Function resolve_shared_claude_provider_dir 

fn resolve_shared_claude_provider_dir() -> PathBuf

The directory a spawned Claude agent’s CLAUDE_CONFIG_DIR env var points at by DEFAULT (agents not bound to an account — the common case; an agent bound to an account uses that account’s own dir, which this does not cover). Mirrors agent_open.rs’s own auth_dir resolution exactly — DataPaths::provider_auth_dir("claude"), with the identical ~/.agentmux/shared/providers/claude fallback when DataPaths::from_env() fails — so the path shown here is genuinely the one AgentMux itself uses when launching a Claude agent, not a guess. codex P1, PR #2794: the original version read ~/.claude/CLAUDE.md directly, which SPEC_PROVIDER_ISOLATION_2026_06_20.md §5b confirms is NOT what a CLAUDE_CONFIG_DIR-redirected spawned agent actually loads as its “user CLAUDE.md” — CLAUDE_CONFIG_DIR relocates Claude Code’s entire home, <CLAUDE_CONFIG_DIR>/CLAUDE.md included.