Retrieves custom data entries by exact category and/or key lookup. Provide category alone to list all entries in that category, or both category+key for a specific entry. Omit both to list all custom data. For keyword search across custom data values, use search_custom_data_value_fts. For glossar...
AI agents call get_custom_data to retrieve information from Engrams without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool purely retrieves and queries persistent memory data without side effects. It allows lookups by category and key, listing entries, and searching values—all read-only operations. No data is created, modified, deleted, or executed.
From the tool's definition Tool description states it 'Retrieves custom data entries' and 'Returns' data structures. Keywords: 'lookup', 'list', 'search' indicate query-only operations with no modification, deletion, or execution capabilities.
Documented attack patterns abuse exactly the kind of access get_custom_data gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Engrams, and nothing reaches the server without passing your rules. This is the rule we recommend for get_custom_data:
{
"version": "1",
"default": "deny",
"tools": {
"get_custom_data": {}
}
}get_custom_data is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Retrieves custom data entries by exact category and/or key lookup. Provide category alone to list all entries in that category, or both category+key for a specific entry. Omit both to list all custom data. For keyword search across custom data values, use search_custom_data_value_fts. For glossary-specific search, use search_project_glossary_fts. Returns: [{category, key, value, created_at, ...}]. It is categorised as a Read tool in the Engrams MCP Server, which means it retrieves data without modifying state.
Register the Engrams MCP server in PolicyLayer and add a rule for get_custom_data: 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 Engrams. Nothing to install.
get_custom_data 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_custom_data 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_custom_data. 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_custom_data is provided by the Engrams MCP server (stevebrownlee/engrams). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Engrams, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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42 Engrams tools catalogued and risk-classified — across an index of 43,000+ MCP servers.