feat(cloud-agent-next): wire Vercel sandbox billing into SandboxControl

[eshurakov]

Summary

Second chunk of a two-PR stack (stacked on the identity PR). Wires Vercel sandbox usage billing into
the control-plane Durable Object SandboxControl and turns the path on: a persistent,
generation-fenced billing continuation is armed before the sandbox is created, admission happens
before createSandbox, drains reconcile, and settlement is delivered through the heartbeat tick.

Depends on the base branch of this PR (the identity chunk); review that one first.

What it does

• Admission before create — for a creating record whose caller owns createCommands,
  runEnsureReady opens the meter interval (or re-acknowledges it) and arms the continuation before
  createSandbox. Definite rejection: enforced blocks with billing_blocked via failCanonicalCreate;
  shadow continues this create with no interval. Uncertain start: enforced releases creating and
  zero-settles the retained generation; shadow keeps the generation and still creates — a meter outage
  never blocks a shadow create.
• Persistent continuation — one schedule-table entry per open generation, established before
  provider work can remove the creating deadline, marked settlement-due on terminal reconcile and
  removed only on ack or the 60-minute abandon. alarm() re-arms it and, when runtimeDeleted, runs a
  settlement-only path (no getSession, no driveCanonicalStop).
• Prepare vs deliver — afterDrain / afterCanonicalCommit await local preparation and alarm
  composition; meter delivery happens separately, off the billing and heartbeat queues, so a
  heartbeat-triggered budget stop cannot deadlock.
• Evidence — create() stores the session createdAt on the generation binding before returning
  the ref; observe()/stop() store createdAt/stoppedAt/abortedAt. An owned 404 is terminal.
• Provider — create() no longer calls admission; the shared alive/terminal classifier is exported
  and used by both observe() and the billing host.
• Shared admission correction in metered-billing-lifecycle.ts: accept an unmeasured context only when
  there is no pendingStop and the start ack matches; clear only definite rejections.

Verification

• Focused unit tests: 11 files, 276 passed.
• Full cloud-agent-next unit suite: 255 files, 7750 passed, 3 skipped.
• Worker integration suite: 38 files, 750 passed.
• pnpm lint 0/0 and pnpm typecheck exit 0 for cloud-agent-next and container-usage-meter.
• container-usage-meter test:postgres: 15 passed against real Postgres.
• packages/container-usage unchanged.

Not verified

Live Vercel end-to-end has not been run: it requires an enrolled org (VERCEL_SANDBOX_ORG_IDS) plus
the Vercel runtime artifacts and credentials, and the operator SKU rows. Once enrolled, reconcile a
real session's persisted confirmed_seconds against the Vercel session createdAt → stoppedAt.

Scope

Only the sized presets vercel-small / vercel-large are metered. providerSupportsEnforcedBilling('vercel')
stays false, so Vercel is not chosen as the enforced default provider; the unsized default Vercel
destination stays unmetered and fail-closed under enforcement.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

The incremental commit defers the billing continuation while a settlement delivery is in flight and fixes the ensure absent-payload no-clobber; both previously reported findings are resolved on the changed lines.

Files Reviewed (4 files)

• services/cloud-agent-next/src/persistence/SandboxControl.ts
• services/cloud-agent-next/src/sandbox-control/billing-schedule.ts
• services/cloud-agent-next/src/sandbox-control/billing-schedule.test.ts
• services/cloud-agent-next/src/sandbox-control/vercel-billing-control.test.ts

Previous Review Summary (commit a993b11)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit a993b11)

Status: 2 Issues Found | Recommendation: Address before merge

Executive Summary

The Vercel billing wiring is well covered by tests; the main risk is a tight alarm loop in launchVercelSettlement while a settlement delivery is in flight, plus a latent no-clobber bug in the new BillingScheduleTable.ensure.

Overview

Severity	Count
CRITICAL	0
WARNING	1
SUGGESTION	1

Issue Details (click to expand)

WARNING

File	Line	Issue
services/cloud-agent-next/src/persistence/SandboxControl.ts	2462	scheduleAlarm() runs before the in-flight guard, re-arming the expired continuation on every alarm while a settlement delivery is outstanding, producing a tight alarm loop (unbounded if the meter RPC never settles).

SUGGESTION

File	Line	Issue
services/cloud-agent-next/src/sandbox-control/billing-schedule.ts	180	ensure() returns early when the entry is absent and payload is undefined, so an optional-payload call never arms anything. Latent today.

Files Reviewed (14 files)

• services/cloud-agent-next/src/container-usage.test.ts
• services/cloud-agent-next/src/metered-billing-lifecycle.ts - 1 suggestion considered, no issue
• services/cloud-agent-next/src/persistence/SandboxControl.ts - 1 issue
• services/cloud-agent-next/src/sandbox-containers/containers-billing.test.ts
• services/cloud-agent-next/src/sandbox-control/billing-schedule.test.ts
• services/cloud-agent-next/src/sandbox-control/billing-schedule.ts - 1 issue
• services/cloud-agent-next/src/sandbox-control/control-effect-port.test.ts
• services/cloud-agent-next/src/sandbox-control/control-orchestration.test.ts
• services/cloud-agent-next/src/sandbox-control/control-orchestration.ts
• services/cloud-agent-next/src/sandbox-control/lifecycle.test.ts
• services/cloud-agent-next/src/sandbox-control/vercel-billing-control.test.ts
• services/cloud-agent-next/src/sandbox-control/vercel-provider.test.ts
• services/cloud-agent-next/src/sandbox-control/vercel-provider.ts
• services/container-usage-meter/test/postgres.test.ts

Fix these issues in Kilo Cloud

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_{Reviewed by deepseek-v4.1-flash · Input: 0 · Output: 0 · Cached: 0}

_{Review guidance: REVIEW.md from base branch eshurakov/vercel-billing-identity}