<!--
{
  "availability" : [
    "iOS: 27.0.0 -",
    "iPadOS: 27.0.0 -",
    "macCatalyst: 27.0.0 -",
    "macOS: 27.0.0 -",
    "visionOS: 27.0.0 -",
    "watchOS: 27.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "FoundationModels",
  "identifier" : "/documentation/FoundationModels/LanguageModelExecutorGenerationChannel/ReasoningSignature",
  "metadataVersion" : "0.1.0",
  "role" : "Structure",
  "symbol" : {
    "kind" : "Structure",
    "modules" : [
      "Foundation Models",
      "FoundationModels"
    ],
    "preciseIdentifier" : "s:16FoundationModels38LanguageModelExecutorGenerationChannelV18ReasoningSignatureV"
  },
  "title" : "LanguageModelExecutorGenerationChannel.ReasoningSignature"
}
-->

# LanguageModelExecutorGenerationChannel.ReasoningSignature

Payload for a reasoning entry’s signature update.

```
struct ReasoningSignature
```

## Overview

The signature is an opaque, producer-supplied token; each `updateSignature` event replaces
the prior value wholesale. `tokenCount` is the producer’s count of tokens carried by the
signature, used for usage accounting.

## Topics

### Handling the reasoning signature

[`var signature: Data`](/documentation/FoundationModels/LanguageModelExecutorGenerationChannel/ReasoningSignature/signature)

The opaque token that authenticates the reasoning entry.

[`var tokenCount: Int`](/documentation/FoundationModels/LanguageModelExecutorGenerationChannel/ReasoningSignature/tokenCount)

The number of the tokens the signature carries.

## Relationships

### Conforms To

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Sendable`](/documentation/Swift/Sendable)

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)