Search patterns (HNSW)
AI agents call pattern_search to retrieve information from Claude Flow without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a search query operation against a pattern database or vector index. No side effects, modifications, deletions, code execution, or financial operations are indicated. It is a read-only retrieval function, similar to a semantic search or similarity lookup. Severity is low because even if abused by an agent, it can only retrieve existing data without changing state or triggering external operations.
From the tool's definition Tool name is 'pattern_search' and description states 'Search patterns (HNSW)', where HNSW refers to Hierarchical Navigable Small World, a vector similarity search algorithm.
Attacks that exploit this kind of access
Search patterns (HNSW). It is categorised as a Read tool in the Claude Flow MCP Server, which means it retrieves data without modifying state.
Register the Claude Flow MCP server in PolicyLayer and add a rule for pattern_search: 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 Claude Flow. Nothing to install.
pattern_search 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 pattern_search 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 pattern_search. 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.
pattern_search is provided by the Claude Flow MCP server (claude-flow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.