yaver_auth_start · Yaver MCP: Risk & Policy

WHAT IT DOES

What yaver_auth_start does on Yaver

AI agents invoke yaver_auth_start 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.

PARAMETERS

Parameter	Type	Required	Description
`convex_url`	string	—	Optional override for the Convex backend URL (defaults to the stored or hosted endpoint).

Parameters from the server's own tool schema.

WHY IT NEEDS A POLICY

Why yaver_auth_start needs a policy

yaver_auth_start triggers real processes with real consequences. An agent gone sideways doesn't fire it once — it starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

yaver_auth_start Rate-limited

yaver_auth_start stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "yaver_auth_start": {
      "limits": [
        {
          "counter": "yaver_auth_start_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Yaver, so you can run agents against it safely.

FAQ

Questions about yaver_auth_start

What does the yaver_auth_start tool do? +

Start a headless device-code sign-in for Yaver (Apple / GitHub / Google / Microsoft OAuth). Returns {url, user_code, device_code, qr_ascii, expires_at_ms}. Render the URL + QR to the user; they open it on their phone or laptop browser, sign in, and confirm the code. Then call yaver_auth_wait (or loop yaver_auth_poll) with the device_code to finish. Non-blocking — this tool does not wait for the user. It is categorised as a Execute tool in the Yaver MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

What parameters does yaver_auth_start accept? +

yaver_auth_start accepts 1 parameter: convex_url. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on yaver_auth_start? +

Register the Yaver MCP server in PolicyLayer and add a rule for yaver_auth_start: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Yaver. Nothing to install.

What risk level is yaver_auth_start? +

yaver_auth_start is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit yaver_auth_start? +

Yes. Add a rate_limit block to the yaver_auth_start rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block yaver_auth_start completely? +

Set action: deny in the PolicyLayer policy for yaver_auth_start. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides yaver_auth_start? +

yaver_auth_start is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.