bbs_set_context · Mcp Bbs MCP: Risk & Policy

WHAT IT DOES

What bbs_set_context does on Mcp Bbs

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

WHY IT NEEDS A POLICY

Why bbs_set_context needs a policy

The tool creates or modifies data (context entries in JSONL logs) in a reversible manner. While logging is typically not user-facing application data, writing to logs can affect audit trails, debugging information, and system behavior.

From the tool's definition Tool description states it 'Set structured context that is embedded in JSONL logs' — this modifies log data by writing structured context entries.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

bbs_set_context Rate-limited

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

FAQ

Questions about bbs_set_context

What does the bbs_set_context tool do? +

Set structured context that is embedded in JSONL logs. It is categorised as a Write tool in the Mcp Bbs MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on bbs_set_context? +

Register the Mcp Bbs MCP server in PolicyLayer and add a rule for bbs_set_context: 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 bbs_set_context? +

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

Can I rate-limit bbs_set_context? +

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

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

bbs_set_context 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.