From 1f63555ef178e750f6571d15bee55718b9cc49b4 Mon Sep 17 00:00:00 2001
From: Dylan Pulver <dylanpulver@users.noreply.github.com>
Date: Wed, 19 Aug 2026 17:05:38 +0300
Subject: [PATCH 1/4] fix(anthropic): Record
 output_tokens_details.thinking_tokens as completion_thinking_tokens

---
 .../anthropic-thinking-tokens-metric.md       |  5 ++
 ...anthropic-v0-latest-wrapped.span-tree.json |  1 +
 .../anthropic-v0-latest-wrapped.span-tree.txt |  1 +
 .../anthropic-v0-latest.span-tree.json        |  1 +
 .../anthropic-v0-latest.span-tree.txt         |  1 +
 .../anthropic-instrumentation/assertions.ts   | 12 ++++
 .../plugins/anthropic-plugin.test.ts          | 72 +++++++++++++++++++
 .../plugins/anthropic-plugin.ts               | 12 ++++
 js/src/vendor-sdk-types/anthropic.ts          | 11 +++
 9 files changed, 116 insertions(+)
 create mode 100644 .changeset/anthropic-thinking-tokens-metric.md

diff --git a/.changeset/anthropic-thinking-tokens-metric.md b/.changeset/anthropic-thinking-tokens-metric.md
new file mode 100644
index 000000000..74949c1c0
--- /dev/null
+++ b/.changeset/anthropic-thinking-tokens-metric.md
@@ -0,0 +1,5 @@
+---
+"braintrust": patch
+---
+
+fix(anthropic): Record `output_tokens_details.thinking_tokens` as `completion_thinking_tokens`
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json
index 1a4e1fd9c..fdcd2d7b8 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json
@@ -646,6 +646,7 @@
                 }
               },
               "metrics": {
+                "completion_thinking_tokens": 42,
                 "completion_tokens": 48,
                 "prompt_cache_creation_1h_tokens": 0,
                 "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt
index f9d451a62..927553ccd 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt
@@ -573,6 +573,7 @@ span_tree:
     │         }
     │       }
     │       metrics: {
+    │         "completion_thinking_tokens": 42,
     │         "completion_tokens": 48,
     │         "prompt_cache_creation_1h_tokens": 0,
     │         "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json
index 1a4e1fd9c..fdcd2d7b8 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json
@@ -646,6 +646,7 @@
                 }
               },
               "metrics": {
+                "completion_thinking_tokens": 42,
                 "completion_tokens": 48,
                 "prompt_cache_creation_1h_tokens": 0,
                 "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt
index f9d451a62..927553ccd 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt
@@ -573,6 +573,7 @@ span_tree:
     │         }
     │       }
     │       metrics: {
+    │         "completion_thinking_tokens": 42,
     │         "completion_tokens": 48,
     │         "prompt_cache_creation_1h_tokens": 0,
     │         "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/assertions.ts b/e2e/scenarios/anthropic-instrumentation/assertions.ts
index 28499330c..ea7bdaa21 100644
--- a/e2e/scenarios/anthropic-instrumentation/assertions.ts
+++ b/e2e/scenarios/anthropic-instrumentation/assertions.ts
@@ -747,6 +747,18 @@ export function defineAnthropicInstrumentationAssertions(options: {
           prompt_tokens: expect.any(Number),
           completion_tokens: expect.any(Number),
         });
+        // `output_tokens_details.thinking_tokens` only appears in responses
+        // from newer Anthropic SDK and API versions, so older pinned cassettes
+        // will not carry it.
+        const metrics = (span?.metrics ?? {}) as Record<string, unknown>;
+        if ("completion_thinking_tokens" in metrics) {
+          expect(metrics.completion_thinking_tokens).toEqual(
+            expect.any(Number),
+          );
+          expect(
+            metrics.completion_thinking_tokens as number,
+          ).toBeLessThanOrEqual(metrics.completion_tokens as number);
+        }
         expect(
           output?.content?.some((block) => block.type === "thinking"),
         ).toBe(true);
diff --git a/js/src/instrumentation/plugins/anthropic-plugin.test.ts b/js/src/instrumentation/plugins/anthropic-plugin.test.ts
index ffad58aff..689cc6aa9 100644
--- a/js/src/instrumentation/plugins/anthropic-plugin.test.ts
+++ b/js/src/instrumentation/plugins/anthropic-plugin.test.ts
@@ -159,6 +159,44 @@ describe("parseMetricsFromUsage", () => {
     });
   });
 
+  it("should map output_tokens_details.thinking_tokens to completion_thinking_tokens", () => {
+    const usage = {
+      input_tokens: 100,
+      output_tokens: 80,
+      output_tokens_details: {
+        thinking_tokens: 20,
+      },
+    };
+
+    const result = parseMetricsFromUsageForTest(usage);
+
+    // Thinking tokens are a subset of `output_tokens`, so `completion_tokens`
+    // stays the inclusive total.
+    expect(result).toEqual({
+      prompt_tokens: 100,
+      completion_tokens: 80,
+      completion_thinking_tokens: 20,
+    });
+  });
+
+  it("should ignore a null or non-number output token breakdown", () => {
+    expect(
+      parseMetricsFromUsageForTest({
+        input_tokens: 100,
+        output_tokens: 80,
+        output_tokens_details: null,
+      }),
+    ).toEqual({ prompt_tokens: 100, completion_tokens: 80 });
+
+    expect(
+      parseMetricsFromUsageForTest({
+        input_tokens: 100,
+        output_tokens: 80,
+        output_tokens_details: { thinking_tokens: "not a number" },
+      }),
+    ).toEqual({ prompt_tokens: 100, completion_tokens: 80 });
+  });
+
   it("should ignore non-number token values", () => {
     const usage = {
       input_tokens: "not a number",
@@ -283,6 +321,40 @@ describe("aggregateAnthropicStreamChunks", () => {
     });
   });
 
+  it("should carry thinking tokens through from the final message_delta usage", () => {
+    const chunks = [
+      {
+        type: "message_start",
+        message: {
+          usage: {
+            input_tokens: 10,
+            output_tokens: 0,
+          },
+        },
+      },
+      {
+        type: "content_block_delta",
+        delta: { type: "thinking_delta", thinking: "hmm" },
+      },
+      {
+        type: "message_delta",
+        usage: {
+          output_tokens: 80,
+          output_tokens_details: { thinking_tokens: 20 },
+        },
+      },
+    ];
+
+    const result = aggregateAnthropicStreamChunksForTest(chunks);
+
+    expect(result.metrics).toMatchObject({
+      prompt_tokens: 10,
+      completion_tokens: 80,
+      completion_thinking_tokens: 20,
+      tokens: 90, // thinking tokens are already inside completion_tokens
+    });
+  });
+
   it("should concatenate multiple text deltas", () => {
     const chunks = [
       {
diff --git a/js/src/instrumentation/plugins/anthropic-plugin.ts b/js/src/instrumentation/plugins/anthropic-plugin.ts
index 36cad5a5c..4b22d6868 100644
--- a/js/src/instrumentation/plugins/anthropic-plugin.ts
+++ b/js/src/instrumentation/plugins/anthropic-plugin.ts
@@ -843,6 +843,18 @@ export function parseMetricsFromUsage(
     }
   }
 
+  // Extended and adaptive thinking report the reasoning share of the billed
+  // output tokens. This mirrors the OpenAI plugin, where
+  // `output_tokens_details.reasoning_tokens` becomes
+  // `completion_reasoning_tokens`. The value is a subset of `output_tokens`,
+  // not additional tokens, so it is not rolled into the total.
+  if (isObject(usage.output_tokens_details)) {
+    const thinkingTokens = usage.output_tokens_details.thinking_tokens;
+    if (typeof thinkingTokens === "number") {
+      metrics.completion_thinking_tokens = thinkingTokens;
+    }
+  }
+
   if (isObject(usage.server_tool_use)) {
     for (const [name, value] of Object.entries(usage.server_tool_use)) {
       if (typeof value === "number") {
diff --git a/js/src/vendor-sdk-types/anthropic.ts b/js/src/vendor-sdk-types/anthropic.ts
index 89cdc644f..df81fa68e 100644
--- a/js/src/vendor-sdk-types/anthropic.ts
+++ b/js/src/vendor-sdk-types/anthropic.ts
@@ -195,10 +195,21 @@ export interface AnthropicUsage {
   cache_read_input_tokens?: number;
   cache_creation_input_tokens?: number;
   cache_creation?: AnthropicCacheCreationUsage | null;
+  output_tokens_details?: AnthropicOutputTokensDetails | null;
   server_tool_use?: AnthropicServerToolUseUsage;
   [key: string]: unknown;
 }
 
+/**
+ * Breakdown of output tokens by category. Reported when extended or adaptive
+ * thinking is active; `output_tokens` stays the authoritative billing total and
+ * these are a subset of it.
+ */
+export interface AnthropicOutputTokensDetails {
+  thinking_tokens?: number;
+  [key: string]: unknown;
+}
+
 /**
  * Per-TTL breakdown of cache-write tokens. Only recent Anthropic SDK versions
  * report this; older ones expose just `cache_creation_input_tokens`.

From fb0c825b5b1bf0036d3d1fe2f78376cf14a1801d Mon Sep 17 00:00:00 2001
From: lforst <8118419+lforst@users.noreply.github.com>
Date: Wed, 19 Aug 2026 16:18:48 +0000
Subject: [PATCH 2/4] use correct metric

---
 .changeset/anthropic-thinking-tokens-metric.md    |  5 -----
 .../anthropic-v0-latest-wrapped.span-tree.json    |  2 +-
 .../anthropic-v0-latest-wrapped.span-tree.txt     |  2 +-
 .../anthropic-v0-latest.span-tree.json            |  2 +-
 .../anthropic-v0-latest.span-tree.txt             |  2 +-
 .../anthropic-instrumentation/assertions.ts       | 15 ++++-----------
 .../plugins/anthropic-plugin.test.ts              |  6 +++---
 .../instrumentation/plugins/anthropic-plugin.ts   |  2 +-
 8 files changed, 12 insertions(+), 24 deletions(-)
 delete mode 100644 .changeset/anthropic-thinking-tokens-metric.md

diff --git a/.changeset/anthropic-thinking-tokens-metric.md b/.changeset/anthropic-thinking-tokens-metric.md
deleted file mode 100644
index 74949c1c0..000000000
--- a/.changeset/anthropic-thinking-tokens-metric.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"braintrust": patch
----
-
-fix(anthropic): Record `output_tokens_details.thinking_tokens` as `completion_thinking_tokens`
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json
index fdcd2d7b8..734032321 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.json
@@ -646,7 +646,7 @@
                 }
               },
               "metrics": {
-                "completion_thinking_tokens": 42,
+                "completion_reasoning_tokens": 42,
                 "completion_tokens": 48,
                 "prompt_cache_creation_1h_tokens": 0,
                 "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt
index 927553ccd..461f88e29 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest-wrapped.span-tree.txt
@@ -573,7 +573,7 @@ span_tree:
     │         }
     │       }
     │       metrics: {
-    │         "completion_thinking_tokens": 42,
+    │         "completion_reasoning_tokens": 42,
     │         "completion_tokens": 48,
     │         "prompt_cache_creation_1h_tokens": 0,
     │         "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json
index fdcd2d7b8..734032321 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.json
@@ -646,7 +646,7 @@
                 }
               },
               "metrics": {
-                "completion_thinking_tokens": 42,
+                "completion_reasoning_tokens": 42,
                 "completion_tokens": 48,
                 "prompt_cache_creation_1h_tokens": 0,
                 "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt
index 927553ccd..461f88e29 100644
--- a/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt
+++ b/e2e/scenarios/anthropic-instrumentation/__snapshots__/anthropic-v0-latest.span-tree.txt
@@ -573,7 +573,7 @@ span_tree:
     │         }
     │       }
     │       metrics: {
-    │         "completion_thinking_tokens": 42,
+    │         "completion_reasoning_tokens": 42,
     │         "completion_tokens": 48,
     │         "prompt_cache_creation_1h_tokens": 0,
     │         "prompt_cache_creation_5m_tokens": 0,
diff --git a/e2e/scenarios/anthropic-instrumentation/assertions.ts b/e2e/scenarios/anthropic-instrumentation/assertions.ts
index ea7bdaa21..0e783ae2c 100644
--- a/e2e/scenarios/anthropic-instrumentation/assertions.ts
+++ b/e2e/scenarios/anthropic-instrumentation/assertions.ts
@@ -746,19 +746,12 @@ export function defineAnthropicInstrumentationAssertions(options: {
           time_to_first_token: expect.any(Number),
           prompt_tokens: expect.any(Number),
           completion_tokens: expect.any(Number),
+          completion_reasoning_tokens: expect.any(Number),
         });
-        // `output_tokens_details.thinking_tokens` only appears in responses
-        // from newer Anthropic SDK and API versions, so older pinned cassettes
-        // will not carry it.
         const metrics = (span?.metrics ?? {}) as Record<string, unknown>;
-        if ("completion_thinking_tokens" in metrics) {
-          expect(metrics.completion_thinking_tokens).toEqual(
-            expect.any(Number),
-          );
-          expect(
-            metrics.completion_thinking_tokens as number,
-          ).toBeLessThanOrEqual(metrics.completion_tokens as number);
-        }
+        expect(
+          metrics.completion_reasoning_tokens as number,
+        ).toBeLessThanOrEqual(metrics.completion_tokens as number);
         expect(
           output?.content?.some((block) => block.type === "thinking"),
         ).toBe(true);
diff --git a/js/src/instrumentation/plugins/anthropic-plugin.test.ts b/js/src/instrumentation/plugins/anthropic-plugin.test.ts
index 689cc6aa9..c69f6023f 100644
--- a/js/src/instrumentation/plugins/anthropic-plugin.test.ts
+++ b/js/src/instrumentation/plugins/anthropic-plugin.test.ts
@@ -159,7 +159,7 @@ describe("parseMetricsFromUsage", () => {
     });
   });
 
-  it("should map output_tokens_details.thinking_tokens to completion_thinking_tokens", () => {
+  it("should map output_tokens_details.thinking_tokens to completion_reasoning_tokens", () => {
     const usage = {
       input_tokens: 100,
       output_tokens: 80,
@@ -175,7 +175,7 @@ describe("parseMetricsFromUsage", () => {
     expect(result).toEqual({
       prompt_tokens: 100,
       completion_tokens: 80,
-      completion_thinking_tokens: 20,
+      completion_reasoning_tokens: 20,
     });
   });
 
@@ -350,7 +350,7 @@ describe("aggregateAnthropicStreamChunks", () => {
     expect(result.metrics).toMatchObject({
       prompt_tokens: 10,
       completion_tokens: 80,
-      completion_thinking_tokens: 20,
+      completion_reasoning_tokens: 20,
       tokens: 90, // thinking tokens are already inside completion_tokens
     });
   });
diff --git a/js/src/instrumentation/plugins/anthropic-plugin.ts b/js/src/instrumentation/plugins/anthropic-plugin.ts
index 4b22d6868..68b981ceb 100644
--- a/js/src/instrumentation/plugins/anthropic-plugin.ts
+++ b/js/src/instrumentation/plugins/anthropic-plugin.ts
@@ -851,7 +851,7 @@ export function parseMetricsFromUsage(
   if (isObject(usage.output_tokens_details)) {
     const thinkingTokens = usage.output_tokens_details.thinking_tokens;
     if (typeof thinkingTokens === "number") {
-      metrics.completion_thinking_tokens = thinkingTokens;
+      metrics.completion_reasoning_tokens = thinkingTokens;
     }
   }
 

From 1fcd585dbbc4eff584a96eb7f8223853d38a0b8f Mon Sep 17 00:00:00 2001
From: lforst <8118419+lforst@users.noreply.github.com>
Date: Wed, 19 Aug 2026 16:32:20 +0000
Subject: [PATCH 3/4] Update PR #2382

---
 .changeset/anthropic-thinking-tokens-metric.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/anthropic-thinking-tokens-metric.md

diff --git a/.changeset/anthropic-thinking-tokens-metric.md b/.changeset/anthropic-thinking-tokens-metric.md
new file mode 100644
index 000000000..b16538632
--- /dev/null
+++ b/.changeset/anthropic-thinking-tokens-metric.md
@@ -0,0 +1,5 @@
+---
+"braintrust": patch
+---
+
+fix(anthropic): Record thinking tokens as metric

From bec23ad9f0f5d441ba9d9905e0ebeb9ab42b7829 Mon Sep 17 00:00:00 2001
From: lforst <8118419+lforst@users.noreply.github.com>
Date: Wed, 19 Aug 2026 17:09:07 +0000
Subject: [PATCH 4/4] Update PR #2382

---
 .../anthropic-instrumentation/assertions.ts       |  8 ++++----
 .../plugins/anthropic-plugin.test.ts              |  6 ++----
 .../instrumentation/plugins/anthropic-plugin.ts   |  6 +-----
 js/src/vendor-sdk-types/anthropic.ts              | 15 ++++-----------
 4 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/e2e/scenarios/anthropic-instrumentation/assertions.ts b/e2e/scenarios/anthropic-instrumentation/assertions.ts
index 0e783ae2c..812053b00 100644
--- a/e2e/scenarios/anthropic-instrumentation/assertions.ts
+++ b/e2e/scenarios/anthropic-instrumentation/assertions.ts
@@ -748,10 +748,10 @@ export function defineAnthropicInstrumentationAssertions(options: {
           completion_tokens: expect.any(Number),
           completion_reasoning_tokens: expect.any(Number),
         });
-        const metrics = (span?.metrics ?? {}) as Record<string, unknown>;
-        expect(
-          metrics.completion_reasoning_tokens as number,
-        ).toBeLessThanOrEqual(metrics.completion_tokens as number);
+        const metrics = span?.metrics as Record<string, number>;
+        expect(metrics.completion_reasoning_tokens).toBeLessThanOrEqual(
+          metrics.completion_tokens,
+        );
         expect(
           output?.content?.some((block) => block.type === "thinking"),
         ).toBe(true);
diff --git a/js/src/instrumentation/plugins/anthropic-plugin.test.ts b/js/src/instrumentation/plugins/anthropic-plugin.test.ts
index c69f6023f..a711c3b7a 100644
--- a/js/src/instrumentation/plugins/anthropic-plugin.test.ts
+++ b/js/src/instrumentation/plugins/anthropic-plugin.test.ts
@@ -170,8 +170,6 @@ describe("parseMetricsFromUsage", () => {
 
     const result = parseMetricsFromUsageForTest(usage);
 
-    // Thinking tokens are a subset of `output_tokens`, so `completion_tokens`
-    // stays the inclusive total.
     expect(result).toEqual({
       prompt_tokens: 100,
       completion_tokens: 80,
@@ -321,7 +319,7 @@ describe("aggregateAnthropicStreamChunks", () => {
     });
   });
 
-  it("should carry thinking tokens through from the final message_delta usage", () => {
+  it("should carry thinking tokens through from message_delta without double counting", () => {
     const chunks = [
       {
         type: "message_start",
@@ -351,7 +349,7 @@ describe("aggregateAnthropicStreamChunks", () => {
       prompt_tokens: 10,
       completion_tokens: 80,
       completion_reasoning_tokens: 20,
-      tokens: 90, // thinking tokens are already inside completion_tokens
+      tokens: 90,
     });
   });
 
diff --git a/js/src/instrumentation/plugins/anthropic-plugin.ts b/js/src/instrumentation/plugins/anthropic-plugin.ts
index 68b981ceb..e184c927d 100644
--- a/js/src/instrumentation/plugins/anthropic-plugin.ts
+++ b/js/src/instrumentation/plugins/anthropic-plugin.ts
@@ -843,11 +843,7 @@ export function parseMetricsFromUsage(
     }
   }
 
-  // Extended and adaptive thinking report the reasoning share of the billed
-  // output tokens. This mirrors the OpenAI plugin, where
-  // `output_tokens_details.reasoning_tokens` becomes
-  // `completion_reasoning_tokens`. The value is a subset of `output_tokens`,
-  // not additional tokens, so it is not rolled into the total.
+  // Thinking tokens are already included in output_tokens.
   if (isObject(usage.output_tokens_details)) {
     const thinkingTokens = usage.output_tokens_details.thinking_tokens;
     if (typeof thinkingTokens === "number") {
diff --git a/js/src/vendor-sdk-types/anthropic.ts b/js/src/vendor-sdk-types/anthropic.ts
index df81fa68e..cbe9225c3 100644
--- a/js/src/vendor-sdk-types/anthropic.ts
+++ b/js/src/vendor-sdk-types/anthropic.ts
@@ -195,21 +195,14 @@ export interface AnthropicUsage {
   cache_read_input_tokens?: number;
   cache_creation_input_tokens?: number;
   cache_creation?: AnthropicCacheCreationUsage | null;
-  output_tokens_details?: AnthropicOutputTokensDetails | null;
+  output_tokens_details?: {
+    thinking_tokens?: number;
+    [key: string]: unknown;
+  } | null;
   server_tool_use?: AnthropicServerToolUseUsage;
   [key: string]: unknown;
 }
 
-/**
- * Breakdown of output tokens by category. Reported when extended or adaptive
- * thinking is active; `output_tokens` stays the authoritative billing total and
- * these are a subset of it.
- */
-export interface AnthropicOutputTokensDetails {
-  thinking_tokens?: number;
-  [key: string]: unknown;
-}
-
 /**
  * Per-TTL breakdown of cache-write tokens. Only recent Anthropic SDK versions
  * report this; older ones expose just `cache_creation_input_tokens`.