diff --git a/Package.swift b/Package.swift
index 3a36f13..13b426a 100644
--- a/Package.swift
+++ b/Package.swift
@@ -20,7 +20,7 @@ let package = Package(
         .library(name: "SwiftAgentKitMac", targets: ["SwiftAgentKitMac"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/ayman3000/LLMProviderKit.git", from: "0.1.0-alpha.42"),
+        .package(url: "https://github.com/ayman3000/LLMProviderKit.git", from: "0.1.0-alpha.43"),
         .package(url: "https://github.com/swiftlang/swift-syntax.git", from: "603.0.0"),
         .package(url: "https://github.com/modelcontextprotocol/swift-sdk.git", from: "0.12.1"),
         .package(url: "https://github.com/swiftlang/swift-docc-plugin.git", from: "1.4.0"),
diff --git a/Sources/SwiftAgentKit/Core/AgentLLMResponse.swift b/Sources/SwiftAgentKit/Core/AgentLLMResponse.swift
index 7908057..bdf6f61 100644
--- a/Sources/SwiftAgentKit/Core/AgentLLMResponse.swift
+++ b/Sources/SwiftAgentKit/Core/AgentLLMResponse.swift
@@ -126,12 +126,17 @@ public struct AgentTokenUsage: Sendable, Equatable {
     /// Prompt tokens served from the provider's prompt cache (subset of
     /// promptTokens); nil when the provider didn't report it.
     public let cachedTokens: Int?
+    /// Prompt tokens written into the provider's cache (Anthropic), billed
+    /// above plain input; nil when the provider didn't report it.
+    public let cacheWriteTokens: Int?
 
-    public init(promptTokens: Int?, completionTokens: Int?, totalTokens: Int?, cachedTokens: Int? = nil) {
+    public init(promptTokens: Int?, completionTokens: Int?, totalTokens: Int?, cachedTokens: Int? = nil,
+                cacheWriteTokens: Int? = nil) {
         self.promptTokens = promptTokens
         self.completionTokens = completionTokens
         self.totalTokens = totalTokens
         self.cachedTokens = cachedTokens
+        self.cacheWriteTokens = cacheWriteTokens
     }
 
     public static func from(_ usage: LLMUsage?) -> AgentTokenUsage? {
@@ -140,7 +145,8 @@ public struct AgentTokenUsage: Sendable, Equatable {
             promptTokens: usage.promptTokens,
             completionTokens: usage.completionTokens,
             totalTokens: usage.totalTokens,
-            cachedTokens: usage.cachedTokens
+            cachedTokens: usage.cachedTokens,
+            cacheWriteTokens: usage.cacheWriteTokens
         )
     }
 }
diff --git a/Tests/SwiftAgentKitReplayTests/StreamingUsageTests.swift b/Tests/SwiftAgentKitReplayTests/StreamingUsageTests.swift
index 7d62924..a49edec 100644
--- a/Tests/SwiftAgentKitReplayTests/StreamingUsageTests.swift
+++ b/Tests/SwiftAgentKitReplayTests/StreamingUsageTests.swift
@@ -28,3 +28,13 @@ import SwiftAgentKit
     #expect(usage?.promptTokens == 123)
     #expect(usage?.completionTokens == 45)
 }
+
+/// Cache writes (Anthropic) reach the host apart from reads, so it can price
+/// them at their own rate.
+@Test func usageCarriesCacheWritesFromTheProvider() {
+    let u = AgentTokenUsage.from(LLMUsage(promptTokens: 990, completionTokens: 3, totalTokens: 993,
+                                          cachedTokens: 900, cacheWriteTokens: 40))
+    #expect(u?.cachedTokens == 900)
+    #expect(u?.cacheWriteTokens == 40)
+    #expect(AgentTokenUsage.from(LLMUsage(promptTokens: 5))?.cacheWriteTokens == nil)
+}