spawnllm 0.3.1

Subshell + MLX LLM-calling backends (Claude/Codex CLI, local MLX) shared across tools.

spawnllm

Subshell + MLX LLM-calling backends (Claude/Codex CLI, local MLX) shared across tools.

spawnllm centralizes the LLM-calling plumbing that small tools keep re-inventing: driving the claude and codex CLIs as subshells — with structured Pydantic output, model tiers, and faithful error capture — and running local Apple-Silicon MLX models with adapter fusion, prompt-cache reuse, and batched generation. Depend on it once and each tool keeps only its domain logic instead of its own copy of the backends.

Install

No install needed — run everything through uvx:

uvx spawnllm --help

uvx fetches spawnllm into a throwaway environment and runs it. To add it to a project instead:

uv add spawnllm

For the local MLX engine (Apple Silicon only), pull the extra:

uv add "spawnllm[mlx]"

Quickstart

See which backends are installed and authenticated, and which one auto-selection picks:

uvx spawnllm status

claude: ready
codex: ready
selected: claude

Make a request by passing a prompt as the argument, or piping it over stdin:

uvx spawnllm call --backend claude "What is 2+2? Reply with just the number."

4

--model small|medium|large swaps the tier, which each backend maps to a concrete model. The claude backend resolves small to Haiku, medium to Sonnet, and large to Opus. Add --agent to let the call use tools.

From Python

call runs one request and returns the response. With no backend, it auto-selects the first installed, authenticated CLI:

from spawnllm import call

print(call("Reply with just the word: pong"))
# pong

Pin a backend and tier explicitly, or pass a Pydantic model to get a validated object back instead of text:

from pydantic import BaseModel

from spawnllm import call, ClaudeCliBackend


class Capital(BaseModel):
    country: str
    capital: str


result = call(
    "What is the capital of France?",
    backend=ClaudeCliBackend(),
    model="large",
    response_model=Capital,
)
print(result.capital)  # Paris

When you don't pin a backend, set specialty= to scope auto-selection by task. The debugging and review specialties route to Codex, and general routes to Claude.

What problems does this solve?

Every tool that shells out to claude or codex rebuilds the same plumbing: argv construction, stdin/stdout piping, stderr teeing, and turning non-zero exits into useful errors. spawnllm holds it once.

Structured output is boilerplate too. A Pydantic model becomes a JSON-schema constraint and a parsed, validated result, identically for both CLI backends.

Local MLX is fiddly. Adapter fusion, prompt-cache reuse, worker-thread lifecycle, and batched single-token generation live behind one engine instead of in every consumer.

Behavior drift goes away with the duplication: two tools that call the same models stay byte-for-byte consistent because they share the backend layer, not a pair of diverging copies.

Docs

Read the docs for the full guide and API reference.