preflight_check
Answer 'is this cluster safe to launch on?' BEFORE you burn GPU-hours on a job that will die in the first ten minutes. Feed it the health artifacts from the nodes you are about to use — nvidia-smi -q, ibstat, nvidia-smi topo -m, dmesg -T — and it returns the critical blockers (dead links, missing...
This record as markdown: /tools/denpex-mcp/preflight-check.md
What preflight_check does on Denpex
AI agents call preflight_check 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 |
|---|---|---|---|
dir | string | — | Directory to scan for the newest artifact file. |
file | string | — | Path to a file containing them. |
logs | string | — | Paste the health artifacts (nvidia-smi -q, ibstat, nvidia-smi topo -m, dmesg -T). |
Parameters from the server's own tool schema.
Why preflight_check is rated Low
Even though preflight_check 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.
Risk signalsAccepts file system path (file)
Attacks that exploit this kind of access
The rule that runs preflight_check 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 preflight_check, this is the rule to start with:
preflight_check 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 preflight_check call is checked against it from then on.
Questions about preflight_check
Answer 'is this cluster safe to launch on?' BEFORE you burn GPU-hours on a job that will die in the first ten minutes. Feed it the health artifacts from the nodes you are about to use — nvidia-smi -q, ibstat, nvidia-smi topo -m, dmesg -T — and it returns the critical blockers (dead links, missing GPUs, non-NVLink topology, driver mismatch) that would take the run down. Scale+ feature. It is categorised as a Read tool in the Denpex MCP Server, which means it retrieves data without modifying state.
preflight_check accepts 3 parameters: dir, file, logs. 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 preflight_check: 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.
preflight_check 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 preflight_check 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 preflight_check. 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.
preflight_check 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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