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 a-tokyo/agent-skills --skill premortemgit clone --depth 1 https://github.com/a-tokyo/agent-skillsWrote 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/a-tokyo/agent-skills/premortem)<a href="https://agentmods.dev/skills/a-tokyo/agent-skills/premortem"><img src="https://agentmods.dev/badge/skills/a-tokyo/agent-skills/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/a-tokyo/agent-skills/premortem"><img src="https://agentmods.dev/badge/skills/a-tokyo/agent-skills/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 | $0.00014 | $0.02961 |
| Opus 5.5 | $0.00006 | $0.01184 |
| Sonnet 5.5 | $0.00003 | $0.00592 |
| Haiku 4.5 | $0.00001 | $0.00296 |
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 1mo 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 — 452 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Pre-Mortem
Identify failure modes before they occur by systematically questioning plans, designs, and implementations. Based on Gary Klein's technique, popularized by Shreyas Doshi (Stripe).
Usage
/premortem # Auto-detect context, choose depth
/premortem quick # Force quick analysis (plans, PRs)
/premortem deep # Force deep analysis (before implementation)
/premortem <file> # Analyze specific plan or code
Core Concept
"Imagine it's 3 months from now and this project has failed spectacularly. Why did it fail?"
Risk Categories (Shreyas Framework)
| Category | Symbol | Meaning |
|---|---|---|
| Tiger | [TIGER] |
Clear threat that will hurt us if not addressed |
| Paper Tiger | [PAPER] |
Looks threatening but probably fine |
| Elephant | [ELEPHANT] |
Thing nobody wants to talk about |
CRITICAL: Verify Before Flagging
Do NOT flag risks based on pattern-matching alone. Every potential tiger MUST go through verification.
The False Positive Problem
Common mistakes that create false tigers:
- Seeing a hardcoded path without checking for
if exists():fallback - Finding missing feature X without asking "is X in scope?"
- Flagging code at line N without reading lines N±20 for context
- Assuming error case isn't handled without tracing the code
Verification Checklist (REQUIRED)
Before flagging ANY tiger, verify:
potential_finding:
what: "Hardcoded path at line 42"
verification:
context_read: true # Did I read ±20 lines around the finding?
fallback_check: true # Is there try/except, if exists(), or else branch?
scope_check: true # Is this even in scope for this code?
dev_only_check: true # Is this in __main__, tests/, or dev-only code?
result: tiger | paper_tiger | false_alarm
If ANY verification check is "no" or "unknown", DO NOT flag as tiger.
Required Evidence Format
Every tiger MUST include:
tiger:
risk: "<description>"
location: "file.py:42"
severity: high|medium
# REQUIRED - what mitigation was checked and NOT found:
mitigation_checked: "No exists() check, no try/except, no fallback branch"
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.
- 1mo ago First seen · 452 lines · 14 tokens per session scan A ee0f02aad104
premortem is a skill published in the GitHub repository a-tokyo/agent-skills (17 stars, last pushed 2d ago), licensed MIT. It adds 14 tokens to every session and 2,961 once invoked, about $0.0001 per session on Opus 5.5. 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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