# validate_checkpoint

Before you resume a crashed job, check that the checkpoint you are about to resume FROM is not the one the crash corrupted. Give it ls -la of the checkpoint directory, and optionally sha256sum -c output and any load errors. Returns which checkpoints are valid, which are corrupt, and the newest safe resume point. Resuming from a mid-write checkpoint costs days and is the single most expensive avoidable mistake after a crash.

Agent View of the PolicyLayer registry record for `validate_checkpoint`. HTML page: https://policylayer.com/tools/denpex-mcp/validate-checkpoint

## Facts

- Tool: `validate_checkpoint`
- Server: Denpex (`denpex-mcp`) — https://policylayer.com/tools/denpex-mcp.md
- Install: `npx -y denpex-mcp`
- Homepage: https://www.npmjs.com/package/denpex-mcp
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 4
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `loadErrors` | string | no | Any error output from trying to load a checkpoint. |
| `failureType` | string | no | The diagnosed failure type, if you have one — it sharpens the verdict. |
| `sha256Output` | string | no | Output of `sha256sum -c MANIFEST.sha256`, if you keep a manifest. |
| `directoryListing` | string | no | Output of `ls -la` (or `ls -la --time-style=full-iso`) on the checkpoint directory. |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "validate_checkpoint",
    "arguments": {}
  }
}
```

## Why validate_checkpoint is rated Low

Even though validate_checkpoint 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.

## Use case

AI agents call validate_checkpoint 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.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Denpex:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "validate_checkpoint": {}
  }
}
```

## Other tools on Denpex (14)

- `compare_runs` — Execute — https://policylayer.com/tools/denpex-mcp/compare-runs.md
- `diff_environments` — Execute — https://policylayer.com/tools/denpex-mcp/diff-environments.md
- `node_health` — Execute — https://policylayer.com/tools/denpex-mcp/node-health.md
- `predict_failures` — Execute — https://policylayer.com/tools/denpex-mcp/predict-failures.md
- `analyze_cascade` — Read — https://policylayer.com/tools/denpex-mcp/analyze-cascade.md
- `ask_followup` — Read — https://policylayer.com/tools/denpex-mcp/ask-followup.md
- `check_quota` — Read — https://policylayer.com/tools/denpex-mcp/check-quota.md
- `check_versions` — Read — https://policylayer.com/tools/denpex-mcp/check-versions.md
- `diagnose_crash` — Read — https://policylayer.com/tools/denpex-mcp/diagnose-crash.md
- `list_incidents` — Read — https://policylayer.com/tools/denpex-mcp/list-incidents.md
- `lookup_failure` — Read — https://policylayer.com/tools/denpex-mcp/lookup-failure.md
- `preflight_check` — Read — https://policylayer.com/tools/denpex-mcp/preflight-check.md
- `recent_diagnoses` — Read — https://policylayer.com/tools/denpex-mcp/recent-diagnoses.md
- `submit_fix_outcome` — Write — https://policylayer.com/tools/denpex-mcp/submit-fix-outcome.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=denpex-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/denpex-mcp