:4000"]
    C --> D["DeepSeek / Kimi / Qwen<br/>cheap, pay-per-use"]

The Cheaplane process never imports your subscription provider's SDK, never reads its auth, never touches its OAuth token. It knows exactly one thing: an HTTP endpoint (your proxy) and its key. Your main thread bills to your subscription; delegated calls bill to your cheap proxy. The two can't cross — not by policy, by architecture.

Quick start

Fastest path — Claude Code, one script:

git clone https://github.com/millennialdreamer/cheaplane && cd cheaplane
cp litellm.yaml.example litellm.yaml          # then: export DEEPSEEK_API_KEY=sk-...
litellm --config litellm.yaml &               # start the cheap-model proxy on :4000
bash setup.sh                                 # deps + register MCP + reminder hook + verify

setup.sh is idempotent (safe to re-run): it installs deps, registers the delegate MCP server with Claude Code, installs the per-turn reminder hook, and verifies the chain end-to-end. Then start a fresh Claude Code session — done.

Prefer a package? Cheaplane is on PyPI — no clone, no path to hard-code:

pip install cheaplane          # or: uvx cheaplane  /  pipx install cheaplane
claude mcp add delegate cheaplane

You still want the proxy from step 1 below, and the reminder hook is worth it — that part needs the repo.

# litellm.yaml — exposes DeepSeek under the model_name "deepseek"
model_list:
  - model_name: deepseek
    litellm_params:
      model: deepseek/deepseek-chat        # swap for any provider/model LiteLLM supports
      api_key: os.environ/DEEPSEEK_API_KEY

pip install 'litellm[proxy]'
litellm --config litellm.yaml        # serves http://localhost:4000

pip install cheaplane        # installs a `cheaplane` command; that's the whole install

git clone https://github.com/millennialdreamer/cheaplane && cd cheaplane
uv sync     # or:  python -m venv .venv && .venv/bin/pip install mcp

{
  "mcpServers": {
    "delegate": { "command": "cheaplane" }
  }
}

{
  "mcpServers": {
    "delegate": {
      "command": "uv",
      "args": ["run", "--directory", "/ABSOLUTE/PATH/TO/cheaplane", "python", "server.py"]
    }
  }
}

uv run python probe.py
# ✅ chain works (main → MCP → cheap model → back)

Using delegate

Your agent now has delegate(task) — routing is automatic; override only when you want to:

delegate("convert this JSON to a TypeScript interface: …")      #  auto → deepseek (code)
delegate("summarize this 40-page contract: …")                  #  auto → kimi (very long input)
delegate("…Chinese text in the task auto-routes here…")        #  auto → qwen (Chinese copy)
delegate("translate these UI strings to Japanese", "flash")     #  explicit alias still wins