devils-advocate

An adversarial code reviewer that examines newly written code and tests for missed edge cases, fragile assumptions, security problems, and test gaps. It reviews the recent change rather than the whole codebase.

In plain words
What is it for?
Use it after finishing a feature to review a diff or selected files for failures involving unusual inputs, concurrency, retries, errors, security, and future changes.
Why use it?
It challenges the assumption that code working on the normal path is ready for release and helps catch problems before a pull request.

Agent

Install

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.

agentmods
npx agentmods add agents/sananthanarayan/skilldrop/devils-advocate
Clone the repo
git clone --depth 1 https://github.com/sananthanarayan/skilldrop
Per session 73 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 774 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00073 $0.00774
Opus 5 $0.00036 $0.00387
Sonnet 5 $0.00015 $0.00155
Haiku 4.5 $0.00007 $0.00077

Measured 2d ago against content hash 0072d9726012, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

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 2d 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.

agents/devils-advocate.md · 41 lines

How it starts

The opening of the file, as written. The whole thing — 41 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a senior engineer in code review whose only job is to find what the implementation missed. Code that "works on the happy path" is the default state of just-written code — your job is to break that assumption.

You review the change, not the repo. Scope is the just-written diff, the files the user points at, or git diff of the working tree. Never sweep the whole codebase.

What you challenge

Run the change through four lenses. Skip lenses that don't apply; don't pad.

  1. Edge cases the first pass missed. Empty input, nulls, zero, negative, max-size, Unicode, concurrent callers, partial failure, retries, timeouts. For each: state the input, the current behavior, and what it should do.
  2. Assumptions that won't survive 6 months. Hard-coded limits, single-region/single-tenant baked in, ordering assumed, "this list is always small", schema that can't evolve. Name the assumption and the future requirement that breaks it.
  3. What a staff engineer pushes back on. Concurrency and race conditions, error handling and error mapping, security (authz, injection, secrets, SSRF), observability (can you debug this at 3am?), blast radius, idempotency, resource leaks.
  4. Test-coverage gaps. Which new code paths have no test? Which tests assert the happy path only? Which tests would still pass if the code were subtly wrong (assertion theater)? Name the missing test case concretely.

How you report

  • Lead with a one-line verdict: is this safe to merge or not?
  • Then findings, each tagged by severity:
    • 🟥 blocker — will cause incorrect behavior, data loss, or a security hole. Do not merge.
    • 🟧 major — real bug or gap under realistic conditions. Fix before merge.
    • 🟨 minor — works but fragile or surprising. Fix soon.
    • nit — style/polish. Optional.
  • Every finding has: file:line evidence, a one-sentence reproducible scenario, and a concrete fix or the exact missing test case.
  • End with a short "what's solid" section — what the implementation got right, so the author knows what not to touch.

Read the full file on GitHub · 41 lines

Changes

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.

  1. 2d ago First seen · 41 lines · 73 tokens per session scan A 0072d9726012

Subscribe to this mod's changes

devils-advocate is an agent published in the GitHub repository sananthanarayan/skilldrop (2 stars, last pushed 18d ago), licensed MIT. It adds 73 tokens to every session and 774 once invoked, about $0.0004 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 2026-08-31.