> ## Documentation Index
> Fetch the complete documentation index at: https://www.docs.forgeshipyard.com/llms.txt
> Use this file to discover all available pages before exploring further.

# L6 · Verification Ladder

> The ordered set of checks every output passes before it can become a decision.

export const VerificationLadder = () => <Tooltip tip="The ordered sequence of checks that runs on every AI output before it can become an authoritative decision, ending in human sign-off when required.">verification ladder</Tooltip>;

<Note>
  **In plain terms:** Before any AI output becomes a real decision, it climbs a ladder
  of checks. Automatic checks establish the sources, applicability, confidence, and
  geometry evidence first. Responsible engineers and external authorities enter where
  the decision requires them, and the final approved result is signed and recorded.
</Note>

## What it does

L6 applies cost-asymmetric checks in order. "Cost-asymmetric" means the fast,
deterministic checks run first. Reviews that require an engineer, class society, or
regulator enter later, after the evidence has already been checked. This protects
specialist review time while preserving human authority. This is the
<VerificationLadder />.

## The gates, in order

| Gate   | Question it asks                                                  | In plain terms                              |
| ------ | ----------------------------------------------------------------- | ------------------------------------------- |
| **T1** | Does every material claim cite a source or evidence object?       | Show the basis for the claim                |
| **T2** | Is the rule applicable to this vessel context?                    | Confirm that the right rule is being used   |
| **T3** | Are assumptions explicit and confidence usable?                   | Make uncertainty visible                    |
| **T4** | Does every numeric geometry claim cite a real measurement record? | Attach every number to engineering evidence |
| **T5** | Does the responsible engineer approve or reject the proposal?     | Human engineering review                    |
| **T6** | Is class or USCG review required, and has it occurred?            | External-authority review where applicable  |
| **T7** | Is the approved decision signed and recorded?                     | Create the final accountable record         |

## Where human authority enters

High-risk engineering decisions reach responsible-engineer review at T5.
Class-touching or USCG-touching decisions also carry the T6 external-review
requirement. T7 signs and records the approved result. These requirements are part of
the decision path, not optional interface settings.

## If a gate fails

If any gate fails, the proposal does not become a decision. The failure is logged
with its reason, and the engineer sees exactly what is missing. Nothing
half-verified slips through.

## What L6 outputs

* `verification_result`
* `review_task`
* `signed_decision`

Once a proposal clears the ladder (including human sign-off where required), it
becomes a signed decision in the [Decision Ledger](/how-it-works/layers/l2-5-decision-ledger).
See [How a Decision Gets Made](/concepts/how-a-decision-gets-made) for the full
walkthrough.