pin_fact · Prompt Architect MCP: Risk & Policy

WHAT IT DOES

What pin_fact does on Prompt Architect

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

WHY IT NEEDS A POLICY

Why pin_fact needs a policy

This tool creates or modifies project context by storing facts for inclusion in prompts. It is reversible (facts can be unpinned or modified), involves no deletion or external operations, and has minimal blast radius if misused—an AI agent could only add potentially misleading facts to its own project context. This is a Write operation with low severity since the scope is limited to local context management.

From the tool's definition Tool name 'pin_fact' and description 'Pin an important fact to always include in your project context' indicate creating or modifying stored context data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pin_fact Rate-limited

pin_fact 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": {
    "pin_fact": {
      "limits": [
        {
          "counter": "pin_fact_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 Prompt Architect, so you can run agents against it safely.

FAQ

Questions about pin_fact

What does the pin_fact tool do? +

Pin an important fact to always include in your project context. It is categorised as a Write tool in the Prompt Architect MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on pin_fact? +

Register the Prompt Architect MCP server in PolicyLayer and add a rule for pin_fact: 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 Prompt Architect. Nothing to install.

What risk level is pin_fact? +

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

Can I rate-limit pin_fact? +

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

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

pin_fact is provided by the Prompt Architect MCP server (prompt-architect-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.