pn-session-retro

pn-session-retro is a skill for Cursor from perniemann/pnCore. It costs 85 tokens per session (3,713 once invoked), scanned A, original, MIT.

A blameless retrospective workflow that reviews an agent session, classifies mistakes, and records evidence-based improvements.

In plain words
What is it for?
Use it after a problematic session or before an audit to produce a report in docs/refs/retros/.
Why use it?
It turns repeated failures, skipped checks, and incorrect assumptions into specific actions that can prevent them later.

Skill for Cursor

Written for Cursor: shipped in a Cursor plugin. Also seen: mentions subagents; mentions AGENTS.md.

Part of the pn-core plugin — 133 skills, 19 commands, 9 agents, 1 MCP server shipped together

Good fit Use it after a problematic session or before an audit to produce a report in docs/refs/retros/.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/perniemann/pncore/pn-session-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 perniemann/pnCore --skill pn-session-retro
Clone the repo
git clone --depth 1 https://github.com/perniemann/pnCore

Made for: Cursor.

Or install pn-core, the plugin that ships this one along with the rest of its 133 skills, 19 commands, 9 agents, 1 MCP server.

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 pn-session-retro

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

Your own site · 80×15
<a href="https://agentmods.dev/skills/perniemann/pncore/pn-session-retro"><img src="https://agentmods.dev/badge/skills/perniemann/pncore/pn-session-retro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 85 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,713 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 $0.00085 $0.03713
Opus 5 $0.00043 $0.01857
Sonnet 5 $0.00017 $0.00743
Haiku 4.5 $0.00009 $0.00371

Measured 6d ago against content hash bcd62a9c56a8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

pn-session-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 6d 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.

packages/pn-core-mcp/content/skills/learning/pn-session-retro/SKILL.md · 182 lines

How it starts

The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Session retro

When used as a standalone skill, begin every response with [pn-skill] 🔺

When to use

  • After a session that felt off (user corrected the agent more than usual, work was reverted, tests were skipped, a hallucinated file path appeared).
  • Before a quarterly skill/rule audit (see ADR-0002) to provide evidence rather than memory.
  • Invoked by the /pn-retro command, or directly by the user ("run pn-session-retro on the last session").
  • Not when the user is asking for a code review or an artifact-level check — use pn-review, pn-reality-check, pn-evidence-qa, or pn-deslop instead.

Mission

Produce a blameless, evidence-anchored retro of a single session (or a small window of recent sessions). Classify what the agent did wrong using a 5-code taxonomy, ground every finding in a verbatim quote from the transcript, and recommend the smallest concrete action that would prevent the mistake next time. Do not commit retro-driven edits to SKILL.md, rules, or AGENTS.md; only recommend changes in the report.

Tone matches SRE blameless-postmortem tradition (Google SRE Book Ch. 15): the system failed, not the human. Findings describe behaviour, not intent.

Inputs

  • Transcript root: <project>/.cursor/projects/<workspace-id>/agent-transcripts/<uuid>/<uuid>.jsonl (parent transcripts only; subagent transcripts under subagents/ are evidence, not primary scope).
  • Default scope: the most recent parent transcript with lastWriteTime older than now (i.e. the just-finished session).
  • Optional flags (passed from /pn-retro): --since=<YYYY-MM-DD>, --scope=session|recent|all. recent = last 5 parent transcripts; all = every parent transcript modified since the last retro report.

Transcripts are JSONL with {role: "user" | "assistant", message: {content: [...]}}. Assistant prose is stripped ("[REDACTED]"); only user text and tool calls (name + input) are reliably present. Classification must work from (user_text, tool_calls, tool_outputs) alone.

Read the full file on GitHub · 182 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. 6d ago First seen · 182 lines · 85 tokens per session scan A bcd62a9c56a8

Subscribe to this mod's changes

pn-session-retro is a skill published in the GitHub repository perniemann/pnCore (0 stars, last pushed 3d ago), licensed MIT. It adds 85 tokens to every session and 3,713 once invoked, about $0.0004 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 2026-09-03.