NeuralTrust | The leading security platform for generative AI

Every inspection goes through one runtime endpoint, POST /v1/guard. This page explains what happens between the request and the verdict.

1. Authenticate and resolve the collector

The caller sends Authorization: Bearer <api-key>. TrustGuard verifies the key, checks it is active and not expired, and resolves the collector it belongs to. The collector is never sent in the request body — it comes from the key. A missing or invalid key returns 401; an inactive/expired key is rejected before any evaluation runs.

2. Resolve the policy

TrustGuard picks the policy for this request:

if the request’s consumer_id has a per‑consumer policy, use it;
otherwise use the collector’s default policy.

If the collector has no matching policy, the request is unguarded: TrustGuard returns status: "allow" with no findings. The policy’s Enforcement mode (Report vs Enforce) is read here — in Report mode every action below is downgraded to a non‑blocking record.

3. Run gates

Gates are evaluated before any detector. Each gate matches request attributes (consumer, model, collector, protocol, session) and takes an action:

Gate action	Effect
Block	The request is blocked and detectors are skipped. Returns `status: "block"`.
Report	Records a finding and continues to detection.
Skip	Stops gate evaluation and proceeds to detection — no finding.

All gates are evaluated and the most restrictive outcome wins.

4. Run the detector rules

For the request’s direction (input or output), TrustGuard runs the policy’s matching detector rules. Rules are filtered by direction and by their optional conditions, then split by capability:

Phase	Detectors	Execution
Detect	Every detection‑only detector	Run concurrently; results merged deterministically. They read the payload but never modify it.
Transform	Mutable detectors (today `data_loss_prevention`)	Run sequentially after detection. With the Transform action they rewrite the payload, producing `transformed_payload`.

Each rule’s action — Monitor (report), Block, or Transform — sets the outcome.action on the findings it produces. A block rule also stops the remaining detector chain. File attachments (payload.attachments) are decoded once and shared with the detectors that consume them (doc_analyzer, url_analyzer). Remote attachment URLs are fetched server‑side under a strict SSRF guard (HTTPS only; loopback, private, link‑local, CGNAT, and cloud‑metadata addresses blocked) and are never stored.

5. Reduce to a status

Everything that fired is reduced to one top‑level status, most to least restrictive:

block  →  transform  →  report  →  allow

In Report mode, blocks and transforms are downgraded, so the status never exceeds report.

6. The response

{
  "status": "transform",
  "transformed_payload": { "input": "My email is [MASKED_EMAIL]" },
  "findings": [
    {
      "source": { "kind": "detector", "plugin": "data_loss_prevention", "detector_name": "PII masking", "policy_id": "…" },
      "signal": { "type": "pii", "confidence": 1.0 },
      "outcome": { "action": "transform" },
      "evidence": { "masked": 1, "entities": ["email"] }
    }
  ],
  "trace_id": "f1e2…",
  "request_id": "a9b8…"
}

Field	Meaning
`status`	`allow` · `report` · `transform` · `block` — the reduced verdict. Advisory: the caller enforces.
`transformed_payload`	The rewritten payload, or absent/`null` if no Transform rule changed anything.
`findings[]`	One entry per gate or detector that fired. See the Guard API for the full shape.
`trace_id` / `request_id`	Correlation IDs propagated through logs and telemetry.

A detection is always HTTP 200 — including a block status. Your integration acts on status / findings; it never relies on TrustGuard to reject the request.

Failure behavior

If a detector hits an infrastructure error (an upstream provider is down, a timeout, etc.), behavior follows your deployment’s fail‑open / fail‑closed setting:

Fail‑open — TrustGuard drops that detector’s result and the request still succeeds, so a TrustGuard issue never breaks your traffic.
Fail‑closed — the request returns 500 so the caller can decide to hold traffic.

A structured block decision (from a gate or a Block rule) always applies regardless of this setting. Ask NeuralTrust about the setting for your deployment.

​1. Authenticate and resolve the collector

​2. Resolve the policy

​3. Run gates

​4. Run the detector rules

​5. Reduce to a status

​6. The response

​Failure behavior