--- name: Alpha Evolve slug: alpha-evolve category: AI Engineering description: Alpha Evolve evolves a model or program with parallel SEARCH/REPLACE mutations, cascade-evaluated runs, and a MAP-Elites archive across islands. Use it for bounded, diversity-preserving search over code or ML experiments rather than a single refine loop. github: "https://github.com/gaasher/Agent-Loop-Skills/tree/main/loops/alpha-evolve" language: Python stars: 166 forks: 19 install: "npx degit https://github.com/gaasher/Agent-Loop-Skills/tree/main/loops/alpha-evolve ~/.claude/skills/alpha-evolve" installs_to: ~/.claude/skills/alpha-evolve source_path: loops/alpha-evolve/SKILL.md collection_size: 25 category_size: 3670 collection_url: "https://dirskills.com/collections/gaasher/Agent-Loop-Skills" added: 2026-09-08T05:34:35.035Z last_synced: 2026-09-08T05:34:35.035Z canonical_url: "https://dirskills.com/skills/alpha-evolve" --- # Alpha Evolve Alpha Evolve evolves a model or program with parallel SEARCH/REPLACE mutations, cascade-evaluated runs, and a MAP-Elites archive across islands. Use it for bounded, diversity-preserving search over code or ML experiments rather than a single refine loop. **Install:** ```bash npx degit https://github.com/gaasher/Agent-Loop-Skills/tree/main/loops/alpha-evolve ~/.claude/skills/alpha-evolve ``` ## README # Alpha-Evolve > Reference (read if you need the algorithm's details): AlphaEvolve — https://arxiv.org/abs/2506.13131 · > OpenEvolve (open-source impl) — https://github.com/algorithmicsuperintelligence/openevolve A **population-based evolutionary** loop over a program. The artifact is the editable model code; a **child** is one analysis-informed **SEARCH/REPLACE diff** to a parent, and the feedback signal is a **cascade-evaluated training run** (``, smoke→full). Children are placed in a **MAP-Elites archive across islands** (complexity × diversity axes), so a child survives by being either better or more novel, not just better. The discipline this enforces: **diversity is preserved, not collapsed** — diverse high performers co-exist instead of one local optimum winning. You are the controller: sample a parent + inspirations, spawn parallel Mutators to propose and evaluate children, place them, migrate between islands, checkpoint. Loops to a fixed compute budget or until interrupted. ## When to use Use this for parallel, diversity-preserving search over a model/program where many variants explore at once and the archive keeps the illuminated frontier. Default to broad island coverage; if quality stalls, bias selection toward exploiting top elites; if coverage stalls, bias toward empty cells. Not for the sequential autoresearch loops (one change at a time), and not for fixing a known anomaly. The cast (both in this folder): `roles/Mutator.md` produces + cascade-evaluates one child (the generation step); `schemas/result.schema.json` is the result a Mutator returns. ## Setup Resolve bindings interactively. If `loop.run.yaml` exists in the working dir, load it, confirm the values in one line, and skip to the loop. Otherwise: on Claude Code (the `AskUserQuestion` tool is available, `` = `claude-code`) infer a likely value for each binding and present it as the recommended option; on other hosts (`` = `other`) ask each as a quoted plain-text prompt. Then write `loop.run.yaml` (format: `examples/run.example.yaml`) and confirm the values before creating any other files. `` also decides execution: Claude Code spawns real `Agent` Mutators in parallel (capped at ``); other hosts degrade to running a generation's children serially (identical algorithm). **Probe the box first (mandatory — measure, never assume ``).** Record and report: - **CPU cores** → ``: `python3 -c "import os; print(os.cpu_count())"`. - **RAM** → ``: macOS `sysctl -n hw.memsize`; Linux `grep MemTotal /proc/meminfo`. - **Accelerator** → ``/``/``: `nvidia-smi --query-gpu=name,memory.total,count --format=csv` (NVIDIA); else macOS Apple GPU/MPS; else CPU-only. | binding | meaning | default | how to infer | |---|---|---|---| | `` + `` | scalar to optimize; min/maximize | — | ask; scan eval output for the reported metric | | `` / `` | command for one training run (the evaluator) | — | `pyproject.toml`/`.venv`/`uv`/README | | `` | the program being evolved (e.g. `model.py`, `config.yaml`); never the harness or data | — | ask explicitly — this is the code that gets mutated; do not default it (multi-select on Claude Code) | | `` | where `lae/` is created | `./sandbox` | — | | `` + `` | one full run's size: `time`/`epochs` + amount; the FIXED eval budget applied to every program | — | identify the duration key now (e.g. `train.epochs`) so the controller can override it | | `` | total compute = number of full training runs (or wall-clock minutes); the single cost dial | — | ask | | `` | parallel evaluations `C` | derived from the probe | CPU-only → `max(1, //4)`; single GPU/MPS → `1` (ask if more fit ``); multi-GPU → `` (pin one child/GPU) | `num_generations` is **derived**: `ceil( / )`. The cascade is **derived** from `` (not asked): smoke = ~1 epoch / a small subset, full = ``, gate = child's smoke `` ≥ parent's smoke. ``/``/eval split are FIXED — never mutation targets (a child may not "train longer" to look better); changing them means re-running the whole loop. **Advanced (opt-in).** Ask one yes/no: "Use defaults for the evolutionary settings, or customize?" Defaults are faithful to AlphaEvolve/OpenEvolve — use them and ask nothing more. Only on "customize" ask for each (showing the default as recommended): `num_islands` (4), `num_top` (3), `num_diverse` (2), `num_bins` (10), `migration_interval` (5), `diversity_reference_size` (10), `pop_per_island` (40), `seed` (42). Axes are fixed: complexity × diversity. See `examples/run.example.yaml` for the shape. Print the resolved bindings + the probe + derived `num_generations`, and **do not create files or launch until the user confirms**. Then initialise the sandbox (header rows only; `programs/` is created as children are evaluated): ``` /lae/ ├── archive.tsv ← current elites = program database + checkpoint ├── history.tsv ← append-only record of every child ├── leaderboard.md ← rendered UI └── programs/ ← one self-contained dir per program ``` ## The controller (loop) You maintain `num_islands` MAP-Elites maps in `archive.tsv`, the append-only `history.tsv`, running per-axis percentile stats, and `leaderboard.md`. **You are the sole writer of all shared logs** — Mutators only return results, so there are no write races. Copy this checklist and tick items off: - [ ] Setup done: probe recorded, bindings confirmed, sandbox initialised, `num_generations` derived. - [ ] GEN 0 — in each island, create the baseline program (a copy of ``) + optionally a few stochastic variants; cascade-evaluate; place in the archive. - [ ] Per generation: build EXACTLY `` tasks (round-robin island, seeded-rule parent, top `num_top` + `num_diverse` most-diverse inspirations); make each child dir by **copying** the parent program + harness. - [ ] Run the `C` Mutators (spawn-or-degrade), each with `roles/Mutator.md`, parent code, inspirations, parent artifacts, its child dir, and the smoke/full budgets. - [ ] For each returned child: append a `history.tsv` row; if `evaluated`, compute its niche → cell and place it in the island map iff `` is better (`kept=y`); record `smoke_dropped`/`crash` without placing. - [ ] Re-render `leaderboard.md`; checkpoint (`archive.tsv` is the checkpoint); print a status line. - [ ] Every `migration_interval` generations: ring-migrate top elites island k → k+1. - [ ] Stop at `` (reserve a little for synthesis), then synthesize the final report. **Niche computation (you do this, from a child's sandbox):** - **`complexity`** = trainable param count (fallback: total LOC of the editable files **+ any files the child added**), **log10-scaled**. - **`diversity`** = average normalized edit distance of the program's concatenated code (editable + added files) to a random sample of `diversity_reference_size` programs from its island (vs the baseline if the island is near-empty). Higher = more novel. - Normalize each axis with **running ~5th/95th percentiles** (not raw min/max, so one outlier can't collapse the range): `scaled = clamp01((v − p5)/(p95 − p5))`; `bin = min(num_bins−1, int(scaled × num_bins))`; `cell = (complexity_bin, diversity_bin)`. **Re-bin** existing elites when a percentile shifts enough to move an edge (keep the higher `` on collisions; the archive is small). **The Mutator's prompt (the sampler):** parent code + inspirations + the parent's rendered artifacts (``, per-class accuracy, loss curve, stderr) + the instruction to return one SEARCH/REPLACE diff. Single harness model — no LLM ensemble. The Mutator applies its diff in the child dir, cascade-evaluates at the FIXED `` (the controller injects/caps the duration key on the run command), and returns a result validated against `schemas/result.schema.json`: ```json {"child_id": "g3-i1-a2", "parent_id": "g1-i1-a0", "approach_summary": "add BatchNorm after conv2", "sandbox_path": "/lae/programs/g3-i1-a2", "status": "evaluated", "smoke_metric": 0.61, "metric": 0.71} ``` `status` ∈ {`evaluated`, `smoke_dropped`, `crash`}; `metric` is null unless `evaluated`. Mutators compute nothing about the archive — the controller derives every niche from the sandbox. **Program sandboxes.** A parallel population doesn't map onto branches, so every program is a self-contained, fully-runnable dir `/lae/programs//`; the archive references it by id. Build each child dir by **copying real files** (the parent's ``, then apply the diff, **plus the harness/entrypoint code it imports**) and evaluate from inside it (`cd && `). **Symlink only large read-only data**, never the entrypoint or any imported `.py`: Python resolves a symlinked script's `__file__` to the link target, so `sys.path[0]` becomes the original dir and the child's `model.py`/`dataset.py` are silently shadowed by the baselines — every architecture/data mutation becomes a no-op (tell-tale: identical loss curves across different "architectures"). **Isolation sanity gate:** the harness logs the param count / a code fingerprint; flag any child whose code changed but whose metric/loss curve is identical to its parent's (shadowed), and fix the sandbox before placing it. The repo working tree is never mutated. **Final synthesis.** Report the global-best program + its `lae/programs//` path, the illuminated complexity×diversity map (coverage + who won each region), per-island bests, and 2–3 notably diverse runners-up. ## Ledger All three logs live under `/lae/`, tab-separated, never commas in free text. The controller is the sole writer; resume from `archive.tsv` + `history.tsv` if interrupted. **`archive.tsv`** — current elites + checkpoint. Header `island cell metric child_id parent_id sandbox_path complexity diversity`: ``` island cell metric child_id parent_id sandbox_path complexity diversity 0 (2,7) 0.7100 g4-i0-a1 g2-i0-a3 lae/programs/g4-i0-a1 2.1M 0.71 ``` **`history.tsv`** — every child, append-only. Header `gen island parent_id child_id smoke_metric full_metric status kept cell`: ``` gen island parent_id child_id smoke_metric full_metric status kept cell 4 0 g2-i0-a3 g4-i0-a1 0.61 0.71 evaluated y (2,7) 4 1 g2-i1-a0 g4-i1-a2 0.40 - smoke_dropped n - ``` **`leaderboard.md`** — re-rendered each generation: global best + per-island coverage + the archive ranked by ``. Report the **best** program at stop (not the last), the archive coverage, and a few diverse runners-up. Leave `lae/` untracked. ## Constraints - A child works **only inside its own `lae/programs//` dir** — it may edit the copied `` and create new files there, but never modify any file outside it (the repo, the read-only harness, the data, other programs' dirs are ground truth or shared state). - **The controller is the sole writer** of `archive.tsv`/`history.tsv`/`leaderboard.md`, so parallel Mutators never race on the logs. - **`` comes from the probe + the user's confirmation** — never assume the box; pin one child per GPU on multi-GPU; if a run OOMs/thrashes, lower `C` and say so (don't rewrite a child's config to fit), because the box's limit is real and rewriting the child corrupts the comparison. - **`` (epochs/time), ``, and the eval/test split are FIXED and out-of-bounds for mutation.** The controller injects `` on every run, overriding any duration the child set — so "train longer" / change-the-metric / change-the-test-set can never win. Evolve the model/optimizer/data pipeline, not the compute or the scoring; comparability across programs depends on it. - **Never symlink the entrypoint or any imported `.py`** into a child dir (it shadows the child's code via `sys.path[0]`); copy harness code, symlink only data, and run the isolation sanity gate before placing a child — a shadowed result is a phantom. - Do not install new packages or modify the evaluation harness — `` is ground truth. - **Do not pause to ask "should I continue?"** Run until `` (reserving a little for synthesis) or interrupt; if coverage stalls bias toward empty cells, if quality stalls exploit top elites. A child that overruns its gate is killed and recorded as `crash`.