yoyo-evolve is a terminal coding agent that reads and changes its own Rust source code, runs tests, and commits its improvements. It is for users who want an autonomous agent that can navigate codebases, edit multiple files, run tests, manage Git, and recover from failures. The catalogue entries are skills for working with this coding agent.
Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add yologdev/yoyo-evolve --skill skill-evolvegit clone --depth 1 https://github.com/yologdev/yoyo-evolveWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/yologdev/yoyo-evolve/skill-evolve)<a href="https://agentmods.dev/skills/yologdev/yoyo-evolve/skill-evolve"><img src="https://agentmods.dev/badge/skills/yologdev/yoyo-evolve/skill-evolve/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/yologdev/yoyo-evolve/skill-evolve"><img src="https://agentmods.dev/badge/skills/yologdev/yoyo-evolve/skill-evolve.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Agent Snooping · line 46 Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
- medium Agent Snooping · line 51 Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00021 | $0.08280 |
| Opus 5.5 | $0.00008 | $0.03312 |
| Sonnet 5.5 | $0.00004 | $0.01656 |
| Haiku 4.5 | $0.00002 | $0.00828 |
Grade A, and why
skill-evolve scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 508 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill Evolution
You are evolving your own skills. This is the only skill that modifies other skills. Treat every cycle with care — what you write here shapes how every future yoyo session behaves.
When to use
Only when invoked via scripts/skill_evolve.sh. The harness gates on session count and cooldown; it sets up the audit-log worktree and composes the prompt. Do not run this skill opportunistically from inside a normal evolve session.
Hard rules (read first, every cycle)
These three rules cannot be violated. Each cycle either honors all three or writes a refused event and exits.
HARD RULE #1 — Eligible targets only (allow-list)
You may refine, deprecate, or retire only skills whose frontmatter declares origin: yoyo. Any other value, OR a missing origin: field, means the skill is off-limits. This is an allow-list: silence means "don't touch."
Three categories of skill exist:
origin: value |
Source | You may edit? |
|---|---|---|
creator |
Written by the human creator (Yuanhao or a fork creator) | Never |
yoyo |
Written by yoyo (this skill, or in past evolutions like social/family/release) |
Yes — eligible |
marketplace, gh:user/repo, etc. |
Installed from a third party | Never — upstream owns it |
| (missing) | Unknown provenance | Never (default-safe) |
Today the eligible set is exactly the skills whose SKILL.md declares origin: yoyo:
socialfamilyrelease- any skill you previously spawned (which inherit
origin: yoyofrom the Create template)
Defense in depth: if a skill has core: true set, refuse even if origin: yoyo is also somehow present. The two flags should never co-occur, but the conservative move is to honor the deny-flag.
If a recurring pattern suggests a non-eligible skill needs change (e.g., a core skill, or an installed marketplace skill), do not edit it. Instead, write a learning to memory/learnings.jsonl with source: "skill-evolve" and a clear pattern_key, and append a meta-suggestion block to skills/_journal.md. The human creator will decide.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 3d ago Changed · +18 lines 4ea02367a07a
- 5d ago Changed · +3 lines 36d76bc673e4
- 1mo ago First seen · 487 lines · 21 tokens per session scan A c4aa1f6099bb
skill-evolve is a skill published in the GitHub repository yologdev/yoyo-evolve (1,915 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 8,280 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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