retro

retro is a skill for Claude Code from krzysztofsurdy/code-virtuoso. It costs 69 tokens per session (1,339 once invoked), scanned A, original, MIT.

A review process for a coding-agent session that identifies wasted steps, repeated mistakes, missing checks and ignored rules. It turns those findings into lasting fixes such as lint rules, hooks or continuous-integration checks.

In plain words
What is it for?
Use it after an agent coding session to examine retries, reverted edits, failed checks and duplicated work, then improve the agent's working environment.
Why use it?
It prevents the same correction from being repeated in later sessions. The focus is on evidence from the conversation, Git changes and command results rather than a general feeling that the session went badly.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter.

Part of the playbooks-virtuoso plugin — 12 skills shipped together

Good fit Use it after an agent coding session to examine retries, reverted edits, failed checks and duplicated work, then improve the agent's working environment.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/krzysztofsurdy/code-virtuoso/retro
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 krzysztofsurdy/code-virtuoso --skill retro
Clone the repo
git clone --depth 1 https://github.com/krzysztofsurdy/code-virtuoso

Made for: Claude Code.

Or install playbooks-virtuoso, the plugin that ships this one along with the rest of its 12 skills.

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 retro

README.md
[![agentmods](https://agentmods.dev/badge/skills/krzysztofsurdy/code-virtuoso/retro/github.svg)](https://agentmods.dev/skills/krzysztofsurdy/code-virtuoso/retro)
Your own site
<a href="https://agentmods.dev/skills/krzysztofsurdy/code-virtuoso/retro"><img src="https://agentmods.dev/badge/skills/krzysztofsurdy/code-virtuoso/retro/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 retro

Your own site · 80×15
<a href="https://agentmods.dev/skills/krzysztofsurdy/code-virtuoso/retro"><img src="https://agentmods.dev/badge/skills/krzysztofsurdy/code-virtuoso/retro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,339 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 $0.00069 $0.01339
Opus 5.5 $0.00028 $0.00536
Sonnet 5.5 $0.00014 $0.00268
Haiku 4.5 $0.00007 $0.00134

Measured today against content hash dc86754df4a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

retro 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 today.

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/playbooks/retro/SKILL.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Retro

An agent session ends and the lessons go with it. The same correction gets typed again next week, and the usual fix, one more line in a rules file, is the weakest one: the file grows, the agent skips lines, and the mistake returns. This playbook looks back at a session, finds where it lost time or quality, and picks for each finding the cheapest fix that lasts. Default to a deterministic check. Write a prose rule only when no check can catch the problem.

This is for the agent's working environment, not a team ceremony. For a Scrum sprint retrospective use the scrum skill.

A repeated mistake with no guardrail is itself a finding. Fixing the code once does not count as a fix.

Procedure

  1. Gather the friction. Work from evidence, not a feeling that it went badly:

    • The current conversation: corrections the user made, errors, retries, dead ends.
    • git log and git diff for the session: reverted edits, fix-up commits, files touched twice.
    • Command output: failing checks, slow steps, commands that were run and changed nothing.
    • Progress or handoff notes if they exist.

    If the session is not in front of you, ask the user for the three or four moments that hurt most. Do not invent findings. Seven real ones beat twenty guesses. Scan the categories in categories so nothing obvious is missed.

  2. Write each finding as one fact. What happened, how many times, what it cost (turns, retries, a wrong commit). "Agent imported from the old module path in 3 files, user corrected it twice" is a finding. "Agent was sloppy" is not.

  3. Classify the fix. Take the first row that fits.

    The problem is Fix Lands in
    A fixed pattern a program can recognise: banned API, import shape, file location, naming, formatting, a missing step before commit Deterministic check Linter or static-analysis rule, formatter config, pre-commit hook, agent hook, CI job, or a test
    A call that needs taste or context a program cannot judge One short rule The project's rules file, or a path-scoped rule if it applies to one area
    The agent could not find something, or loaded too much Navigation or context fix A pointer in the rules file, a doc moved or renamed, an instruction file trimmed or split
    A step that changed nothing, or a tool call repeated Remove or cache it Drop the step from the workflow, script, or skill, or record the answer where the agent finds it

Read the full file on GitHub · 65 lines

Files

What ships with it

2 files 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. today First seen · 65 lines · 69 tokens per session scan A dc86754df4a4

Subscribe to this mod's changes

retro is a skill published in the GitHub repository krzysztofsurdy/code-virtuoso (36 stars, last pushed yesterday), licensed MIT. It adds 69 tokens to every session and 1,339 once invoked, about $0.0003 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 2026-10-24.

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