Account rotation — credential adapter

Choose the credential tool from both host and agent family, perform only the explicit account switch, and report the identity observed by the matching runtime.

Verifying identity through the target runtime works because the runtime is the only party whose opinion matters: credential files can be swapped perfectly and still authenticate as the old account in an already-running process.

Named failure mode — stale-process identity: declaring the rotation done while every live session still holds the previous account's tokens in memory.

Anti-pattern: confirming a switch by diffing credential file bytes. Corrective: ask the matching runtime who it is now, and report whether a new process is required for the answer to hold.

Boundary

• Perform only the account switch the caller explicitly authorized; rotation mutates host credential state and is never implied by repository access.
• The credential tool is caller- or operator-selected per host and agent family; the names below are this operator's routes, not a universal prescription. On macOS with Claude credentials the route is claude-acct (Keychain-backed); file-backed Codex, Gemini, Linux, or WSL credentials use caam. Never use caam for macOS Claude account operations.
• Verify account identity through the target runtime; token bytes are not account identity.
• If neither the selected credential tool nor a runtime identity probe is available, report that absence as a disclosed fact and stop. Never fall back to diffing credential-file bytes to declare a switch done.
• Existing processes retain credentials already loaded in memory. Rotation affects a new process.
• This skill does not restart work, resume a task, select a pane, move repository state, or decide what happens after the switch.

Return the host, agent family, selected tool, requested account/profile, the identity observed before and after the switch, whether any live runtime still holds the previous account (a partial rotation), the command exit code, and whether a new process is required for the new identity to hold.