AI agents call describe_field to retrieve information from Mcp Svd without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves structured data about ARM microcontroller register bit-fields from SVD definitions. It has no side effects—it only returns informational metadata to help developers understand hardware registers. The use case is clearly informational ('prevent hallucinations during embedded systems development'), making it a Read category tool with low severity and high confidence.
From the tool's definition The tool 'describe_field' retrieves information about bit-field properties: 'bit offset, width, access type, and enumerated values'. The description uses passive language ('Describe', 'understand') focused on querying hardware register metadata.
Attacks that exploit this kind of access
Describe a specific bit-field within a register: its bit offset, width, access type, and enumerated values if defined. Use this when you need to understand or set a specific control bit or flag. It is categorised as a Read tool in the Mcp Svd MCP Server, which means it retrieves data without modifying state.
Register the Mcp Svd MCP server in PolicyLayer and add a rule for describe_field: 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 Svd. Nothing to install.
describe_field 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 describe_field 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 describe_field. 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.
describe_field is provided by the Mcp Svd MCP server (pkt-lab/mcp-svd). 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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