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

# ward fuzz <id>

> Run one invariant in isolation with full, verbose evidence output.

## Usage

```bash theme={null}
ward fuzz A1
ward fuzz u2   # ids are case-insensitive — normalized to uppercase internally
# or, from source:
npm run ward -- fuzz A1
```

## What it does

Runs a single invariant end to end, in `debug` log level, and prints:

1. The invariant's id, name, `source` citation, and category.
2. A `PASS`/`FAIL` badge and duration.
3. Its `evidenceSummary` — the same one-line summary `ward test`'s table shows.
4. The **full** `evidence` object, pretty-printed as JSON — every request sent and response
   received for every sub-case, unredacted.

This is the fastest way to see exactly what payload Ward built, exactly what mutation was applied,
and exactly how the facilitator responded — the detail `ward test`'s compact table intentionally
leaves out.

## Valid invariant ids

`U1`, `U2`, `U3`, `U4`, `U5`, `A1`, `A2`, `A3` — see the full [Invariants Overview](/invariants/overview).

## Example output

```
$ ward fuzz A1

Fuzzing A1 — atomic group integrity
Algorand atomic transaction groups (protocol primitive) + @x402/avm facilitator's
verifyFeePayerTransaction; USENIX Security '26 study — Free Shopping, Asset Theft,
Service Denial, Gas Abuse
category: algorand

Result: PASS (2143ms)
fee-payer leg amount > 0 (drains value instead of a pure self-payment): OK;
fee-payer leg receiver redirected away from self: OK;
fee-payer leg closes remainder balance to a third party: OK;
fee-payer leg rekeys the facilitator's own account: OK;
fee-payer leg fee inflated far past the reasonable cap: OK

--- evidence ---
{
  "baselineTransaction": "ABCD1234...",
  "subResults": [ ... ],
  "evidence": [
    { "label": "GET /supported (discovering fee-payer address)", "request": null, "response": { ... } },
    { "label": "baseline sponsored-fee settle (sanity check)", "request": { ... }, "response": { ... } },
    { "label": "verify — fee-payer leg amount > 0 ...", "request": { "original": { ... }, "tampered": { ... } }, "response": { ... } }
  ]
}
```

## Exit code

Exits non-zero if the invariant failed — useful for scripting a one-off check without running the
whole suite, e.g. in a bisecting workflow while debugging a facilitator change.

<Card title="Re-render a full past run" icon="table" href="/cli/report" horizontal />