open-games

open-games is a skill for Codex from plurigrid/asi. It costs 13 tokens per session (1,074 once invoked), scanned A, original, MIT.

A mathematical model for games that can be connected together, with one direction describing play and the other describing returned results such as utilities. It also represents strategies and checks for Nash equilibrium, a state where no player benefits by changing alone.

In plain words
What is it for?
It is for modelling sequential and parallel games, connecting their inputs and outputs, and checking whether a strategy is an equilibrium.
Why use it?
It helps describe interactions between separate games or decision-making systems without treating each full system as one inseparable block.

Skill for Codex

Written for Codex: installed under .codex/.

Good fit It is for modelling sequential and parallel games, connecting their inputs and outputs, and checking whether a strategy is an equilibrium.

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Install with agentmods
npx agentmods add skills/plurigrid/asi/open-games
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 open-games
Clone the repo
git clone --depth 1 https://github.com/plurigrid/asi

Made for: Codex.

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 open-games

README.md
[![agentmods](https://agentmods.dev/badge/skills/plurigrid/asi/open-games/github.svg)](https://agentmods.dev/skills/plurigrid/asi/open-games)
Your own site
<a href="https://agentmods.dev/skills/plurigrid/asi/open-games"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/open-games/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 open-games

Your own site · 80×15
<a href="https://agentmods.dev/skills/plurigrid/asi/open-games"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/open-games.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 13 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,074 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 $0.00013 $0.01074
Opus 5 $0.00006 $0.00537
Sonnet 5 $0.00003 $0.00215
Haiku 4.5 $0.00001 $0.00107

Measured 6d ago against content hash f4b56dc4e3b1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

open-games 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 6d 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/.codex/skills/open-games/SKILL.md · 161 lines

How it starts

The opening of the file, as written. The whole thing — 161 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Open Games Skill (ERGODIC 0)

Compositional game theory via Para/Optic structure

Trit: 0 (ERGODIC)
Color: #26D826 (Green)
Role: Coordinator/Transporter

Core Concept

Open games are morphisms in a symmetric monoidal category:

        ┌───────────┐
   X ──→│           │──→ Y
        │  Game G   │
   R ←──│           │←── S
        └───────────┘

Where:

  • X → Y: Forward play (strategies)
  • S → R: Backward coplay (utilities)

The Para/Optic Structure

Para Morphism

Para p a b = ∃m. (m, p m a → b)
-- Existential parameter with action

Optic (Lens Generalization)

Optic p s t a b = ∀f. p a (f a b) → p s (f s t)
-- Profunctor optic for bidirectional data

Open Game as Optic

OpenGame s t a b = 
  { play    : s → a
  , coplay  : s → b → t
  , equilibrium : s → Prop
  }

Composition

Sequential (;)

G ; H = Game where
  play = H.play ∘ G.play
  coplay = G.coplay ∘ (id × H.coplay)

Parallel (⊗)

G ⊗ H = Game where
  play = G.play × H.play
  coplay = G.coplay × H.coplay

Nash Equilibrium via Fixed Points

isEquilibrium :: OpenGame s t a b → s → Bool
isEquilibrium g s = 
  let a = play g s
      bestResponse = argmax (\a' → utility (coplay g s (respond a')))
  in a == bestResponse

Compositional Equilibrium

eq(G ; H) = eq(G) ∧ eq(H)  -- under compatibility

Integration with Unworld

(defn opengame-derive 
  "Transport game through derivation chain"
  [game derivation]
  (let [; Forward: strategies through derivation
        forward (compose (:play game) (:forward derivation))
        ; Backward: utilities through co-derivation  
        backward (compose (:coplay game) (:backward derivation))]
    {:play forward
     :coplay backward
     :equilibrium (transported-equilibrium game derivation)}))

GF(3) Triads

temporal-coalgebra (-1) ⊗ open-games (0) ⊗ free-monad-gen (+1) = 0 ✓
three-match (-1) ⊗ open-games (0) ⊗ operad-compose (+1) = 0 ✓
sheaf-cohomology (-1) ⊗ open-games (0) ⊗ topos-generate (+1) = 0 ✓

Read the full file on GitHub · 161 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. 6d ago First seen · 161 lines · 13 tokens per session scan A f4b56dc4e3b1

Subscribe to this mod's changes

open-games is a skill published in the GitHub repository plurigrid/asi (62 stars, last pushed 2mo ago), licensed MIT. It adds 13 tokens to every session and 1,074 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 2026-09-03.

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