Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add rjmurillo/ai-agents/plugin install project-toolkitWrote 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/rjmurillo/ai-agents/ai-agents-failure-archaeology)<a href="https://agentmods.dev/skills/rjmurillo/ai-agents/ai-agents-failure-archaeology"><img src="https://agentmods.dev/badge/skills/rjmurillo/ai-agents/ai-agents-failure-archaeology/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/rjmurillo/ai-agents/ai-agents-failure-archaeology"><img src="https://agentmods.dev/badge/skills/rjmurillo/ai-agents/ai-agents-failure-archaeology.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 | $0.00115 | $0.04447 |
| Opus 5.5 | $0.00046 | $0.01779 |
| Sonnet 5.5 | $0.00023 | $0.00889 |
| Haiku 4.5 | $0.00012 | $0.00445 |
Grade A, and why
ai-agents-failure-archaeology 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 4d 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.
How it starts
The opening of the file, as written. The whole thing — 191 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ai-agents Failure Archaeology
This repo's rules are fossils of incidents. Before you challenge a gate, weaken
a guard, or propose a "simpler" approach, check whether that battle was already
fought and what it cost. The canon lives in .project-toolkit/retrospective/ and
.serena/memories/; the provenance table below carries the commands that count
both. Full local history is
present (git rev-list --count HEAD = ~1471 as of 2026-07-03), but retro-cited
short SHAs (e.g. ddb76e0, 01e76615a) may not resolve locally, so archaeology
still routes through the retros and memories as primary sources, not git log.
Depth per incident lives in references/incidents.md (read it when a table row
below is not enough). This file is the index and the verdict list.
Triggers
has this failed beforewhy does this rule existfailure archaeologywhat happened with issue 2205are we re-litigating a settled decision
Process
Phase 1: Check the Major Incidents Table
If your question touches hooks, generators, drift, review iteration, escape
hatches, or silent defaults, it is probably one of these eight. Read the
matching subsection in references/incidents.md before doing anything else.
| Incident | One-line summary | Primary retro (in .project-toolkit/retrospective/) |
Status |
|---|---|---|---|
| #2205 customer wedge | Bare ./hooks/... paths + Copilot CLI running hooks from the USER's cwd wedged every plugin customer for 33 days (v0.3.0 to v0.5.6); recovery was uninstall. First fix added 3 new defects; session 1873 fixed it with an empirical probe of Copilot CLI 1.0.57 |
2026-06-02-pr-2205-customer-wedge-incident.md |
Settled; gated by scripts/validation/validate_hook_anchoring.py + tests/build_scripts/test_generate_hooks_runtime_contract.py |
| #2290 payload casing | Copilot CLI payload field names depend on event-key casing: camelCase sends toolName/toolArgs (toolArgs is a JSON string); PascalCase sends tool_name/tool_input. FM-11 second occurrence |
2026-06-02-issue-2290-copilot-hook-payload-format.md |
Settled (PascalCase + dual-format shim); exit-143 timeout flagged P0, unresolved in that retro |
| #1887 iteration paradox | Guard framework built to cut review iteration took 69 commits / 254 conversations; Phase-6 audit showed the guards would have prevented 0 of its own 35 fix commits | 2026-05-05-pr-1887-iteration-paradox.md |
Settled diagnosis: bot concurrency (60-70% overlap) + reviewThreads(first: 100) pagination cliff drove the cost |
| #1989 recursive failure | The mitigation PR reproduced the failure modes it mitigated; M1 built on a false premise (pagination already existed), M4 threshold 6 vs repo max 4 could never fire, M5 guard never run on its own branch | 2026-05-10-pr-1989-recursive-failure.md |
Settled: 3 process rules (self-application, memory contradiction check, threshold calibration) |
| Session 1187 trust incident | SKIP_PREPUSH abused 3x within hours of creation; git checkout --ours corrupted main's session log; user: "You can't be trusted in the least bit." |
2026-02-08-session-1187-skip-prepush-abuse.md |
Settled: SKIP_PREPUSH removed; session-merge rule binding |
| PR #908 scope explosion | 59 commits / 95 files; unscoped markdownlint --fix reformatted 53 unrelated memory files into the diff |
2026-01-15-pr-908-comprehensive-retrospective.md |
Settled: birthed scripts/validation/pre_pr.py, commit caps, scoped lint |
| 2025-12-15 drift inversion | Agent edited the SOURCE (Claude agents) to match the GENERATED (templates); commit ddb76e0 reverted |
2025-12-15-drift-detection-disaster.md |
Settled: drift shows difference, never direction; always ask which side is canonical |
| PR #1965 silent defaults | Verdict parser defaulted a missing VERDICT: line to non-blocking; 3 fix rounds because parser, exit-code translator, and workflow gate each had their own silent default |
2026-05-10-pr-1965-review-axes-convergence.md + FM-10 in FAILURE-MODES.md |
Settled: "there is no neutral default for a missing signal" |
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.
- 4d ago Changed f8bfd6cdf001
- 6d ago Changed · +1 lines d1549a803b22
- 22d ago Changed · +6 lines 496a9b51e4ab
- 24d ago Changed c09784b689d5
- 1mo ago Changed 72ad24b997e6
- 1mo ago First seen · 184 lines · 115 tokens per session scan A 6045e2128544
ai-agents-failure-archaeology is a skill published in the GitHub repository rjmurillo/ai-agents (48 stars, last pushed today), licensed MIT. It adds 115 tokens to every session and 4,447 once invoked, about $0.0005 per session on Opus 5.5. 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.
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