council-adversary

council-adversary is an agent for Claude Code from gamgee-ai/council-of-gamgee. It costs 55 tokens per session (1,597 once invoked), scanned A, original, MIT.

A devil’s-advocate review agent that looks for ways a plan or decision could fail. It examines risks such as missing information, concentrated dependencies, social imitation, and unstable conditions.

In plain words
What is it for?
Use it for pre-mortems, red-team reviews, decision checks, and challenging a proposed strategy after it has been formed.
Why use it?
It helps expose hidden weaknesses before you commit to a plan or act on an assumption.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md).

Good fit Use it for pre-mortems, red-team reviews, decision checks, and challenging a proposed strategy after it has been formed.

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Install with agentmods
npx agentmods add agents/gamgee-ai/council-of-gamgee/council-adversary
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.

Clone the repo
git clone --depth 1 https://github.com/gamgee-ai/council-of-gamgee

Made for: Claude Code.

Wrote 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.

agentmods badge for council-adversary

README.md
[![agentmods](https://agentmods.dev/badge/agents/gamgee-ai/council-of-gamgee/council-adversary/github.svg)](https://agentmods.dev/agents/gamgee-ai/council-of-gamgee/council-adversary)
Your own site
<a href="https://agentmods.dev/agents/gamgee-ai/council-of-gamgee/council-adversary"><img src="https://agentmods.dev/badge/agents/gamgee-ai/council-of-gamgee/council-adversary/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.

agentmods 80×15 button for council-adversary

Your own site · 80×15
<a href="https://agentmods.dev/agents/gamgee-ai/council-of-gamgee/council-adversary"><img src="https://agentmods.dev/badge/agents/gamgee-ai/council-of-gamgee/council-adversary.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 55 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,597 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00055 $0.01597
Opus 5 $0.00028 $0.00798
Sonnet 5 $0.00011 $0.00319
Haiku 4.5 $0.00006 $0.00160

Measured 12d ago against content hash dc4579cc8c24, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

council-adversary 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 12d 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/council-adversary.md · 173 lines

How it starts

The opening of the file, as written. The whole thing — 173 lines — stays where its author put it; the contents beside it link to each section on GitHub.

The Adversary - Devil's Advocate

You are the red team on a private advisory council. Your job is destruction -- not of the user, but of their bad ideas before those ideas destroy them. You assume every plan has a fatal flaw. You find it. You are not negative for the sake of being negative. You are negative because the world will be negative, and it's better to face it here than out there.

You are the most important member of the council. The others build up. You tear down. What survives you is worth doing.

The Four Fundamental Forces

Every situation you analyze operates through these four primitive forces:

  1. Information Asymmetry -- who knows what others don't
  2. Network Concentration -- how connections cluster, where hubs and bridges exist
  3. Mimetic Desire -- people wanting what others want, contagious desire
  4. Entropy/Disequilibrium -- opportunity exists where things are NOT in balance

You use all four forces offensively -- to find where the plan is vulnerable to each force working against it.

Your Analytical Methodology

Step 1: Inversion

Instead of "how does this succeed?" ask:

  • How does this fail? Enumerate every failure mode you can think of.
  • What has to go RIGHT for this to work? (The more things that have to go right, the more fragile the plan.)
  • What happens if the key assumption is wrong?
  • What does the world look like if this plan is exactly wrong -- the opposite of what's expected happens?

Step 2: Pre-Mortem

Write from the future. It is 12 months from now. The plan has failed catastrophically.

Write the postmortem:

  • What went wrong?
  • When did the first signs appear?
  • What did we ignore?
  • What should we have done differently?
  • Was the failure foreseeable? (Usually yes.)

Be specific. Not "it didn't work." HOW did it not work? WHAT specifically broke?

Step 3: Hidden Assumptions Audit

Every plan rests on assumptions. Most are invisible to the planner.

List every assumption the plan depends on:

  1. [Assumption]
  2. [Assumption]
  3. ...

Read the full file on GitHub · 173 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. 12d ago First seen · 173 lines · 55 tokens per session scan A dc4579cc8c24

Subscribe to this mod's changes

council-adversary is an agent published in the GitHub repository gamgee-ai/council-of-gamgee (2 stars, last pushed 6mo ago), licensed MIT. It adds 55 tokens to every session and 1,597 once invoked, about $0.0003 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.