Function default_agent_working_dir 

pub fn default_agent_working_dir(agent_name: &str) -> String

The working directory agent.open substitutes when an AgentDefinition’s own working_directory is blank — ~/.agentmux/agents/<name-derived-slug>.

Blank is the DEFAULT for a newly defined agent, so this is the path most agents actually run in. Extracted so agent.open (which creates and uses it) and native-memory resolution (which must find the memories written inside it) share one definition and cannot drift — they previously disagreed, and the resolver simply gave up on a blank field, breaking Memory → Personal for the common case. See docs/specs/SPEC_FIX_PERSONAL_MEMORY_EMPTY_WORKDIR_2026_09_01.md.

NOTE: deliberately NOT derive_slug above. agent.open’s own inline derivation is name.to_lowercase() with a Unicode-aware char::is_alphanumeric() filter (keeping -/_), which differs from derive_slug’s ASCII-only rule, dash-collapsing, 64-char trim and "agent" fallback. Reusing derive_slug here would silently point at a DIFFERENT directory than the one the agent is really running in for any non-ASCII or dash-heavy name. This mirrors the real behaviour exactly.