# Sandbox Timer

> Idle-sandbox guard for AI agents. Your agent sends its running E2B, Vercel Sandbox, Daytona or Modal sessions; Sandbox Timer flags the idle ones, shows what idle time cost at the hourly rates you give it, and with Pro at $9 a month returns the ready-to-run kill call for each. A guard on top of your sandboxes, not a sandbox. It never holds your provider keys.

## Connect
- MCP (streamable HTTP): https://timer.cloudforbots.com/mcp
- Claude Code: `claude mcp add --transport http sandbox-timer https://timer.cloudforbots.com/mcp`
- REST: `POST https://timer.cloudforbots.com/api/run/<tool>` with JSON args. OpenAPI: https://timer.cloudforbots.com/openapi.json
- Auth: optional `Authorization: Bearer <key>`. Free key: `POST https://timer.cloudforbots.com/api/key`

## Pricing
- Free: 500 calls/day (daily, not a trial). No signup.
- Pro: $9/month, 50000 calls/day: https://pay.instaloops.com/b/3cI3cv55uffh0ez4Kr83C3C
- Bring your own model. Works with Claude, Codex, ChatGPT, Grok Bot.

## Tools
### track_sessions
Send your agent's running sandbox sessions (up to 200; call it on a heartbeat, e.g. every 5 minutes) and get back which are idle past your threshold or over their max lifetime, the dollars idle time has cost at the hourly rates you pass, and what to do. Pro acts: returns a ready-to-run kill call per idle sandbox for its provider (E2B kill, Vercel Sandbox stop, Daytona stop, Modal terminate) and POSTs one alert per sandbox to your webhook. Free watch-only returns would_kill and sends nothing. We never hold provider keys and never kill anything ourselves: your agent runs the call with its own key.
Inputs: `fleet` (string), `sessions` (array, required), `idle_minutes` (integer), `max_lifetime_minutes` (integer), `rates_per_hour` (object), `alert_webhook` (string)

### idle_report
Which sandboxes were flagged idle and what idle time cost, per provider, from what track_sessions has seen. Without an API key pass fleet. With a key: every fleet on it. Free shows 7 days, Pro 30.
Inputs: `fleet` (string), `days` (integer)

### set_idle_rules
Pro: save the rules track_sessions applies to a fleet: idle_minutes threshold, max_lifetime_minutes, default rates_per_hour by provider, and alert_webhook. Free returns a preview of the rules and saves nothing (pass the same values on each track_sessions call instead).
Inputs: `fleet` (string), `idle_minutes` (integer), `max_lifetime_minutes` (integer), `rates_per_hour` (object), `alert_webhook` (string)

### weekly_report
Plain-English summary of the last 7 days: sandboxes watched, how many sat idle, dollars idle time cost at your rates, kill calls returned (Pro) or that would have been (free). Read-only; sends nothing. Needs a free API key.
Inputs: none

### usage_and_upgrade
Usage today + upgrade link (not metered).

## FAQ
### What problem does this solve?
Cloud sandboxes bill per second while they run, busy or not. Agents open them for a task and often leave them running. Sandbox Timer watches the sessions your agent reports, flags the ones that went quiet, and shows what that idle time cost.

### Is it a sandbox?
No. It is a guard on top of the sandboxes you already use (E2B, Vercel Sandbox, Daytona, Modal or any other). It never runs your code.

### How does my agent send sessions?
Call track_sessions on a heartbeat (for example every 5 minutes) with the list your agent already has: id, provider, idle_minutes or last_activity_at, and optionally rate_per_hour. Use relative fields like idle_minutes if clocks differ.

### Do you guess sandbox prices?
No. We never look up or guess a price. You pass rate_per_hour per sandbox, or rates_per_hour per provider, from your own price page or bill. Without a rate, idle minutes are counted but not priced.

### Do you hold my E2B, Vercel, Daytona or Modal keys?
No. Sandbox Timer never asks for or stores provider keys and never stops a sandbox itself. Pro returns the kill call (SDK and REST, with a key placeholder) for your agent to run with its own key.

### What is watch-only mode?
The free plan flags idle sandboxes, counts the dollars at your rates and keeps a 7-day report. Flagged sandboxes come back as would_kill, with no kill call. Nothing is sent and nothing is stopped.

### What does Pro do?
Returns the ready-to-run kill call for each idle sandbox (E2B kill, Vercel Sandbox stop, Daytona stop, Modal terminate), saves idle rules per fleet with set_idle_rules, posts one alert per sandbox to your webhook, keeps 30 days and allows 50,000 calls a day.

### My provider already has a timeout. Why this?
Use it: E2B, Vercel Sandbox, Daytona and Modal all let you set a timeout or auto-stop when you create a sandbox. Sandbox Timer adds an idle check across every provider at once, the dollars idle time cost, and a kill call when a sandbox is quiet long before its timeout. It does not replace them.

### Is there a model inside?
No. Bring your own model. Sandbox Timer only does the clock math on the sessions you send.

### What does it cost?
Free: watch-only, 500 calls a day, 7 days of history. Pro is $9 a month. It is also included in the Cloud for Bots All Access bundle.

Publisher: Supa Humans (https://supahumans.ai). Marketplace: https://botrecipe.com/tools/