bisimulation-game

bisimulation-game is a skill for Claude Code, Codex from plurigrid/asi. It costs 28 tokens per session (1,785 once invoked), scanned A, original, MIT.

A game-based framework for checking whether multiple AI agents behave equivalently under observation. One side tries to find a difference while the other responds with matching transitions.

In plain words
What is it for?
Use it to examine agent equivalence, resilient skill distribution, version-aware synchronisation, and state-transition consistency.
Why use it?
It provides a structured way to test whether agents remain synchronised and equivalent as their states change. This is useful when skills or behaviours are distributed across agents.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also reads ~/.codex or $CODEX_HOME. Also seen: reads .claude/ paths; mentions Codex.

Part of the topos-skills plugin — 29 skills shipped together

Good fit Use it to examine agent equivalence, resilient skill distribution, version-aware synchronisation, and…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/plurigrid/asi/bisimulation-game
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.

Any agent
npx skills add plurigrid/asi --skill bisimulation-game
Clone the repo
git clone --depth 1 https://github.com/plurigrid/asi

Made for: Claude Code, Codex.

Or install topos-skills, the plugin that ships this one along with the rest of its 29 skills.

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 bisimulation-game

README.md
[![agentmods](https://agentmods.dev/badge/skills/plurigrid/asi/bisimulation-game.svg)](https://agentmods.dev/skills/plurigrid/asi/bisimulation-game)
Your own site
<a href="https://agentmods.dev/skills/plurigrid/asi/bisimulation-game"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/bisimulation-game.svg" alt="Measured on agentmods" height="20"></a>
Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,785 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 $0.00028 $0.01785
Opus 5 $0.00014 $0.00892
Sonnet 5 $0.00006 $0.00357
Haiku 4.5 $0.00003 $0.00178

Measured 5d ago against content hash deac1b2bd30c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

bisimulation-game 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 5d 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.

ies/music-topos/.claude-marketplaces/topos-skills/plugins/topos-skills/skills/bisimulation-game/SKILL.md · 254 lines

How it starts

The opening of the file, as written. The whole thing — 254 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Bisimulation Game Skill

"Two systems are bisimilar if they cannot be distinguished by any observation."

Overview

The bisimulation game provides a framework for:

  1. Resilient skill dispersal across multiple AI agents
  2. GF(3) conservation during state transitions
  3. Observational bridge types for version-aware synchronization
  4. Self-rewriting capabilities via MCP Tasks protocol

Game Rules

Players

Player Role Trit Color
Attacker Tries to distinguish systems -1 Blue
Defender Maintains equivalence +1 Red
Arbiter Verifies conservation 0 Green

Moves

┌─────────────────────────────────────────────────────────────┐
│  Round n:                                                   │
│                                                             │
│  1. Attacker chooses: system S₁ or S₂                       │
│  2. Attacker makes: transition s₁ →ᵃ s₁'                    │
│  3. Defender responds: matching transition s₂ →ᵃ s₂'        │
│  4. Arbiter verifies: GF(3) conservation                    │
│                                                             │
│  If Defender cannot respond → Attacker wins (distinguishable)│
│  If game continues forever → Defender wins (bisimilar)      │
└─────────────────────────────────────────────────────────────┘

Implementation

Hy (DiscoHy) Implementation

;;; bisimulation_game.hy

(import [splitmix_ternary [SplitMixTernary]])

(defclass BisimulationGame []
  (defn __init__ [self system1 system2 seed]
    (setv self.s1 system1
          self.s2 system2
          self.rng (SplitMixTernary seed)
          self.history []))
  
  (defn attacker-move [self choice transition]
    "Attacker chooses system and transition."
    (setv trit (self.rng.next-ternary))
    (.append self.history {:role "attacker" 
                           :choice choice 
                           :transition transition
                           :trit trit})
    trit)
  
  (defn defender-respond [self matching-transition]
    "Defender provides matching transition."
    (setv trit (self.rng.next-ternary))
    (.append self.history {:role "defender"
                           :response matching-transition
                           :trit trit})
    trit)
  
  (defn arbiter-verify [self]
    "Arbiter checks GF(3) conservation."
    (setv recent-trits (lfor m (cut self.history -3 None) (get m "trit")))
    (setv conserved (= (% (sum recent-trits) 3) 0))
    (.append self.history {:role "arbiter" :conserved conserved :trit 0})
    conserved))

Read the full file on GitHub · 254 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. 5d ago First seen · 254 lines · 28 tokens per session scan A deac1b2bd30c

Subscribe to this mod's changes

bisimulation-game is a skill published in the GitHub repository plurigrid/asi (62 stars, last pushed 1mo ago), licensed MIT. It adds 28 tokens to every session and 1,785 once invoked, about $0.0001 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 2026-09-01.

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