code_attach · Yaver MCP: Risk & Policy

WHAT IT DOES

What code_attach does on Yaver

AI agents use code_attach to create or update resources in Yaver — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Yaver environment.

PARAMETERS

Parameter	Type	Required	Description
`target`	string	Yes	Device ID or machine name to attach to
`username`	string	—	Optional owner email hint when machine names collide
`device_id`	string	—	Optional remote device ID whose local code-control plane should be updated

Parameters from the server's own tool schema.

WHY IT NEEDS A POLICY

Why code_attach needs a policy

An AI agent can call code_attach faster than any human can review — one bad instruction and it creates or modifies resources in Yaver by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

code_attach Rate-limited

code_attach stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "code_attach": {
      "limits": [
        {
          "counter": "code_attach_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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 code_attach

What does the code_attach tool do? +

Attach yaver code to a machine so the repo/files and coding context live there while the terminal stays local. Returns the selected machine, runner summary, target context, and updated code config. Optional device_id mutates another owned Yaver machine's code control plane instead of this one. It is categorised as a Write tool in the Yaver MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does code_attach accept? +

code_attach accepts 3 parameters: target, username, device_id. Required: target. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on code_attach? +

Register the Yaver MCP server in PolicyLayer and add a rule for code_attach: 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 code_attach? +

code_attach is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit code_attach? +

Yes. Add a rate_limit block to the code_attach 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 code_attach completely? +

Set action: deny in the PolicyLayer policy for code_attach. 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 code_attach? +

code_attach 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.