Fields \u00b7 query greymatterFields. Variables: after, filter, first, order. Example variables: {\
AI agents call greymatter_fields to retrieve information from ReliaQuest GreyMatter MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries fields metadata from the GreyMatter platform without modifying data. The use of pagination (after, first), filtering, and ordering parameters indicates a read-only retrieval operation. No side effects or data mutations are described. Classification as Read is appropriate with low severity since it only retrieves information about available fields.
From the tool's definition Tool name 'greymatter_fields' with description indicating it 'query greymatterFields' with query parameters (after, filter, first, order) typical of GraphQL read operations.
Attacks that exploit this kind of access
Fields \u00b7 query greymatterFields. Variables: after, filter, first, order. Example variables: {\. It is categorised as a Read tool in the ReliaQuest GreyMatter MCP Server MCP Server, which means it retrieves data without modifying state.
Register the ReliaQuest GreyMatter MCP Server MCP server in PolicyLayer and add a rule for greymatter_fields: 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 ReliaQuest GreyMatter MCP Server. Nothing to install.
greymatter_fields 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 greymatter_fields 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 greymatter_fields. 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.
greymatter_fields is provided by the ReliaQuest GreyMatter MCP Server MCP server (space-c0wboy/reliaquest-greymatter-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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