sakanaai/shinka-convert

Shinka Convert Skill

Use this skill to turn an existing project into a Shinka-ready task.

This is the alternative starting point to shinka-setup:

• shinka-setup: new task from natural-language task description
• shinka-convert: existing codebase to Shinka task conversion

After conversion, the user should still be able to use shinka-run.

When to Use

Invoke this skill when the user:

• Wants to optimize an existing script or repo with Shinka/ShinkaEvolve
• Mentions adapting current code to Shinka output signatures, metrics.json, correct.json, or EVOLVE-BLOCK markers
• Wants a sidecar Shinka task generated from the current working directory

Do not use this skill when:

• The user wants a brand-new task scaffold from only a natural-language description
• evaluate.py and initial.<ext> already exist and the user only wants to launch evolution; use shinka-run

User Inputs

Start from freeform instructions, then ask follow-ups only if high-impact details are missing.

Collect:

• What behavior or file/function to optimize
• Score direction and main metric
• Constraints: correctness, runtime, memory, determinism, style, allowed edits
• Whether original source must remain untouched
• Any required data/assets/dependencies

Default Output

Generate a sidecar task directory at ./shinka_task/ unless the user requests another path.

The task directory should contain:

• evaluate.py
• run_evo.py
• shinka.yaml
• initial.<ext>
• A copied snapshot of the minimal runnable source subtree needed for evaluation

Do not edit the original source tree unless the user explicitly requests in-place conversion.

Workflow

1. Inspect the current working directory.
   • Identify language, entrypoints, package/module layout, dependencies, and current outputs.
   • Prefer concrete evidence from the code over guesses.
2. Infer the evolvable region from the user's instructions.
   • If ambiguous, ask targeted follow-ups.
   • Keep the mutable region as small as practical.
3. Choose the minimal runnable snapshot scope.
   • Copy only the source subtree needed to execute the task in isolation.
   • Avoid repo-wide snapshots unless imports/runtime make that necessary.
4. Create the sidecar task directory.
   • Default: ./shinka_task/
   • Avoid overwriting an existing task dir without consent.
5. Rewrite the snapshot into a stable Shinka contract.
   • Preserve original behavior outside the evolvable region.
   • Keep CLI behavior intact where practical.
   • Ensure the evolvable candidate entry file is named initial.<ext> so shinka-run can detect it.
   • Add tight EVOLVE-BLOCK-START / EVOLVE-BLOCK-END markers.
6. Generate the evaluator path.
   • Python: prefer exposing run_experiment(...) and use run_shinka_eval.
   • Non-Python: use subprocess and write metrics.json plus correct.json.
7. Generate run_evo.py and shinka.yaml.
   • Ensure init_program_path and language match the candidate file.
   • Keep the output directly compatible with shinka-run.
8. Smoke test before handoff.
   • Run python evaluate.py --program_path <initial file> --results_dir /tmp/shinka_convert_smoke
   • Confirm evaluator runs without exceptions.
   • Confirm required metrics/correctness outputs are written.
9. Ask the user for the next step.
   • Either run evolution manually
   • Or use the shinka-run skill

Conversion Strategy by Language

Python

• Preferred path: expose run_experiment(...) in the snapshot and evaluate via run_shinka_eval
• If the existing code is CLI-only, add a thin wrapper in the snapshot rather than forcing a subprocess evaluator unless imports are too brittle
• Keep imports relative to the copied task snapshot stable

Non-Python

• Keep the candidate program executable in its own runtime
• Use Python evaluate.py as the Shinka entrypoint
• Write metrics.json and correct.json in results_dir

Required Evaluator Contract

Metrics must include:

• combined_score
• public
• private
• extra_data
• text_feedback

Correctness must include:

• correct
• error

Higher combined_score values indicate better performance unless the user explicitly defines an inverted metric that you transform during aggregation.

Python Conversion Template

Prefer shaping the copied program like this:

from __future__ import annotations

# EVOLVE-BLOCK-START
def optimize_me(...):
    ...
# EVOLVE-BLOCK-END

def run_experiment(random_seed: int | None = None, **kwargs):
    ...
    return score, text_feedback

And the evaluator:

from shinka.core import run_shinka_eval

def main(program_path: str, results_dir: str):
    metrics, correct, err = run_shinka_eval(
        program_path=program_path,
        results_dir=results_dir,
        experiment_fn_name="run_experiment",
        num_runs=3,
        get_experiment_kwargs=get_kwargs,
        aggregate_metrics_fn=aggregate_fn,
        validate_fn=validate_fn,
    )
    if not correct:
        raise RuntimeError(err or "Evaluation failed")

Non-Python Conversion Template

Use evaluate.py to run the candidate and write outputs:

import json
import os
from pathlib import Path

def main(program_path: str, results_dir: str):
    os.makedirs(results_dir, exist_ok=True)
    metrics = {
        "combined_score": 0.0,
        "public": {},
        "private": {},
        "extra_data": {},
        "text_feedback": "",
    }
    correct = {"correct": False, "error": ""}

    (Path(results_dir) / "metrics.json").write_text(json.dumps(metrics, indent=2))
    (Path(results_dir) / "correct.json").write_text(json.dumps(correct, indent=2))

Bundled Assets

• Use scripts/run_evo.py as the starting runner template
• Use scripts/shinka.yaml as the starting config template

Notes

• Keep evolve regions tight; do not make the whole project mutable by default
• Preserve correctness checks outside the evolve region where possible
• Prefer deterministic evaluation and stable seeds
• If the converted task is ready, offer to continue with shinka-run