Leaderboard / Case No. FB-2026-07-31-anthropic-moonshot-thinking-signature-replay
Moonshot saved Claude's "thinking signatures", started new sessions and got Claude to convert them back into the full reasoning traces, defeating Anthropic's anti-distillation control to harvest chain-of-thought data for training its Kimi models.
Score breakdown
| Component | Value | Reasoning |
|---|---|---|
| Sentence-Years | 35 | 17 USC 1201(a)(1)(A), 18 USC 1832, 18 USC 1343 |
| × Contribution | 2 | Ran the operation: Anthropic says Claude returns "a reference to its raw thinking as a 'thinking signature'" to mitigate distillation, and that Moonshot circumvented this by "eliciting Claude to convert the reasoning signature back into the full reasoning trace" in a new session; the owner ruled that this is Claude doing the work of the evasion, so Claude ran the operation. The circumvention charge (17 USC 1201, criminal under 1204) and trade-secret theft are contested because the copyrightability and trade-secret status of model output are unsettled, and Anthropic ties Moonshot to "a proxy service network of 5,380 fraudulent accounts", which supports wire fraud. |
| × Blast Radius | 0.5 | Own lab's production: The victim is Anthropic, the lab whose own model did the work, so blast radius is own lab's production. |
| × Legal status | 0.5 | Legality contested. |
| + Tradecraft | 2 | Converting the signature back into the raw trace defeated a technical control that exists to stop distillation, which is scored as evasion. |
| + Guardrails | 0 | Guardrails intact: No jailbreak is reported; Claude was used as shipped, so guardrails are scored intact. |
| + Dwell Time | 0 | Anthropic attributes Moonshot's traffic to "between May and July 2026" without a start date, so date_precision is before with 2026-07-31 as the latest possible date; dwell is 0 days counted from it and never inflated, and Anthropic detected it itself. |
| Total | 19.5 |
Charges the human could face
17 USC 1201(a)(1)(A)Up to 5 years18 USC 1832Up to 10 years18 USC 1343Up to 20 years