retro

retro is a skill for Claude Code, Codex from Tiltely/lens. It costs 60 tokens per session (757 once invoked), scanned A, original, MIT.

A retrospective workflow that reviews queued coding sessions for recurring patterns, missing questions, and weaknesses in existing lenses. A retrospective is a review after work is finished.

In plain words
What is it for?
It helps process session transcripts, suggest new lenses or lens updates, propose project-instruction changes, and save approved observations to a private record.
Why use it?
It helps turn past session experience into improvements without requiring someone to inspect every session manually. It also stops clearly when the required private memory configuration is missing.

Skill for Claude CodeCodex

Part of the lens plugin — 11 skills, 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/tiltely/lens/retro
Any agent
npx skills add Tiltely/lens --skill retro
Clone the repo
git clone --depth 1 https://github.com/Tiltely/lens

Made for: Claude Code, Codex.

Or install lens, the plugin that ships this one along with the rest of its 11 skills, 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 retro

README.md
[![agentmods](https://agentmods.dev/badge/skills/tiltely/lens/retro.svg)](https://agentmods.dev/skills/tiltely/lens/retro)
Your own site
<a href="https://agentmods.dev/skills/tiltely/lens/retro"><img src="https://agentmods.dev/badge/skills/tiltely/lens/retro.svg" alt="Measured on agentmods" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 757 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 $0.00060 $0.00757
Opus 5 $0.00030 $0.00378
Sonnet 5 $0.00012 $0.00151
Haiku 4.5 $0.00006 $0.00076

Measured 3d ago against content hash 2c7c56cf320d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, 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 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.

skills/retro/SKILL.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Lens Retro

Requires a lens config with foundry set (a Claude Code feature — the loop is not supported on Cowork; see /lens:setup). Discover the config first-readable-wins: $LENS_CONFIG~/.claude/lens.json~/lens/lens.json. If none is found: explain in one line, point to /lens:setup, stop. Never error.

Compute the pending set

  1. Read <foundry>/pending-retros.jsonl and <foundry>/processed-retros.jsonl.
  2. Pending = entries whose session_id is NOT in the processed file. (Both files are append-only. NEVER rewrite or truncate them — a SessionEnd hook may append concurrently.)
  3. Gap entries ("type":"gap") are pending until a processed marker with their date+lens+note hash appears; treat each as a one-line observation candidate.
  4. If the user passed an explicit transcript/session argument, process only that.

Process each entry (serially, v1)

For session entries, read the transcript (it is JSONL; grep/skim for the lens questions, user answers, friction moments — do not load the whole file blindly if it is huge). Ask of each:

  • What questions arose that NO current lens covers? (check core/registry.md)
  • Did a lens perform poorly — wrong tier order, dumb question, missed follow-up?
  • Did durable PROJECT facts surface that are missing from that project's CLAUDE.md? If the transcript file no longer exists: mark processed, note "transcript gone", skip.

Cross-entry synthesis

After individual passes, look across entries for repetition. A pattern seen ≥2 times is a proposal candidate:

  • New lens → name it, one-line purpose, 3 sample questions → on approval, hand to /lens:new (which writes it to your global foundry, a project .lens/, or — for maintainers — the bundled set).
  • Lens update → for a lens you created (in <foundry>/lenses/ or a project .lens/): concrete diff, apply on approval. For a bundled lens: if the session is inside the lens plugin repo (maintainer context), apply the diff there; otherwise emit it as a local file and suggest a PR to the public plugin repo.
  • CLAUDE.md update → concrete diff, addressed to the specific project's CLAUDE.md.

Read the full file on GitHub · 60 lines

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. 3d ago First seen · 60 lines · 60 tokens per session scan A 2c7c56cf320d

Subscribe to this mod's changes

retro is a skill published in the GitHub repository Tiltely/lens (5 stars, last pushed 25d ago), licensed MIT. It adds 60 tokens to every session and 757 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.

Related

Other skills, from other repositories

mem0-oss-to-platform

Plan and then execute a migration of a project from the mem0 open-source / self-hosted SDK (the local Memory class) to the mem0 Platform / hosted / managed SDK (the MemoryClient class). Use this whenever a developer wants to move, switch, or migrate their mem0 usage off OSS/self-hosted to the hosted API — e.g.…

mem0ai/mem0 · 273 tokens

Cortex

Operate Cortex, the LifeOS memory system — the typed Knowledge Archive (People, Companies, Ideas, Research with typed related: links) plus recall of prior work sessions, ISAs, and conversations. Search, add, harvest, develop, ingest, distill, graph-navigate, recall. USE WHEN cortex, knowledge, knowledge base, search…

danielmiessler/LifeOS · 196 tokens

auditing-subgroup-fairness

Audit an OpenMed NER or de-identification model for performance disparities across demographic subgroups (sex, age band, race/ethnicity when available) using openmed.eval.fairnessreport. Use when the user wants per-subgroup recall and leakage, wants to check whether de-identification under-protects a group, wants to…

maziyarpanahi/openmed · 148 tokens

agent-memory

../../../engineering/agent-memory/skills/agent-memory/SKILL.md.

alirezarezvani/claude-skills · 0 tokens

memory

Use when the user asks to remember, recall, forget, update, search, or inspect durable OpenSquilla memory, including profile facts in USER.md and long-term notes in MEMORY.md or memory//.md.

opensquilla/opensquilla · 44 tokens

ha-data-stores

Map of Hope Agent's local data stores and safe read-only query workflow. Use when the user asks where Hope Agent stores data, wants to inspect sessions/messages/memory/logs/background jobs/knowledge indexes/settings, asks the model to query local app data, or debugging requires checking persisted state. Trigger…

shiwenwen/hope-agent · 115 tokens