AI agents call check_freshness to retrieve information from Brain without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only comparison operation that retrieves and analyzes file state to determine if cached knowledge remains current. It requires file system access but performs no writes, deletions, or external executions. The operation is informational—it reports staleness without side effects. Requires local repo path but only to read files for comparison.
From the tool's definition Tool checks/compares referenced files against stored knowledge state, returning freshness status without modifying data. 'Check whether' and 'comparing' indicate read-only inspection operations.
Attacks that exploit this kind of access
Check whether code-linked knowledge is still fresh by comparing referenced files against their state when knowledge was captured. Requires the local repo checkout path. It is categorised as a Read tool in the Brain MCP Server, which means it retrieves data without modifying state.
Register the Brain MCP server in PolicyLayer and add a rule for check_freshness: 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 Brain. Nothing to install.
check_freshness 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 check_freshness 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 check_freshness. 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.
check_freshness is provided by the Brain MCP server (markschaake/brain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
check_freshness is one line of Brain's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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