First session in a new folder does not load AGENTS.md (2.1.296)

What happened

In a folder where Claude Code has never run, the first interactive session does not load the repository's root AGENTS.md. /context all lists only ~/.claude/CLAUDE.md under Memory files. Every later session in the same folder loads AGENTS.md.

Environment

• Claude Code 2.1.296, native install, Linux (WSL2 Ubuntu), Claude Max, model claude-opus-5-5, effort max.
• The repository has a root AGENTS.md and no CLAUDE.md, .claude/CLAUDE.md or CLAUDE.local.md in the folder or above it. The user has a ~/.claude/CLAUDE.md.
• Each new folder was a git worktree of that repository, created by an IDE that runs git worktree add. Sessions started in that IDE's terminal with claude --model claude-opus-5-5 --effort max; the terminal environment was the same for first and later sessions.
• User and plugin SessionStart hooks are installed. They add context only, and they ran identically in first and later sessions.

Steps to reproduce

1. Create a git worktree of a repository that has a root AGENTS.md and no CLAUDE.md, in a new folder where Claude Code never ran.
2. Start claude in that folder and run /context all. Memory files lists only ~/.claude/CLAUDE.md.
3. Run /exit, start claude again in the same folder, and run /context all. Memory files lists ~/.claude/CLAUDE.md and AGENTS.md.

Observed

• 2 of 2 new folders: the first session missed AGENTS.md (total context 45.5k and 45.6k tokens).
• 5 of 5 later sessions in those folders loaded it (AGENTS.md 7.1k tokens, total 52.6k to 52.7k), with and without project settings changes.
• The only per-folder state we found written by the first session is a githubRepoPaths entry in ~/.claude.json. No projects entry is created for the worktree path.

Expected

The memory docs say AGENTS.md loads at session start when no CLAUDE.md exists. Their only first-session caveat is the first session after an upgrade from v2.1.276 or earlier, which does not apply here.

Impact

A tool that starts an agent in a fresh worktree per task runs that agent's whole first session without the project's instructions.