# exec_command

Execute a shell command on this machine or an owned remote Yaver device and return the output. Commands are validated through the sandbox (dangerous patterns like rm -rf / are blocked). Use this for quick commands — for long-running tasks, use create_task instead.

Agent View of the PolicyLayer registry record for `exec_command`. HTML page: https://policylayer.com/tools/io-github-kivanccakmak-yaver/exec-command

## Facts

- Tool: `exec_command`
- Server: Yaver (`yaver-cli`) — https://policylayer.com/tools/io-github-kivanccakmak-yaver.md
- Install: `npx -y yaver-cli`
- Homepage: https://github.com/kivanccakmak/yaver.io
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 4 (1 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `command` | string | yes | Shell command to execute |
| `timeout` | integer | no | Timeout in seconds (default: 300, max: 3600) |
| `work_dir` | string | no | Working directory (default: agent's work dir) |
| `device_id` | string | no | Optional owned Yaver device id/name/alias to run on, e.g. a self-hosted dev box. |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "exec_command",
    "arguments": {
      "command": "<command>"
    }
  }
}
```

## Why exec_command is rated High

This tool triggers external operations (shell commands) whose effects depend entirely on arguments supplied by the agent. While sandbox restrictions reduce severity from critical to high, the capability to execute arbitrary commands on local and remote machines represents significant blast radius if misused (unauthorized file access, data exfiltration, lateral movement).

From the tool's own definition: "The tool explicitly states it 'Execute[s] a shell command on this machine or an owned remote Yaver device and return[s] the output.' Shell command execution is the defining characteristic of the Execute category."

## Use case

AI agents invoke exec_command to trigger actions in Yaver. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Yaver:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "exec_command": {
      "limits": [
        {
          "counter": "exec_command_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Yaver (644)

- `acl_remove_peer` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/acl-remove-peer.md
- `cancel_schedule` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/cancel-schedule.md
- `cloud_destroy` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/cloud-destroy.md
- `companion_down` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/companion-down.md
- `data_delete` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/data-delete.md
- `db_push` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/db-push.md
- `db_reset` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/db-reset.md
- `db_restore` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/db-restore.md
- `dns_flush` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/dns-flush.md
- `dns_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/dns-remove.md
- `docker_prune` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/docker-prune.md
- `docker_rm` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/docker-rm.md
- `docker_rmi` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/docker-rmi.md
- `feedback_delete` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/feedback-delete.md
- `forgot_password` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/forgot-password.md
- `git_member_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/git-member-remove.md
- `git_stash` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/git-stash.md
- `guest_delete` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/guest-delete.md
- `guest_revoke` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/guest-revoke.md
- `jobs_cancel` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/jobs-cancel.md
- `machine_onboarding_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/machine-onboarding-remove.md
- `machine_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/machine-remove.md
- `migrate_rollback` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/migrate-rollback.md
- `models_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/models-remove.md
- `monitor_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/monitor-remove.md
- `phone_project_delete` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/phone-project-delete.md
- `proxy_remove` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/proxy-remove.md
- `relay_clear_password` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/relay-clear-password.md
- `release_rollback` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/release-rollback.md
- `remote_destroy` — Destructive — https://policylayer.com/tools/io-github-kivanccakmak-yaver/remote-destroy.md
- …and 614 more: https://policylayer.com/tools/io-github-kivanccakmak-yaver.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-kivanccakmak-yaver · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-kivanccakmak-yaver