---
url: >-
  https://adk.nht.io/api/@nhtio/adk/batteries/llm/openai_responses/variables/defaultCanonicalFingerprint.md
description: >-
  Default canonical-fingerprint primitive; alias of {@link
  canonicalFingerprint}.
---

# Variable: defaultCanonicalFingerprint

```ts
const defaultCanonicalFingerprint: (value: unknown) => Promise<string> =
  canonicalFingerprint;
```

Defined in: [src/batteries/llm/chat\_common/helpers.ts:973](https://github.com/NHTIO/ADK/blob/v1.20260901.0/src/src/batteries/llm/chat_common/helpers.ts#L973)

Default canonical-fingerprint primitive; alias of [canonicalFingerprint](../functions/canonicalFingerprint.md).

Computes a SHA-256 fingerprint of `value` via canonical canonicalisation, over its UTF-8
bytes, using `globalThis.crypto.subtle.digest`.

## Parameters

| Parameter | Type      |
| --------- | --------- |
| `value`   | `unknown` |

## Returns

`Promise`<`string`>

## Remarks

Wire-shape-agnostic replay-prefix fingerprinting primitive shared across the Chat-family LLM
batteries' "reasoning replay" features (Anthropic's signed `thinking` blocks, and any sibling
battery's equivalent). Each battery assembles its own wire-shaped prefix object — e.g. `{ model,
system, tools, messages }` for Anthropic Messages — and passes it here; this primitive carries no
knowledge of any individual wire shape.