@@ -230,6 +230,8 @@ export {
 export { wrapToolsWithSpans, extractLLMFromParams, extractAgentNameFromParams } from './tracing/langgraph/utils';
 export { LANGGRAPH_INTEGRATION_NAME } from './tracing/langgraph/constants';
 export type { LangGraphOptions, LangGraphIntegration, CompiledGraph } from './tracing/langgraph/types';
+export { instrumentWorkersAiClient } from './tracing/workers-ai';
+export type { WorkersAiClient, WorkersAiOptions } from './tracing/workers-ai/types';
 // eslint-disable-next-line typescript/no-deprecated
 export type { OpenAiClient, OpenAiOptions, InstrumentedMethod } from './tracing/openai/types';
 export type {
 
@@ -0,0 +1,10 @@
+/**
+ * The provider value for the `gen_ai.provider.name` attribute.
+ * @see https://developers.cloudflare.com/workers-ai/
+ */
+export const WORKERS_AI_PROVIDER_NAME = 'cloudflare.workers_ai';
+
+/**
+ * The Sentry origin for spans created by the Workers AI instrumentation.
+ */
+export const WORKERS_AI_ORIGIN = 'auto.ai.cloudflare.workers_ai';
@@ -0,0 +1,133 @@
+import { SPAN_STATUS_ERROR } from '../../tracing';
+import { startSpan, startSpanManual } from '../../tracing/trace';
+import type { Span } from '../../types/span';
+import { isObjectLike } from '../../utils/is';
+import { resolveAIRecordingOptions, shouldEnableTruncation } from '../ai/utils';
+import { instrumentWorkersAiStream } from './streaming';
+import type { WorkersAiOptions } from './types';
+import { addRequestAttributes, addResponseAttributes, extractRequestAttributes, getOperationName } from './utils';
+
+// Adapted from /server-utils/src/vercel-ai/util.ts
+// TODO(v11): Reuse this function once this gets moved to @sentry/server-utils
+// Workers AI streaming responses are SSE byte streams, so we narrow to `Uint8Array`.
+function isReadableStream(value: unknown): value is ReadableStream<Uint8Array> {
+  return (
+    isObjectLike(value) &&
+    typeof (value as { pipeThrough?: unknown }).pipeThrough === 'function' &&
+    typeof (value as { getReader?: unknown }).getReader === 'function'
+  );
+}
+
+/**
+ * Wrap the `run` method of the Workers AI binding with Sentry tracing.
+ */
+function instrumentRun(
+  originalRun: (...args: unknown[]) => Promise<unknown>,
+  context: unknown,
+  options: WorkersAiOptions & Required<Pick<WorkersAiOptions, 'recordInputs' | 'recordOutputs'>>,
+): (...args: unknown[]) => Promise<unknown> {
+  return function instrumentedRun(...args: unknown[]): Promise<unknown> {
+    const [model, inputs, runOptions] = args as [unknown, unknown, Record<string, unknown> | undefined];
+
+    const operationName = getOperationName(inputs);
+    const requestAttributes = extractRequestAttributes(model, inputs, operationName);
+    const modelName = typeof model === 'string' ? model : 'unknown';
+
+    const isStreamRequested =
+      !!inputs && typeof inputs === 'object' && (inputs as { stream?: unknown }).stream === true;
+    const returnsRawResponse =
+      !!runOptions &&
+      typeof runOptions === 'object' &&
+      (runOptions.returnRawResponse === true || runOptions.websocket === true);
+
+    const spanConfig = {
+      name: `${operationName} ${modelName}`,
+      op: `gen_ai.${operationName}`,
+      attributes: requestAttributes,
+    };
+
+    if (isStreamRequested && !returnsRawResponse) {
+      return startSpanManual(spanConfig, (span: Span) => {
+        // `startSpanManual` does not auto-end the span, so we must end it on every exit path,
+        // including a synchronous throw from `run`.
+        const handleError = (error: unknown): never => {
+          span.setStatus({ code: SPAN_STATUS_ERROR, message: 'internal_error' });
+          span.end();
+          throw error;
+        };
+
+        let originalResult: Promise<unknown>;
+
+        try {
+          originalResult = originalRun.apply(context, args) as Promise<unknown>;
+        } catch (error) {
+          return handleError(error);
+        }
+
+        if (options.recordInputs) {
+          addRequestAttributes(span, inputs, operationName, shouldEnableTruncation(options.enableTruncation));
+        }
+
+        return originalResult.then(result => {
+          if (isReadableStream(result)) {
+            return instrumentWorkersAiStream(result, span, options.recordOutputs);
+          }
+
+          // The model did not actually return a stream — finalize the span eagerly.
+          addResponseAttributes(span, result, options.recordOutputs);
+          span.end();
+          return result;
+        }, handleError);
+      });
+    }
+
+    return startSpan(spanConfig, (span: Span) => {
+      const originalResult = originalRun.apply(context, args) as Promise<unknown>;
+
+      if (options.recordInputs) {
+        addRequestAttributes(span, inputs, operationName, shouldEnableTruncation(options.enableTruncation));
+      }
+
+      return originalResult.then(result => {
+        if (!returnsRawResponse) {
+          addResponseAttributes(span, result, options.recordOutputs);
+        }
+        return result;
+      });
+    });
+  };
+}
+
+/**
+ * Instrument a Cloudflare Workers AI binding (`env.AI`) with Sentry tracing.
+ *
+ * This wraps the binding's `run` method to create `gen_ai` spans following the
+ * Sentry AI Agents conventions. All other methods are passed through untouched.
+ *
+ * In `@sentry/cloudflare`, the `env.AI` binding is instrumented automatically —
+ * wrapping manually is only needed to pass custom options.
+ *
+ * @example
+ * ```javascript
+ * const ai = Sentry.instrumentWorkersAiClient(env.AI, { recordInputs: true, recordOutputs: true });
+ * const result = await ai.run('@cf/meta/llama-3.1-8b-instruct', { prompt: 'Hello' });
+ * ```
+ */
+export function instrumentWorkersAiClient<T extends object>(client: T, options?: WorkersAiOptions): T {
+  const resolvedOptions = resolveAIRecordingOptions(options);
+
+  const instrumented = new Proxy(client, {
+    get(target: object, prop: string | symbol, receiver: unknown): unknown {
+      const value = Reflect.get(target, prop, receiver);
+
+      if (prop === 'run' && typeof value === 'function') {
+        return instrumentRun(value as (...args: unknown[]) => Promise<unknown>, target, resolvedOptions);
+      }
+
+      // Bind passed-through functions to the original target to preserve `this` (e.g. private fields).
+      return typeof value === 'function' ? (value as (...args: unknown[]) => unknown).bind(target) : value;
+    },
+  }) as T;
+
+  return instrumented;
+}
@@ -0,0 +1,229 @@
+import { SPAN_STATUS_ERROR } from '../../tracing';
+import type { Span } from '../../types/span';
+import { endStreamSpan, type StreamResponseState } from '../ai/utils';
+import type { WorkersAiUsage } from './types';
+import { setOutputMessagesAttribute } from './utils';
+
+interface WorkersAiStreamingToolCall {
+  index?: number;
+  id?: string;
+  type?: string;
+  function?: { name?: string; arguments?: string };
+  // Some Workers AI models stream tool calls with the name/arguments at the top
+  // level of the tool-call object instead of nested under `function`.
+  name?: string;
+  arguments?: string;
+}
+
+interface WorkersAiStreamChunk {
+  // Native Workers AI streaming shape (`env.AI.run` with `stream: true`).
+  response?: unknown;
+  tool_calls?: unknown[];
+  // OpenAI-compatible streaming shape emitted for models routed through the
+  // OpenAI-compatible endpoint (e.g. via `workers-ai-provider`).
+  choices?: Array<{
+    delta?: { content?: unknown; tool_calls?: WorkersAiStreamingToolCall[] };
+    finish_reason?: unknown;
+  }>;
+  usage?: WorkersAiUsage & { prompt_tokens?: number; completion_tokens?: number; total_tokens?: number };
+}
+
+/**
+ * Accumulate a fragmented OpenAI-compatible tool call (delivered across multiple
+ * `choices[].delta.tool_calls` chunks) into the index-keyed accumulator.
+ */
+function accumulateStreamingToolCalls(
+  toolCalls: WorkersAiStreamingToolCall[],
+  accumulator: Record<number, WorkersAiStreamingToolCall>,
+): void {
+  for (const toolCall of toolCalls) {
+    // Normalize both shapes: name/arguments nested under `function`, or at the top level.
+    const name = toolCall.function?.name ?? toolCall.name;
+    const args = toolCall.function?.arguments ?? toolCall.arguments;
+
+    // A tool call must carry at least a name or argument fragment to be meaningful.
+    if (name == null && args == null) {
+      continue;
+    }
+
+    const index = toolCall.index ?? 0;
+    const existing = accumulator[index];
+
+    if (!existing) {
+      accumulator[index] = {
+        index,
+        id: toolCall.id,
+        type: toolCall.type,
+        function: {
+          name,
+          arguments: args ?? '',
+        },
+      };
+    } else if (existing.function) {
+      if (name && !existing.function.name) {
+        existing.function.name = name;
+      }
+      if (args) {
+        existing.function.arguments = `${existing.function.arguments ?? ''}${args}`;
+      }
+    }
+  }
+}
+
+/**
+ * Parse a single SSE line (`data: {...}`) and accumulate its data into the streaming state.
+ *
+ * Handles both the native Workers AI shape (top-level `response`/`tool_calls`) and the
+ * OpenAI-compatible shape (`choices[].delta.content`/`choices[].delta.tool_calls`), because
+ * the same `run()` call transparently yields either format depending on the model.
+ */
+function processLine(
+  line: string,
+  state: StreamResponseState,
+  recordOutputs: boolean,
+  toolCallAccumulator: Record<number, WorkersAiStreamingToolCall>,
+): void {
+  const trimmed = line.trim();
+  if (!trimmed.startsWith('data:')) {
+    return;
+  }
+
+  const data = trimmed.slice('data:'.length).trim();
+  if (!data || data === '[DONE]') {
+    return;
+  }
+
+  let parsed: WorkersAiStreamChunk;
+  try {
+    parsed = JSON.parse(data) as WorkersAiStreamChunk;
+  } catch {
+    return;
+  }
+
+  if (parsed.usage) {
+    if (typeof parsed.usage.prompt_tokens === 'number') {
+      state.promptTokens = parsed.usage.prompt_tokens;
+    }
+    if (typeof parsed.usage.completion_tokens === 'number') {
+      state.completionTokens = parsed.usage.completion_tokens;
+    }
+    if (typeof parsed.usage.total_tokens === 'number') {
+      state.totalTokens = parsed.usage.total_tokens;
+    }
+  }
+
+  if (recordOutputs && typeof parsed.response === 'string') {
+    state.responseTexts.push(parsed.response);
+  }
+
+  if (recordOutputs && Array.isArray(parsed.tool_calls) && parsed.tool_calls.length > 0) {
+    state.toolCalls.push(...parsed.tool_calls);
+  }
+
+  if (Array.isArray(parsed.choices)) {
+    for (const choice of parsed.choices) {
+      if (recordOutputs && typeof choice.delta?.content === 'string' && choice.delta.content) {
+        state.responseTexts.push(choice.delta.content);
+      }
+      if (recordOutputs && Array.isArray(choice.delta?.tool_calls)) {
+        accumulateStreamingToolCalls(choice.delta.tool_calls, toolCallAccumulator);
+      }
+      if (typeof choice.finish_reason === 'string') {
+        state.finishReasons.push(choice.finish_reason);
+      }
+    }
+  }
+}
+
+/**
+ * Wrap a Workers AI streaming response (a server-sent-events `ReadableStream`) so we can
+ * accumulate the response text and token usage while passing the original bytes through untouched.
+ *
+ * The span is ended once the consumer finishes reading (or cancels) the stream.
+ */
+export function instrumentWorkersAiStream(
+  stream: ReadableStream<Uint8Array>,
+  span: Span,
+  recordOutputs: boolean,
+): ReadableStream<Uint8Array> {
+  const reader = stream.getReader();
+  const decoder = new TextDecoder();
+
+  const state: StreamResponseState = {
+    responseId: '',
+    responseModel: '',
+    finishReasons: [],
+    responseTexts: [],
+    toolCalls: [],
+    promptTokens: undefined,
+    completionTokens: undefined,
+    totalTokens: undefined,
+  };
+
+  // OpenAI-compatible tool calls arrive fragmented across chunks and are keyed by index;
+  // accumulate them here and flatten into `state.toolCalls` once the stream ends.
+  const toolCallAccumulator: Record<number, WorkersAiStreamingToolCall> = {};
+
+  let buffer = '';
+  let spanEnded = false;
+
+  const finish = (): void => {
+    if (spanEnded) {
+      return;
+    }
+    spanEnded = true;
+
+    if (recordOutputs) {
+      const accumulatedToolCalls = Object.values(toolCallAccumulator);
+      if (accumulatedToolCalls.length > 0) {
+        state.toolCalls.push(...accumulatedToolCalls);
+      }
+
+      // Set the authoritative `gen_ai.output.messages` alongside the deprecated response
+      // attributes `endStreamSpan` writes, so tool calls survive Relay's lossy migration.
+      setOutputMessagesAttribute(span, {
+        responseText: state.responseTexts.join(''),
+        toolCalls: state.toolCalls,
+      });
+    }
+
+    endStreamSpan(span, state, recordOutputs);
+  };
+
+  const flushBuffer = (isDone: boolean): void => {
+    const lines = buffer.split('\n');
+    // Keep the last (potentially incomplete) line in the buffer unless the stream is done.
+    buffer = isDone ? '' : (lines.pop() ?? '');
+    for (const line of lines) {
+      processLine(line, state, recordOutputs, toolCallAccumulator);
+    }
+  };
+
+  return new ReadableStream<Uint8Array>({
+    async pull(controller) {
+      try {
+        const { done, value } = await reader.read();
+
+        if (done) {
+          buffer += decoder.decode();
+          flushBuffer(true);
+          finish();
+          controller.close();
+          return;
+        }
+
+        buffer += decoder.decode(value, { stream: true });
+        flushBuffer(false);
+        controller.enqueue(value);
+      } catch (error) {
+        span.setStatus({ code: SPAN_STATUS_ERROR, message: 'internal_error' });
+        finish();
+        controller.error(error);
+      }
+    },
+    async cancel(reason) {
+      finish();
+      await reader.cancel(reason);
+    },
+  });
+}