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 skills add PabloNAX/premortem-skill --skill premortemgit clone --depth 1 https://github.com/PabloNAX/premortem-skillWrote 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/pablonax/premortem-skill/premortem)<a href="https://agentmods.dev/skills/pablonax/premortem-skill/premortem"><img src="https://agentmods.dev/badge/skills/pablonax/premortem-skill/premortem/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.
<a href="https://agentmods.dev/skills/pablonax/premortem-skill/premortem"><img src="https://agentmods.dev/badge/skills/pablonax/premortem-skill/premortem.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00183 | $0.04019 |
| Opus 5 | $0.00092 | $0.02010 |
| Sonnet 5 | $0.00037 | $0.00804 |
| Haiku 4.5 | $0.00018 | $0.00402 |
Grade A, and why
premortem 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 9d 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.
This is a copy
100% identical to premortem — 0 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.
How it starts
The opening of the file, as written. The whole thing — 260 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Premortem
A premortem is the opposite of a postmortem. Instead of figuring out what went wrong after something fails, you imagine it already failed and figure out why before you start.
The method comes from psychologist Gary Klein. He published it in Harvard Business Review. Daniel Kahneman (the Nobel Prize-winning psychologist behind "Thinking, Fast and Slow") called it his single most valuable decision-making technique. Google, Goldman Sachs, and Procter & Gamble all use it before major decisions.
The core insight: when you ask people "what could go wrong?" they give you cautious, hedged answers. When you say "this already failed, tell me why," their brains switch into narrative mode and generate way more specific, creative, honest reasons. Researchers at Wharton and Cornell called this "prospective hindsight" and found it significantly increases the ability to identify causes of future outcomes.
The reason this matters for AI-assisted decisions: Claude defaults to agreeable, optimistic responses. If you ask "is this a good plan?" it will find reasons to say yes. The premortem breaks this pattern by forcing the frame into "this is dead, explain how it died." Claude stops looking for reasons your plan will work and starts explaining how it fell apart.
when to run a premortem
Good premortem targets:
- A product or feature you're about to build
- A launch plan with money or reputation on the line
- A pricing change or business model shift
- A hire you're about to make
- A strategy or positioning pivot
- A partnership or deal you're evaluating
- Any commitment where the cost of being wrong is high
Bad premortem targets:
- Vague ideas with no concrete plan yet (help them plan first, then premortem)
- Questions with one right answer (just answer them)
- Requests for creative feedback on a draft (that's editing, not a premortem)
- Decisions that are already made and irreversible (a premortem is only useful when you can still change course)
context gathering (the minimum bar)
What ships with it
1 file 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.
- 9d ago First seen · 260 lines · 183 tokens per session scan A 7bf67cd9c2a9
premortem is a skill published in the GitHub repository PabloNAX/premortem-skill (32 stars, last pushed 2mo ago), licensed MIT. It adds 183 tokens to every session and 4,019 once invoked, about $0.0009 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to premortem, differing in 0 lines, and is treated as a copy.
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