hijack_step · Mcp Bbs MCP: Risk & Policy

WHAT IT DOES

What hijack_step does on Mcp Bbs

AI agents invoke hijack_step to trigger actions in Mcp Bbs. 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.

WHY IT NEEDS A POLICY

Why hijack_step needs a policy

The tool executes a step in a bot loop that has been 'hijacked' (taken over via assume_bot). This constitutes running/triggering external operations on a remote BBS system. The word 'hijacked' implies control over an automated process, and stepping it executes whatever that bot loop does next. Severity is high because misuse could cause unintended actions on remote systems or other users' sessions.

From the tool's definition 'Single-step a hijacked bot loop' — triggers execution of a step within a hijacked/assumed bot process

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

hijack_step Rate-limited

hijack_step 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": {
    "hijack_step": {
      "limits": [
        {
          "counter": "hijack_step_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 Mcp Bbs, so you can run agents against it safely.

FAQ

Questions about hijack_step

What does the hijack_step tool do? +

Single-step a hijacked bot loop. It is categorised as a Execute tool in the Mcp Bbs MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on hijack_step? +

Register the Mcp Bbs MCP server in PolicyLayer and add a rule for hijack_step: 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 Mcp Bbs. Nothing to install.

What risk level is hijack_step? +

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

Can I rate-limit hijack_step? +

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

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

hijack_step is provided by the Mcp Bbs MCP server (livingstaccato/mcp-bbs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.