User audio is private creative material and is treated as sensitive by default. This document records the baseline established in M13. It is a baseline, not a completed production posture — open items are listed at the end.

• Uploaded and processed audio is written under a private work root (<temp>/drakotune_web/<job_id>/), never inside the repo or a public directory.
• Files are reachable only through the app's controlled routes. There are no public audio URLs and no directory listing.

• Every playback URL is an HMAC-signed, time-limited capability (?exp=<unix>&sig=<hmac>), minted per request with a default TTL of 1 hour.
• The audio route verifies the signature (constant-time compare) and expiry before serving; unsigned, tampered, expired, or wrong-resource requests get 403 — checked before existence, so a missing job is indistinguishable from a real one without a valid token.
• Signing secret comes from DRAKOTUNE_SECRET. If unset (dev only), a random per-process secret is used (security.IS_EPHEMERAL == True) and tokens do not survive a restart. Set DRAKOTUNE_SECRET in any shared/production deployment.

• DELETE /api/jobs/{id} removes the job and its working files.
• cleanup_expired() deletes jobs older than the retention window (RETENTION_SECONDS, default 1 hour).
• The entire work root is removed on process exit (atexit).

• No third-party service receives user audio (Bible rule). All processing is local.
• Reports avoid embedding secrets or PII; audio is not logged.

• The deterministic core runs fully offline via the CLI (python scripts/run_alpha.py <file> --plan); the web layer can be disabled without affecting local processing.

• No user accounts / authentication or per-user authorization (jobs are not owned).
• No rate limiting or upload size/type hard limits at the edge.
• No persistent audit log.
• cleanup_expired() is not yet scheduled by a background task.
• Signed-URL secret rotation is manual.

These are tracked for production hardening (post-M16) and must not be assumed complete. Do not describe DrakoTune as "secure" or "production-ready" on this baseline alone.