claude.ai Project session ignores a matching project doc and misroutes a simple task for ~90 minutes

Concerns claude.ai (web), a cloud session bound to a Project, not the CLI. Model: Claude Opus 5.5. CLI-only template fields: not applicable.

9 Oct 2026, about 90 minutes in the afternoon, Eastern.

The user sent a screenshot of an ad on a YouTube channel they manage and asked for the advertiser and its ad category to be blocked.

The project already had a doc for exactly this task, listed in the session's own project context. It describes the route (YouTube Studio > Monetization > Ad categories) and logs earlier blocks.

Claude never read it. Instead it:

• treated the request as the user's personal Google ad settings and called it impossible
• used a browser the user had not chosen, against their preferred-browser setting
• asked them to change a setting on the wrong account, which the auto mode classifier then blocked (see #100730)
• confused which account the channel belonged to
• asked clarifying questions already answered

About 15 user turns later, Claude opened the doc. The task then took a few minutes.

Expected: when a session is bound to a project, Claude reads the project docs that match the request before choosing a route. The doc's title alone matched the request.