lessons-learned-log

lessons-learned-log is a skill for Claude Code, Codex from samuelgudi/iknowkungfu. It costs 65 tokens per session (1,215 once invoked), scanned A, original, MIT.

A dated list of short, practical rules learned from mistakes or non-obvious discoveries. Each entry records what to do in a similar situation next time.

In plain words
What is it for?
Recording recurring fixes, surprising findings, and patterns that future work should account for. It helps decide when to review older advice as tools and circumstances change.
Why use it?
It prevents hard-won knowledge from being forgotten and stops the same mistake from being repeated. It also keeps useful lessons separate from longer incident reports or journals.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Recording recurring fixes, surprising findings, and patterns that future work should account for. It helps decide when to review older advice as tools and circumstances change.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/samuelgudi/iknowkungfu/lessons-learned-log
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.

Any agent
npx skills add samuelgudi/iknowkungfu --skill lessons-learned-log
Clone the repo
git clone --depth 1 https://github.com/samuelgudi/iknowkungfu

Made for: Claude Code, Codex.

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 lessons-learned-log

README.md
[![agentmods](https://agentmods.dev/badge/skills/samuelgudi/iknowkungfu/lessons-learned-log/github.svg)](https://agentmods.dev/skills/samuelgudi/iknowkungfu/lessons-learned-log)
Your own site
<a href="https://agentmods.dev/skills/samuelgudi/iknowkungfu/lessons-learned-log"><img src="https://agentmods.dev/badge/skills/samuelgudi/iknowkungfu/lessons-learned-log/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.

agentmods 80×15 button for lessons-learned-log

Your own site · 80×15
<a href="https://agentmods.dev/skills/samuelgudi/iknowkungfu/lessons-learned-log"><img src="https://agentmods.dev/badge/skills/samuelgudi/iknowkungfu/lessons-learned-log.svg" alt="Reviewed on agentmods" width="80" 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 1,215 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00065 $0.01215
Opus 5 $0.00032 $0.00607
Sonnet 5 $0.00013 $0.00243
Haiku 4.5 $0.00006 $0.00121

Measured 11d ago against content hash 2cb360d02a43, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

lessons-learned-log 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 11d 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/samuelgudi/lessons-learned-log/SKILL.md · 81 lines

How it starts

The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.

lessons-learned-log

A lessons log is a growing list of short rules, each one distilled from a real mistake or a real discovery. Its purpose is narrow and specific: stop the same mistake from happening twice.

A lesson is not an incident report, a postmortem, or a journal entry. It is a single actionable rule. The report explains what happened; the lesson says what to do next time. This skill is about the second thing.

Use this skill when

  • A mistake was made that should not be repeated.
  • A non-obvious solution was found to a problem that will recur.
  • A pattern was noticed that future work in this area should account for.

If the thing you learned is obvious in hindsight to anyone, it is not a lesson — it is just knowledge. A lesson is something that was not obvious and cost something to discover.

The format

One line per lesson:

- [YYYY-MM-DD] When {situation}, {what to do or remember}. (why — what went wrong)

Three parts, all mandatory:

  • The date. Context decays. A lesson from two years ago about a tool that has since changed needs to be re-evaluated, and the date is what tells you to re-evaluate it.
  • The rule. A situation and a response. "When committing code, push immediately afterward" — not "be careful with git". A rule you cannot act on is not a rule.
  • The why. What actually went wrong. The why is what makes the rule stick — and it is what lets a future reader judge whether the rule still applies, or whether the underlying cause is gone.

Examples:

- [2026-04-01] When committing code, push immediately afterward. (lost two releases of work to disk failure because the commits were never pushed)
- [2026-03-28] When installing CUDA-build PyTorch with a package manager, install torch separately first with the explicit index URL, then the rest. (a combined install resolves every dependency against the CUDA index, which does not host the non-torch packages)
- [2026-04-04] When a templated UI silently ignores an event handler, bind it in code rather than inline in the template. (inline handlers fail silently in template-owner documents — no error, just nothing happens)

Read the full file on GitHub · 81 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. 11d ago First seen · 81 lines · 65 tokens per session scan A 2cb360d02a43

Subscribe to this mod's changes

lessons-learned-log is a skill published in the GitHub repository samuelgudi/iknowkungfu (2 stars, last pushed 1mo ago), licensed MIT. It adds 65 tokens to every session and 1,215 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 2026-08-31.

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