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.
npx agentmods add skills/rileyhilliard/claude-essentials/post-mortemnpx skills add rileyhilliard/claude-essentials --skill post-mortemgit clone --depth 1 https://github.com/rileyhilliard/claude-essentialsWrote 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.
[](https://agentmods.dev/skills/rileyhilliard/claude-essentials/post-mortem)<a href="https://agentmods.dev/skills/rileyhilliard/claude-essentials/post-mortem"><img src="https://agentmods.dev/badge/skills/rileyhilliard/claude-essentials/post-mortem.svg" alt="Measured on agentmods" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00045 | $0.01164 |
| Opus 5 | $0.00023 | $0.00582 |
| Sonnet 5 | $0.00009 | $0.00233 |
| Haiku 4.5 | $0.00005 | $0.00116 |
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 5d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- post-mortem — 95% identical, 8 lines differ
How it starts
The opening of the file, as written. The whole thing — 118 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.
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.
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.
- 5d ago First seen · 118 lines · 45 tokens per session scan A 477bd205cfae
post-mortem is a skill published in the GitHub repository rileyhilliard/claude-essentials (128 stars, last pushed 17d ago), licensed MIT. It adds 45 tokens to every session and 1,164 once invoked, about $0.0002 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 2026-08-30.
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