post-mortem

post-mortem is a skill for Claude Code, Codex from rileyhilliard/agentrc. It costs 45 tokens per session (1,115 once invoked), scanned A, a copy of post-mortem, MIT.

A review of a finished coding session or task to find practical ways to improve future work. It examines problems such as confusing architecture, missing documentation, process mistakes, and developer-experience friction.

In plain words
What is it for?
Use it after a substantial task, a difficult session, a bug fix, or the discovery of a new development pattern.
Why use it?
It turns problems from a completed task into specific improvements instead of letting the same issues recur. It can reveal unclear instructions, weak processes, or patterns worth documenting.

Skill for Claude CodeCodex

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/rileyhilliard/agentrc/post-mortem
Any agent
npx skills add rileyhilliard/agentrc --skill post-mortem
Clone the repo
git clone --depth 1 https://github.com/rileyhilliard/agentrc

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 post-mortem

README.md
[![agentmods](https://agentmods.dev/badge/skills/rileyhilliard/agentrc/post-mortem.svg)](https://agentmods.dev/skills/rileyhilliard/agentrc/post-mortem)
Your own site
<a href="https://agentmods.dev/skills/rileyhilliard/agentrc/post-mortem"><img src="https://agentmods.dev/badge/skills/rileyhilliard/agentrc/post-mortem.svg" alt="Measured on agentmods" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,115 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 95% copy Near-identical to another mod 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 $0.00045 $0.01115
Opus 5 $0.00023 $0.00558
Sonnet 5 $0.00009 $0.00223
Haiku 4.5 $0.00005 $0.00112

Measured 3d ago against content hash 008e759681d6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

post-mortem 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.

Origin

This is a copy

95% identical to post-mortem — 8 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agentrc/skills/post-mortem/SKILL.md · 116 lines

How it starts

The opening of the file, as written. The whole thing — 116 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Post-Mortem

Review a completed session or task to assess how it went and extract improvements. This covers both "how did we do" evaluation and "what can we learn" investigation.

When to Use

After completing any non-trivial task or session. The goal is continuous improvement:

  • Routine review: How smooth was execution? Where did friction occur?
  • Problem sessions: Things took longer than expected, multiple corrections needed
  • Bug fixes: What caused it and what would prevent it next time?
  • New patterns: Something worked well that should be codified

Investigation Types

Load the relevant reference based on what you're investigating:

Situation Load File
Agent hit friction during execution (wrong files, bad assumptions, unclear conventions) DX Friction references/dx-friction.md
Documentation (READMEs, comments, API docs) was wrong, incomplete, or misleading Documentation Gaps references/documentation-gaps.md
Code was hard to understand or things were in unexpected places Architecture Clarity references/architecture-clarity.md
A bug was fixed but the root cause suggests a process gap Bug Prevention references/bug-prevention.md
Code works but diverges from best practices, idioms, or established conventions Anti-Patterns references/anti-patterns.md
Skills, hooks, commands, agents, or .claude/ configs need updating Tooling Improvements references/tooling-improvements.md

Load multiple references when the session spans investigation types.

Core Process

Every post-mortem follows four steps regardless of investigation type.

1. Reconstruct What Happened

Walk through the session timeline. For each significant step, note:

  • What was attempted
  • What actually happened
  • Where corrections were needed and why
  • What went smoothly (worth noting what worked, not just what didn't)

Don't editorialize yet. Just document the sequence.

Read the full file on GitHub · 116 lines

Files

What ships with it

6 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. 3d ago First seen · 116 lines · 45 tokens per session scan A 008e759681d6

Subscribe to this mod's changes

post-mortem is a skill published in the GitHub repository rileyhilliard/agentrc (3 stars, last pushed 6mo ago), licensed MIT. It adds 45 tokens to every session and 1,115 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to post-mortem, differing in 8 lines, and is treated as a copy.

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