hippo_corpus_diff
FORGIA #218 — timeline of changes across the 3 memory
This record as markdown: /tools/verimem/hippo-corpus-diff.md
What hippo_corpus_diff does on Verimem
AI agents call hippo_corpus_diff to retrieve information from Verimem without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why hippo_corpus_diff is rated Low
This tool retrieves a timeline or audit trail of memory changes rather than creating, executing code, destroying data, or moving money. While access to change histories could expose sensitive patterns in what has been modified (moderate information disclosure risk), the operation itself is fundamentally a read/query function.
From the tool's definition Tool name 'hippo_corpus_diff' and description 'timeline of changes across the 3 memory' indicate querying/retrieving historical change data.
Attacks that exploit this kind of access
The rule that runs hippo_corpus_diff safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Verimem, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For hippo_corpus_diff, this is the rule to start with:
hippo_corpus_diff is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Verimem, apply this rule, and every hippo_corpus_diff call is checked against it from then on.
Questions about hippo_corpus_diff
FORGIA #218 — timeline of changes across the 3 memory. It is categorised as a Read tool in the Verimem MCP Server, which means it retrieves data without modifying state.
Register the Verimem MCP server in PolicyLayer and add a rule for hippo_corpus_diff: 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 Verimem. Nothing to install.
hippo_corpus_diff 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 hippo_corpus_diff 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 hippo_corpus_diff. 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.
hippo_corpus_diff is provided by the Verimem MCP server (aureliocpr-ctrl/verimem). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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