Allow Claude to invoke /rename programmatically from within a session

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When running many concurrent sessions (8-10+), session names are the primary way to distinguish them at a glance. Currently /rename is a harness-level command that executes before Claude's turn, so Claude cannot invoke it from inside a session in response to a user request like "rename this session to X."

Current behavior

• /rename works when typed manually in the prompt
• Claude cannot trigger /rename on behalf of the user — the command never reaches Claude's context

Proposed Solution

Desired behavior

• User can say "rename this session to '958904 — mcp-ado fix'" and Claude invokes the rename without the user typing the command manually
• Or: expose /rename as an invocable built-in so the harness can call it when Claude emits the appropriate signal

Alternative Solutions

_No response_

Priority

Low - Nice to have

Feature Category

CLI commands and flags

Use Case Example

Use case
Power users running many parallel sessions need meaningful names set early (often based on what Claude discovers about the ticket/task) rather than having to manually /rename after the work context is clear.

Additional Context

_No response_