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 agentmods add skills/agenttoolkit/altk-evolve/synthesize-skillnpx skills add AgentToolkit/altk-evolve --skill synthesize-skillgit clone --depth 1 https://github.com/AgentToolkit/altk-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/agenttoolkit/altk-evolve/synthesize-skill)<a href="https://agentmods.dev/skills/agenttoolkit/altk-evolve/synthesize-skill"><img src="https://agentmods.dev/badge/skills/agenttoolkit/altk-evolve/synthesize-skill.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00055 | $0.02102 |
| Opus 5 | $0.00028 | $0.01051 |
| Sonnet 5 | $0.00011 | $0.00420 |
| Haiku 4.5 | $0.00006 | $0.00210 |
Grade A, and why
synthesize-skill 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 4d 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.
This is a copy
94% identical to evolve-lite:synthesize-skill — 17 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 154 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill Synthesizer
Overview
This skill reads a saved trajectory and produces a reusable agent skill — a SKILL.md plus any supporting scripts — that captures the successful workflow the session discovered. The output goes to .evolve/skills/<skill-name>/ (canonical, evolve-managed) and to .claude/skills/<skill-name>/ (so Claude Code's skills loader picks it up automatically). Future sessions on the same project can then invoke the skill directly instead of re-deriving the workflow.
This is the executable counterpart to the learn skill's free-text guidelines: learn writes Markdown the next agent has to read and decide what to do; synthesize-skill writes a skill the next agent can simply call.
When To Use
Use this skill when a trajectory captured:
- A non-trivial workflow that succeeded after trial-and-error (the eventual happy path is worth promoting from free-text advice to an invocable artifact).
- A reusable script or command sequence the model wrote during the session — particularly one the agent had to reconstruct over multiple attempts.
- An environment-specific workaround (a missing system tool, a permissions wrinkle, a fallback pipeline) that future sessions in the same project will hit.
Skip this skill — and let learn cover the case with a guideline alone — when:
- The successful path was a single trivial command.
- The workflow embeds secrets, tokens, or one-off user inputs that can't be safely generalized.
- A skill with the same trigger already exists in
.evolve/skills/(uselearn's guideline path to refine the existing skill instead of creating a duplicate).
Workflow
Step 0: Locate the Trajectory
This skill runs in a forked context. You cannot see the parent conversation directly — read the trajectory the parent passed in via args or via the Run /evolve-lite:synthesize-skill on <path> instruction.
The trajectory path is either:
- supplied directly as
argsto the skill invocation, or - stated in the parent's invocation message as
The saved trajectory path is: <path>— take everything after the colon, strip surrounding whitespace and quotes.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 4d ago First seen · 154 lines · 55 tokens per session scan A 3c7393a138cf
synthesize-skill is a skill published in the GitHub repository AgentToolkit/altk-evolve (105 stars, last pushed yesterday), licensed Apache-2.0. It adds 55 tokens to every session and 2,102 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to evolve-lite:synthesize-skill, differing in 17 lines, and is treated as a copy.
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