Commingling under one upstream key is the right transport move. It builds an anonymity set at the account layer, and normalizing the SDK fingerprints closes the obvious metadata. What survives it is stylometric. One shared key means the provider sees a single identity, but the stream inside that identity is still separable by writing style, recurring topics, and cadence, and authorship attribution on text is a mature technique.
Traffic mixing on the roadmap handles the timing axis. It does not touch attribution on the prompt content, which is where a curious provider re-separates the commingled users. Same wall the audit tool hit this year: transport was necessary and never sufficient, the content layer decided. Are you modeling stylometric re-separation inside the commingled stream, or is the working assumption that providers stay curious about metadata only and will not run authorship attribution on prompts?
Commingling under one upstream key is the right transport move. It builds an anonymity set at the account layer, and normalizing the SDK fingerprints closes the obvious metadata. What survives it is stylometric. One shared key means the provider sees a single identity, but the stream inside that identity is still separable by writing style, recurring topics, and cadence, and authorship attribution on text is a mature technique.
Traffic mixing on the roadmap handles the timing axis. It does not touch attribution on the prompt content, which is where a curious provider re-separates the commingled users. Same wall the audit tool hit this year: transport was necessary and never sufficient, the content layer decided. Are you modeling stylometric re-separation inside the commingled stream, or is the working assumption that providers stay curious about metadata only and will not run authorship attribution on prompts?