coaxer 0.2.18

Evals-first prompt optimization. Label examples, get better prompts.

coaxer

Label examples. Derive the prompt. Consume it as a string.

Documentation

Motivation

Writing prompts by hand is slow, and the prose grows brittle as cases accumulate. Coaxer flips it: label examples of the behavior you want, derive the prompt from those labels -- when it drifts, add more labels instead of rewriting.

Labels are the source of truth. The prompt is a build artifact.

Install

uv add coaxer

Label

One directory per record. record.json holds scalar fields; large text and binary inputs live as sibling files.

labels/repo-classification/
  _schema.json              # optional: field descriptions + types + enums
  0001/
    record.json             # {id, inputs: {readme, stars, ...}, output}
    readme.md               # large text referenced from record.json
  0002/
    ...

_schema.json is optional. Without it, field names and types are inferred from the records.

{
  "inputs": {
    "readme": {"desc": "Project README markdown"},
    "stars": {"desc": "GitHub star count", "type": "int"}
  },
  "output": {
    "desc": "Curated collection vs organic project",
    "type": "enum",
    "values": ["true", "false"]
  }
}

Distill

coax labels/repo-classification --out prompts/repo-classification

Writes four files to the output folder:

File	Purpose
prompt.jinja	Human-readable Jinja template with {{ field }} slots.
meta.json	Compile metadata: compiled_at, example_count, label_hash, schema.
dspy.json	DSPy program state (only when --optimizer gepa).
history.jsonl	Append-only compile log.

Optimizer is opt-in. --optimizer gepa runs DSPy 3's GEPA pass and requires an LLM credential. The default (--optimizer none) emits a schema-derived template and is reproducible without network.

Consume

from coaxer import CoaxedPrompt

p = CoaxedPrompt("prompts/repo-classification", role="classifier")  # bind defaults
filled = p(readme=new_readme, stars=1200)                         # render at call time

• CoaxedPrompt(path, **bound) — str subclass; __new__ reads prompt.jinja.
• str(p) — raw template.
• p(**vars) — Jinja2 StrictUndefined render; missing variables raise.
• Call-time variables override bound defaults.

Because CoaxedPrompt is a str, it drops in anywhere a string is accepted (logging, OpenAI SDK messages, Anthropic SDK, DSPy signatures built externally, etc.).

Compile LLMs

AgentLM routes compile calls through the Anthropic Agent SDK (Claude Code). OpenAILM hits any OpenAI-compatible endpoint (Ollama, vLLM, OpenAI).

from coaxer import AgentLM, OpenAILM

lm = AgentLM()                                # Claude via Agent SDK
lm = OpenAILM(model="llama3")                 # Ollama
lm = OpenAILM(model="gpt-4o", base_url="https://api.openai.com/v1", api_key="sk-...")

Both pass keyword arguments through to their underlying client.

Caching

Pass a cachetta instance to file-back LM responses:

from cachetta import Cachetta
from coaxer import AgentLM

cache = Cachetta(path=lambda prompt, **kw: f"cache/{prompt}.pkl", duration="7d")
lm = AgentLM(cache=cache)

Install with the cache extra: uv add "coaxer[cache]".

Development

uv sync --extra dev
uv run just test-unit   # Unit tests
uv run just ci          # Full CI (lint + format + typecheck + tests)