Map: exarch / tools

ral is exarch’s one tool. Every other harness affordance the model once reached as a provider-advertised Tool — spawning, messaging, cancelling, scheduling, replying, and reading a reply — is now a ral builtin reached by writing ral inside ral itself, per the agent-tool-to-exarch-builtin migration; see builtins for the verbs and engine-protocol for the desk they speak through. shell_eval/tools.rs shrinks to:

• ral (shell_eval/tools/ral.rs) — the one call that crosses the provider boundary: evaluate ral source against the session shell, synchronously, through `run_shell`. Its input is a required cmd (the ral source) and a required one-line description (shown on the rail; the full cmd opens in the collapsible tool-call block; oversize descriptions are truncated, never rejected). An optional timeout_secs bounds the call, defaulting to CALL_TIMEOUT_SECS (60s) — a default, not a cap: raise it for known-long work, or spawn what should outlive the run. A call the wall cuts short loses its bindings and keeps its acts, so its stderr carries the engine’s span, the remedy, an audit of what already stands, and the deferred workers still running past the wall with nothing left to await them by (shell-eval). Every accepted or malformed call emits a Display::ToolCall followed by a Display::Result addressed by the call’s BlockId, so a result never has to search backward for its tool row. Malformed JSON uses <invalid input> as the call label but still gets a paired diagnostic result; if the call row itself cannot be appended, the seam reports a transient fault and cannot invent a result target.
• shell_eval/tools/agent.rs — no longer a tool module, but the fork-detach-register spine every launch shares: spawn_async, AsyncSpawn, SpawnedChild. Both /branch’s spawn_branch and the desk’s agents `start handler build on it — either arm of it, in-process or across a wire — so /branch and the harness spawn verb share one mechanism (agents, agent).

The harness verbs are answered by the ExarchDesk (exarch/src/fleet/desk.rs), installed per ral call and reached through shell.enquire(...) from the builtin’s body; acting verbs emit Display::HarnessCall/Forensic::HarnessResult and, on the arm where the act genuinely landed, file it in the call’s act ledger for the audit every raise owes the model (shell-eval). They are rendered as acts — verb, subject, payload rows that never fold into an observation run (harness-calls-are-acts; spawns additionally derive a child tab) — while listings stay silent since their value is the returned record. There is no Gate/tools_for axis any more — a fresh model never even sees a verb the desk would certainly refuse: agents is dropped from the per-agent builtin index when the agent neither spawns nor returns (its `reply needs only returns, so a fuelless returning leaf keeps the verb), and the self-wakeup family when the agent lacks the schedule grant (prompt.rs’s BuiltinIndex, resolved once against the boot shell), while authority itself is still enforced only at the desk, never by omission.