Agent Teams (tmux mode): named teammates start in $HOME instead of inheriting the lead's working directory

Environment

• Claude Code: 2.1.199
• OS: macOS (Darwin 25.5.0)
• Settings: CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1, "teammateMode": "tmux"

Bug

When the lead session spawns named teammates via the Agent tool (e.g. subagent_type: "general-purpose", name: "smaug-clip-research"), the teammate's session starts with cwd=$HOME instead of the lead's working directory.

The lead was running in a project repo (~/Documents/<org>/<repo>). Eleven teammates spawned from that session in one evening (one research agent plus a verify-0–verify-9 fan-out) all recorded "cwd": "/Users/<user>" in their session transcripts, which landed under ~/.claude/projects/-Users-<user>/ rather than the lead's project directory.

Expected

Teammates inherit the lead session's working directory, matching how in-process subagents behave.

Impact

• Repo-relative paths in spawn prompts silently resolve against $HOME. The work only succeeded because the spawn prompts happened to contain the absolute repo path.
• Teammates read/write in $HOME — a directory the user never opened a session in or trusted.
• A project entry for /Users/<user> is auto-created in ~/.claude.json (with hasTrustDialogAccepted: false), and teammate transcripts accumulate under ~/.claude/projects/-Users-<user>/, detached from the real project.
• Teammates load the wrong project context ($HOME has no project CLAUDE.md, MCP config, or skills).

Likely mechanism

tmux-spawned panes appear to get the tmux server/session default directory rather than being launched with -c <lead cwd> (or equivalent). The docs at https://code.claude.com/docs/en/agent-teams don't specify teammate cwd behavior, and there's no setting or hook to pin it.

Related

#23669 and #59838 ask for per-teammate cwd control; this issue is about the default being wrong in tmux mode — the default should be the lead's cwd.