Find documents that both docA and docB are connected to (shared neighbors). Returns enriched entries with relationship types.
AI agents call knowledge_common to retrieve information from Ralph Hero without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries existing document connections and returns data without creating, modifying, deleting, or executing anything. It is a straightforward read operation that retrieves relationship metadata between documents. No side effects or state changes occur.
From the tool's definition Tool description states it 'Find documents' and 'Returns enriched entries' — pure retrieval operations with no modification, deletion, or execution. The phrase 'shared neighbors' indicates a query/search operation across existing relationships.
Attacks that exploit this kind of access
Find documents that both docA and docB are connected to (shared neighbors). Returns enriched entries with relationship types. It is categorised as a Read tool in the Ralph Hero MCP Server, which means it retrieves data without modifying state.
Register the Ralph Hero MCP server in PolicyLayer and add a rule for knowledge_common: 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 Ralph Hero. Nothing to install.
knowledge_common is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the knowledge_common 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.
Set action: deny in the PolicyLayer policy for knowledge_common. 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.
knowledge_common is provided by the Ralph Hero MCP server (ralph-hero-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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