[rbartoli]

This is steal (8), the top one, from the 2026-10-23 competitor check (internal note, Q3). Every rival that acts shows its state live; this guard showed it only in /agent-guard status.

While agents run on this machine, or the guard is asking, holding or has just refused something, a line above the prompt (the AbovePrompt band) shows it:

Usage guard · 3 of 4 agents running · 5 of 12 started in the last 10 min · last refusal 14:22: concurrency

What it shows

• Agents running and started across every session on the machine, against their limits.
• An open question ("asking you about starting agents" or "asking you about the context size").
• "new agents declined until …", "agent spawns paused until …" (the fuse), and the last refusal in the window, with its rule.

How it behaves

• Style: dim normally, bold once a limit is reached or something is held, and gone when there's nothing to say. Claude Code's [-] collapses it.
• Stays current in a quiet session: a timer redraws it when a start, refusal, decline or pause ages out.
• Shares the slot: it draws its line and keeps whatever the engine or other plugins draw beneath. It yields to a survey (hasSurvey).
• Interactive only: headless sessions draw nothing.
• Status line unchanged: plan windows and context stay there.

How it's built

• Core: bandLine() and bandExpiry() in core/status.ts stay pure. Each Denial now records its rule, so the band can name it.
• Adapter: refreshStatus writes the line to $.state (agent-usage-guard.band, declared in the new types/index.d.ts contract named in plugin.json) only when it changed. A ui.render hook on AbovePrompt draws from it with plain h() calls, so the module stays .ts. The band also refreshes when the session publishes its counts and when a question opens or closes.
• Test harness: stands in for the engine's empty band, and gains questionHeld to keep a question open while a test looks.

Distribution step once this ships: a short clip of the band filling during a burst.

Test plan

• New tests/band.test.ts, on terminal and desktop: nothing shows with nothing to say; 2 local + 1 peer agents show as "3 of 4 running · 3 of 12 started"; an open question shows while it's asked, then the decline and last refusal; it clears by itself 10 minutes later in a quiet session; a headless session draws nothing
• claude plugin test . on 2.1.310: 108 pass. With the code stashed, the three band tests that expect a line fail.
• claude plugin validate . --strict lists the hook and the agent-usage-guard.band state reads and writes against the contract; tsc is clean
• Live in the real UI (2.1.310, tmux, --plugin-dir, installed copy switched off, a seeded peer record in the dev store, restored afterwards): Usage guard · 2 of 4 agents running · 2 of 12 started in the last 10 min drew above the prompt with the engine's [-]. No model turn ran.
• CI is green