AI agents call get_spellbook_file_content to retrieve information from Dune without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves file content from a GitHub repository (Dune's Spellbook). Fetching content is a read-only operation that queries data without modifying, deleting, or executing anything. The blast radius of misuse is minimal—an agent could retrieve sensitive or private file content if permissions allow, but cannot modify or delete it. Classified as Read with low severity.
From the tool's definition Tool name includes 'get_' and description states 'Fetch raw content' from GitHub, indicating a retrieval operation with no side effects.
Attacks that exploit this kind of access
Fetch raw content of a Spellbook file from GitHub. It is categorised as a Read tool in the Dune MCP Server, which means it retrieves data without modifying state.
Register the Dune MCP server in PolicyLayer and add a rule for get_spellbook_file_content: 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 Dune. Nothing to install.
get_spellbook_file_content 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 get_spellbook_file_content 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 get_spellbook_file_content. 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.
get_spellbook_file_content is provided by the Dune MCP server (nice-bills/dune-mcp). 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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