lookup_failure
Search Denpex's bundled failure encyclopedia by error code, keyword, or symptom (e.g. 'Xid 79', 'NCCL timeout', 'loss is NaN', 'CUDA out of memory'). Returns the most relevant known failures with their fixes. Works fully offline and costs no quota — but the BUNDLE is a subset: 312 classes on-host...
This record as markdown: /tools/denpex-mcp/lookup-failure.md
What lookup_failure does on Denpex
AI agents call lookup_failure to retrieve information from Denpex without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
limit | integer | — | Max results (default 5). |
query | string | Yes | Error code, message, or symptom to look up. |
Parameters from the server's own tool schema.
Why lookup_failure is rated Low
Even though lookup_failure only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs lookup_failure safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Denpex, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For lookup_failure, this is the rule to start with:
lookup_failure 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 Denpex, apply this rule, and every lookup_failure call is checked against it from then on.
Questions about lookup_failure
Search Denpex's bundled failure encyclopedia by error code, keyword, or symptom (e.g. 'Xid 79', 'NCCL timeout', 'loss is NaN', 'CUDA out of memory'). Returns the most relevant known failures with their fixes. Works fully offline and costs no quota — but the BUNDLE is a subset: 312 classes on-host against the full corpus the cloud ranks. Use diagnose_crash instead when you have a full crash log. It is categorised as a Read tool in the Denpex MCP Server, which means it retrieves data without modifying state.
lookup_failure accepts 2 parameters: limit, query. Required: query. The full parameter table on this page comes from the server's own tool schema.
Register the Denpex MCP server in PolicyLayer and add a rule for lookup_failure: 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 Denpex. Nothing to install.
lookup_failure 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 lookup_failure 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 lookup_failure. 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.
lookup_failure is provided by the Denpex MCP server (denpex-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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