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 axiomantic/spellbook --skill devils-advocategit clone --depth 1 https://github.com/axiomantic/spellbookWrote 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/axiomantic/spellbook/devils-advocate)<a href="https://agentmods.dev/skills/axiomantic/spellbook/devils-advocate"><img src="https://agentmods.dev/badge/skills/axiomantic/spellbook/devils-advocate/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/axiomantic/spellbook/devils-advocate"><img src="https://agentmods.dev/badge/skills/axiomantic/spellbook/devils-advocate.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00097 | $0.02040 |
| Opus 5.5 | $0.00039 | $0.00816 |
| Sonnet 5.5 | $0.00019 | $0.00408 |
| Haiku 4.5 | $0.00010 | $0.00204 |
Grade A, and why
devils-advocate 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.
How it starts
The opening of the file, as written. The whole thing — 212 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Evidence Hierarchy Reference
This skill follows the shared evidence hierarchy defined in skills/shared-references/evidence-hierarchy.md. Challenges must cite evidence tiers. An assumption flagged as UNVALIDATED must have attempted at least Medium depth verification per the Depth Escalation Protocol.
If a finding is UNVALIDATED or IMPLICIT at shallow depth, it MUST be escalated to Medium depth before inclusion in the report.
Invariant Principles
- Untested assumptions become production bugs. Every claim needs evidence or explicit "unvalidated" flag.
- Vague scope enables scope creep. Boundaries must be testable, not interpretive.
- Optimistic architecture fails at scale. Every design decision needs 10x/failure/deprecation analysis.
- Undocumented failure modes become incidents. Every integration needs explicit failure handling.
- Unmeasured success is unfalsifiable. Metrics require numbers, baselines, percentiles.
Applicability
| Use | Skip (Why) |
|---|---|
| Understanding/design doc complete | Active user discovery (no stable artifact to challenge) |
| "Challenge this" request | Code review (use code-reviewer - different scope) |
| Before architectural decision | Implementation validation (use fact-checking) |
Inputs
| Input | Required | Description |
|---|---|---|
document_path |
Yes | Path to understanding or design document to review |
focus_areas |
No | Specific areas to prioritize (e.g., "security", "scalability") |
known_constraints |
No | Constraints already accepted (skip challenging these) |
Outputs
| Output | Type | Description |
|---|---|---|
review_document |
Inline | Structured review following Output Format template |
issue_count |
Inline | Summary counts: critical, major, minor |
readiness_verdict |
Inline | Verdict per table below |
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 · 212 lines · 97 tokens per session scan A 9cc1de4225f5
devils-advocate is a skill published in the GitHub repository axiomantic/spellbook (10 stars, last pushed 2d ago), licensed MIT. It adds 97 tokens to every session and 2,040 once invoked, about $0.0004 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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