# Primary-source ledger

Sources inspected on 6 September 2026 JST. These motivate the design and are not pooled with our observations. The versioned URLs identify the exact research texts used. This is a focused related-work review, not a systematic review.

| Source | Relevance and boundary |
|---|---|
| Keppo et al., [On the Fragility of AI Agent Collusion, v1](https://arxiv.org/html/2603.20281v1), March 2026 | Separates asymmetries in model size, information and patience. Their model-size treatment retained elevated prices, whereas other asymmetries could weaken coordination. Their longer horizon and model choices differ from ours; size asymmetry does not establish a universal increase in collusion. |
| Agrawal et al., [Evaluating LLM Agent Collusion in Double Auctions, v1](https://arxiv.org/html/2507.01413v1), 2025 | Studies communication, model choice and competitive pressure in double auctions. Motivates checking communications alongside objective payoffs. We use a logit pricing market and arithmetic settlement, so this is not a direct replication of its auction results. |
| Bianchi et al., [How Well Can LLMs Negotiate?](https://proceedings.mlr.press/v235/bianchi24a.html), ICML 2024 | NegotiationArena shows why negotiated payoff and benchmark competence should be measured separately. Particular social tactics can matter in particular negotiations; the paper does not establish a universal benefit of deception or verbosity. |
| Bergemann et al., [Training Language Models for Bilateral Trade with Private Information](https://cowles.yale.edu/research/cfdp-2514-training-language-models-bilateral-trade-private-information), CFDP 2514, April 2026 | Motivates private valuations and a binding structured offer separate from nonbinding dialogue. Our small finite-turn environment is not a replication of its 15,000-negotiation study. |
| [A2A Python SDK v1.1.2](https://github.com/a2aproject/a2a-python/tree/v1.1.2) | Source for the pinned transport SDK. Actual local HTTP evidence is exported. A2A transports messages; the experiment controller implements the economic game. |
| [Claude Code CLI reference](https://code.claude.com/docs/en/cli-reference) | Headless output, model selection and restrictions were checked against local CLI help. Retained metadata reports auxiliary-model usage. |
| [OpenAI Codex configuration reference](https://learn.chatgpt.com/docs/config-file/config-reference) | Configuration isolation and tool/plugin controls were checked against local CLI behavior and the official reference. A requested model identifier is not independent backend attestation. |

Antigravity CLI's locally returned model catalogue and help were the operational evidence for the Gemini adapter. It is not the standalone Gemini CLI. We do not cite documentation for a different CLI as evidence of Antigravity behavior.

No private chain-of-thought is used to establish intent. Short requested action notes and final messages are observable behavior; statements of intent can be mistaken, strategic or nonbinding.

Microsoft [SetThreadExecutionState](https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setthreadexecutionstate) was checked for the temporary runtime follow-up request. ES_CONTINUOUS with ES_SYSTEM_REQUIRED prevents idle sleep while held, and is cleared on exit; it does not prevent explicit user sleep or lid actions. The bounded host-power-event census is an original local observation, not derived from this documentation.
