AI agents call list_spaces to retrieve information from Ai Brain without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves metadata about workspaces and user permissions without creating, modifying, or deleting any data. It is a straightforward enumeration endpoint used to discover available resources, posing minimal risk even if misused by an agent, as it only exposes information the authenticated user already has access to.
From the tool's definition Tool name 'list_spaces' and description 'List the spaces (workspaces) the user can access' indicate a retrieval operation with no side effects.
Attacks that exploit this kind of access
List the spaces (workspaces) the user can access, with their role in each. Most tools require a space_id from here. It is categorised as a Read tool in the Ai Brain MCP Server, which means it retrieves data without modifying state.
Register the Ai Brain MCP server in PolicyLayer and add a rule for list_spaces: 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 Ai Brain. Nothing to install.
list_spaces 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 list_spaces 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 list_spaces. 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.
list_spaces is provided by the Ai Brain MCP server (thejoshgriffith/ai-brain). 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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