fix: preserve PostHog cookieless identity fields

[flamboh]

Note

🤖 GPT-5.6 Sol on behalf of Oliver

problem

Tagium's privacy sanitizer removed PostHog fields required for cookieless identity. PostHog needs $cookieless_mode, $raw_user_agent, $host, and the request IP; missing $host causes the event to be dropped before identity generation.

This does not fix PostHog's query-time traffic classification. PostHog deliberately removes the raw user agent and IP after computing the cookieless identity, so stored cookieless events may still appear as Automation / no_user_agent.

solution

• preserve $cookieless_mode: true
• preserve raw user agents up to PostHog's 1,000-character limit
• preserve only the canonical host for the active app: tagium.app or save.tagium.app
• scope the host and raw-user-agent exceptions to cookieless events
• keep rejecting URL-shaped, empty, foreign, and wrong-app host values

human review

Setup: use the production PostHog project with cookieless server hash mode enabled and send fresh events through t.tagium.app.

1. Exercise both tagium.app and save.tagium.app.
2. Confirm fresh events no longer produce cookieless_missing_host ingestion warnings.
3. Confirm identities are server-generated rather than left as $posthog_cookieless.
4. Confirm the proxy forwards the real client IP.
5. Confirm stored events do not retain $raw_user_agent or $ip.

Important edge cases: malformed, empty, foreign, wrong-app, and non-cookieless host inputs are rejected. Historical dropped events cannot be repaired.

Decision for review: this PR improves cookieless ingestion and identity quality only. Query-time bot classification remains an upstream PostHog limitation; the app does not duplicate raw identifiers to bypass PostHog's privacy boundary.

Automatically verified with 100 test files / 660 tests, TypeScript typecheck, targeted lint, and diff validation. The PostHog project setting and production proxy IP behavior still require manual verification after deployment.

Changes were implemented and reviewed by GPT-5.6 Sol and GPT-5.6 Luna in T3 Code through the Codex harness.

[github-actions]

React Doctor found no new issues. 🎉

_{Reviewed by React Doctor for commit f03b55c.}

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Status	Name	Latest Commit	Preview URL	Updated (UTC)
✅ Deployment successful! View logs	tagium	f03b55c	Commit Preview URL Branch Preview URL	Aug 30 2026, 06:13 PM