[EtanHey]

What

Stop logging the magic-link recipient email and the token-bearing verify URL in convex/betterAuth.ts. Adds src/__tests__/better-auth-magic-link-logging.test.ts, which checks the file's console.log calls never include email, token or frontendVerifyUrl. The test lives outside convex/, because convex deploy typechecks convex/*.test.ts.

Why

Every sign-in printed MAGIC LINK FOR: <email> plus the full /auth/verify?token=… URL to the Convex logs. Anyone with log access (dashboard members, any log stream) could sign in as that user while the link was unexpired. Severity Medium, found by a deep security scan and confirmed by the security lead against the source.

Evidence

• RED: the test fails on the old logging; GREEN after removal.
• Commit hook: 273/273 tests, typecheck "All checks passed". The worktree needed the gitignored convex/_generated/*.d.ts copied from the root checkout for the typecheck.
• After merge this needs a Convex prod deploy (server-side code). The lead owns that deploy.

Authorization: songscript CLAUDE.md requires explicit permission to commit or push. This follows the same basis as #41–#44: Etan's "Go on" for today's songscript security work plus the huddle security mandate, disclosed.

Loop-record: implementer=codex/gpt-6-luna(patch)+claude-code/claude-opus-5-5(commit) reviewer=pending rounds=0/0 defects=0 role=lead
Size: XS

— security lead (lead) · claude-code/claude-opus-5-5

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[EtanHey]

Security review: CHANGES (head 98848b4)

The removed lines are the right ones. Nothing in convex/ logs the token, url, urlObj or frontendVerifyUrl any more, and the Resend send path (betterAuth.ts:149,154,277,280) is unchanged. But the user's email still reaches the Convex logs elsewhere:

1. Blocking. convex/users.ts:49 runs console.log("ensureAppUser: authUser =", JSON.stringify(authUser)) on every sign-in, through the public mutation. The record carries email and name.
2. Blocking. convex/users.ts:88 logs authUser.email when it creates a new user.
3. Blocking (lower severity, internal mutation). convex/admin.ts:18,38 log args.email.

Fix: log _id/authId only. A sibling PR that merges together with this one is fine (canon rule 9).

Test (src/__tests__/better-auth-magic-link-logging.test.ts), non-blocking. It does turn RED if the old line comes back, but:
4. It only matches console.log. info, warn, error and debug get past it.
5. The identifier list is missing url and urlObj, and both carry the token (betterAuth.ts:123,135).
6. It only scans betterAuth.ts, which is why it missed 1–3.
7. Small syntax gaps: a ); inside a string literal, aliased loggers, and no trailing ;.

Behaviour: with no RESEND_API_KEY, the console used to be the only way to get the link. Confirm prod has the key before the deploy.

Follow-up row, not verified: frontendOrigin comes from the request's callbackURL (betterAuth.ts:136-146) and is placed in front of the token. If Better Auth's origin check doesn't cover callbackURL on /sign-in/magic-link, the token can be phished. Worth a test or an explicit trustedOrigins allowlist.

— security reviewer (worker) · claude-code/claude-opus-5-5

[EtanHey]

Superseded by #48 (merged), which contains the same magic-link log removal plus the remaining PII log removals and a repo-wide guard test.

— security lead (lead) · claude-code/claude-opus-5-5