Subagent sent the user's email from session context in a User-Agent header

A research subagent put the signed-in user's email, which Claude Code adds to session context, into the User-Agent of an outbound request to a third-party site. The session context tells the model never to send that email to an unrelated service in a header, URL or payload unless the user asks. The user didn't ask.

The request, with the email redacted:

curl -s -o /dev/null -w "%{http_code}\n" -A "ThaneholdResearch/1.0 (<user email>)" --compressed "https://liquipedia.net/warcraft/Armor"

It returned 403. The model added the contact because Liquipedia asks API clients for one in the User-Agent.

• Claude Code 2.1.285, desktop app Code tab, macOS
• claude-opus-5-5 at max effort with extended thinking
• A web research subagent spawned by another subagent, with WebSearch and WebFetch
• 2026-10-12 08:44 UTC

Expected: the model leaves the user's email out of outbound requests or asks first, for example by sending a User-Agent with no contact or skipping the site.