learn

learn is a skill for Claude Code, Codex from mehrad-dm/mastermind. It costs 65 tokens per session (653 once invoked), scanned A, original, MIT.

A process for recording corrections, useful review findings, updated standards, or lessons from moving to a new technology area in a persistent knowledge base.

In plain words
What is it for?
Use it to capture a lesson, refresh standards, or set up knowledge for a new domain or technology stack.
Why use it?
It helps the agent retain important lessons and avoid repeating known mistakes after the current task.

Skill for Claude CodeCodex

Part of the mastermind plugin — 23 skills, 4 agents, 1 hook shipped together

Install

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.

agentmods
npx agentmods add skills/mehrad-dm/mastermind/learn
Any agent
npx skills add mehrad-dm/mastermind --skill learn
Clone the repo
git clone --depth 1 https://github.com/mehrad-dm/mastermind

Made for: Claude Code, Codex.

Or install mastermind, the plugin that ships this one along with the rest of its 23 skills, 4 agents, 1 hook.

Wrote 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.

agentmods badge for learn

README.md
[![agentmods](https://agentmods.dev/badge/skills/mehrad-dm/mastermind/learn.svg)](https://agentmods.dev/skills/mehrad-dm/mastermind/learn)
Your own site
<a href="https://agentmods.dev/skills/mehrad-dm/mastermind/learn"><img src="https://agentmods.dev/badge/skills/mehrad-dm/mastermind/learn.svg" alt="Measured on agentmods" height="20"></a>
Per session 65 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 653 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00065 $0.00653
Opus 5 $0.00032 $0.00327
Sonnet 5 $0.00013 $0.00131
Haiku 4.5 $0.00006 $0.00065

Measured 4d ago against content hash 45adb2192fa8, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

learn 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.

skills/learn/SKILL.md · 47 lines

How it starts

The opening of the file, as written. The whole thing — 47 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MasterMind: Learn

The invokable form of ~/.mastermind/engineering/core/agent-loop.md → "Learn the stack before you build." Topic/task: $ARGUMENTS. Goal: reach genuine, current understanding: enough to build to standard: fast, and cheap on context.

1. Detect what's actually used

Read package.json/lockfile, configs, and representative source to see the exact stack (framework + versions, styling, state, data, test runner) and the team's conventions. Installed versions matter, APIs drift, so learn the version that's actually here.

2. Map the skill-tree

Use the relevant role/topic map on the website roadmap.sh as the checklist of what matters and to spot your gaps. Learn just the branch the task touches; the rest of the tree waits.

3. Learn to current standards

Read the primary docs for the specific APIs the task needs (verify against the installed version) and skim one battle-tested example (the field's curriculum.md lists them). Prefer primary sources; read them fresh, since memory goes stale (the field's learning-sources.md).

4. Ground it in this codebase

Grep for how the pattern is already used here and match it. Consistency beats novelty.

5. Challenge your assumptions before you build

The costly bugs come from unchecked assumptions. Before committing code:

  • List what you believe about the APIs you'll use (behavior, signatures, return values, limits, versions, edge cases), specifically ("getFile streams any size", true?).
  • Answer from the source yourself first: verify each against the docs/types/actual source (for the installed version). Confirm ✓, correct ✗, or mark unknown ❓. Anything the code/docs answer, you answer.
  • For each remaining unknown, propose a resolution: a bare flag is half the job. State a best guess + confidence ("probably streams; ~70%") so a human can confirm or correct, not author it. Serve interdependent unknowns one at a time. Anything still unconfirmed becomes an explicit risk or a tiny prototype, never a silent guess. No load-bearing assumption ships unverified.

Read the full file on GitHub · 47 lines

Files

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.

Changes

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.

  1. 4d ago First seen · 47 lines · 0 tokens per session scan A 45adb2192fa8

Subscribe to this mod's changes

learn is a skill published in the GitHub repository mehrad-dm/mastermind (24 stars, last pushed 4d ago), licensed MIT. It adds 65 tokens to every session and 653 once invoked, about $0.0003 per session on Opus 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.