diff --git a/gateway/package.json b/gateway/package.json
index 81bac5a..43291c6 100644
--- a/gateway/package.json
+++ b/gateway/package.json
@@ -5,7 +5,7 @@
   "main": "src/index.ts",
   "scripts": {
     "typecheck": "tsgo --noEmit && cd test && tsgo --noEmit",
-    "test": "vitest"
+    "test": "vitest --reporter=verbose"
   },
   "dependencies": {
     "@opentelemetry/api": "^1.9.0",
diff --git a/gateway/src/gateway.ts b/gateway/src/gateway.ts
index df85ea7..7d25dc9 100644
--- a/gateway/src/gateway.ts
+++ b/gateway/src/gateway.ts
@@ -64,32 +64,31 @@ export async function gateway(
   const result = await proxy.dispatch()
 
   // This doesn't work on streaming because the `result` object is returned as soon as we create the streaming response.
-  if (!('responseStream' in result) && !('httpStatusCode' in result)) {
+  if (!('responseStream' in result) && !('response' in result)) {
     const [spanName, attributes, level] = genAiOtelAttributes(result, proxy)
     dispatchSpan.end(spanName, attributes, { level })
   }
 
   let response: Response
-  if ('httpStatusCode' in result) {
-    const { httpStatusCode, responseHeaders, responseBody } = result
-    response = new Response(responseBody, { status: httpStatusCode, headers: responseHeaders })
+  if ('response' in result) {
+    response = result.response
   } else if ('responseStream' in result) {
-    const { successStatus: status, responseHeaders: headers, responseStream, disableKey, waitCompletion } = result
+    const { successStatus: status, responseHeaders: headers, responseStream, disableKey, onStreamComplete } = result
     runAfter(
       ctx,
       'recordSpend',
       (async () => {
-        await waitCompletion
-        const cost = proxy.cost
-        if (cost) {
-          await recordSpend(apiKeyInfo, cost, options)
-        } else {
+        const complete = await onStreamComplete
+        if ('cost' in complete && complete.cost) {
+          await recordSpend(apiKeyInfo, complete.cost, options)
+        } else if ('error' in complete) {
           const { key: _key, ...context } = apiKeyInfo
           if (disableKey) {
-            logfire.error('api key blocked', { context, error: 'Unable to calculate cost' })
-            await blockApiKey(apiKeyInfo, options, 'Unable to calculate cost')
+            logfire.reportError('api key blocked', complete.error, { context })
+            await blockApiKey(apiKeyInfo, options, JSON.stringify(complete.error))
+          } else {
+            logfire.reportError('Unable to calculate cost', complete.error, { context })
           }
-          logfire.error('Unable to calculate cost', { context, error: 'Unable to calculate cost' })
         }
         await otel.send()
       })(),
diff --git a/gateway/src/otel/attributes.ts b/gateway/src/otel/attributes.ts
index 401a9fb..129b1bb 100644
--- a/gateway/src/otel/attributes.ts
+++ b/gateway/src/otel/attributes.ts
@@ -58,6 +58,25 @@ export function genAiOtelAttributes(
   return [spanName, attributes, level]
 }
 
+export function attributesFromRequest(request: Request): Attributes {
+  return {
+    'http.request.method': request.method,
+    'url.full': request.url,
+    ...Object.fromEntries(
+      Array.from(request.headers.entries()).map(([name, value]) => [`http.request.header.${name}`, value]),
+    ),
+  }
+}
+
+export function attributesFromResponse(response: Response): Attributes {
+  return {
+    'http.response.status_code': response.status,
+    ...Object.fromEntries(
+      Array.from(response.headers.entries()).map(([name, value]) => [`http.response.header.${name}`, value]),
+    ),
+  }
+}
+
 /** Semantic conventions for Generative AI
  * @see https://opentelemetry.io/docs/specs/semconv/registry/attributes/gen-ai/
  */
diff --git a/gateway/src/providers/default.ts b/gateway/src/providers/default.ts
index 2032648..4a0cacc 100644
--- a/gateway/src/providers/default.ts
+++ b/gateway/src/providers/default.ts
@@ -12,7 +12,7 @@ import type { GatewayOptions } from '..'
 import type { ModelAPI } from '../api'
 import type { BaseAPI } from '../api/base'
 import type { OtelSpan } from '../otel'
-import type { GenAIAttributes } from '../otel/attributes'
+import { attributesFromRequest, attributesFromResponse, type GenAIAttributes } from '../otel/attributes'
 import type { ApiKeyInfo, ProviderProxy } from '../types'
 import { runAfter } from '../utils'
 
@@ -29,10 +29,7 @@ export interface ProxySuccess {
 }
 
 export interface ProxyWhitelistedEndpoint {
-  requestBody: string
-  httpStatusCode: number
-  responseHeaders: Headers
-  responseBody: string
+  response: Response
 }
 
 export interface ProxyStreamingSuccess {
@@ -42,7 +39,7 @@ export interface ProxyStreamingSuccess {
   responseHeaders: Headers
   responseStream: ReadableStream
   otelAttributes?: GenAIAttributes
-  waitCompletion: Promise<void>
+  onStreamComplete: Promise<{ cost?: number } | { error: Error }>
   // In case we get to the end of the response, and we are unable to calculate the cost, we need to know if we can disable the key.
   disableKey?: boolean
 }
@@ -297,27 +294,16 @@ export class DefaultProviderProxy {
     const response = await this.fetch(url, { method, headers: requestHeaders, body: requestBodyText })
 
     if (this.isWhitelistedEndpoint()) {
-      // TODO(Marcelo): We can't read the body if it's a streaming response.
-      const responseBody = await response.text()
-      const { headers, status } = response
       this.otelSpan.end(
         `${this.request.method} ${this.restOfPath}`,
         {
-          'http.method': this.request.method,
-          'http.url': this.restOfPath,
-          'http.response.status_code': status,
+          ...attributesFromRequest(this.request),
+          ...attributesFromResponse(response),
           'http.request.body.text': requestBodyText,
-          'http.response.body.text': responseBody,
-          ...Object.fromEntries(
-            Array.from(requestHeaders.entries()).map(([name, value]) => [`http.request.header.${name}`, value]),
-          ),
-          ...Object.fromEntries(
-            Array.from(headers.entries()).map(([name, value]) => [`http.response.header.${name}`, value]),
-          ),
         },
         { level: 'info' },
       )
-      return { requestBody: requestBodyText, httpStatusCode: status, responseHeaders: headers, responseBody }
+      return { response }
     }
 
     // Each provider should be able to modify the response headers, e.g. remove openai org
@@ -402,7 +388,23 @@ export class DefaultProviderProxy {
 
     // Track completion but don't wait for it before returning
     this.runAfter('extract-stream', extractionPromise)
-    const waitCompletion = extractionPromise.catch(() => {}) // Swallow errors, already logged
+
+    const onStreamComplete = extractionPromise
+      .then((result) => {
+        // TODO(Marcelo): I think we actually need to emit 2 spans: one for HTTP, and another for the LLM.
+        this.otelSpan.end(
+          `chat ${modelAPI.extractedRequest?.requestModel ?? 'streaming'}`,
+          {
+            ...modelAPI.toGenAiOtelAttributes(),
+            ...attributesFromRequest(this.request),
+            ...attributesFromResponse(response),
+          },
+          { level: 'info' },
+        )
+
+        return result
+      })
+      .catch() // Swallow errors, already logged
 
     return {
       requestModel,
@@ -410,36 +412,31 @@ export class DefaultProviderProxy {
       successStatus: response.status,
       responseHeaders,
       responseStream,
-      waitCompletion,
+      onStreamComplete,
     }
   }
 
-  private async processChunks<T>(modelAPI: BaseAPI<unknown, unknown, T>, events: AsyncIterable<T>): Promise<void> {
+  private async processChunks<T>(
+    modelAPI: BaseAPI<unknown, unknown, T>,
+    events: AsyncIterable<T>,
+  ): Promise<{ cost?: number } | { error: Error }> {
     for await (const chunk of events) {
       modelAPI.processChunk(chunk)
     }
 
-    this.otelSpan.end(
-      `chat ${modelAPI.extractedRequest?.requestModel ?? 'streaming'}`,
-      // TODO(Marcelo): Missing the HTTP attributes - Should we pass them around or store in ModelAPI?
-      { ...modelAPI.toGenAiOtelAttributes() },
-      { level: 'info' },
-    )
-
     const provider = this.usageProvider()
     const usage = modelAPI.extractedResponse.usage
     const responseModel = modelAPI.extractedResponse.responseModel
 
     if (!provider || !usage || !responseModel) {
-      logfire.warning('Unable to calculate cost', { provider, usage, responseModel })
+      return { error: new Error(`Unable to calculate cost for model ${responseModel}`) }
+    }
+
+    const price = calcPrice(usage, responseModel, { provider })
+    if (price) {
+      return { cost: price.total_price }
     } else {
-      const price = calcPrice(usage, responseModel, { providerId: this.providerId() })
-      if (price) {
-        this.cost = price.total_price
-        logfire.info('cost {cost}', { cost: this.cost, usage, responseModel })
-      } else {
-        logfire.warning('Unable to calculate cost', { provider, usage, responseModel })
-      }
+      return { error: new Error(`Unable to calculate cost for model ${responseModel} and provider ${provider.name}`) }
     }
   }
 
diff --git a/gateway/test/providers/anthropic.spec.ts.snap b/gateway/test/providers/anthropic.spec.ts.snap
index 92f6a56..f440728 100644
--- a/gateway/test/providers/anthropic.spec.ts.snap
+++ b/gateway/test/providers/anthropic.spec.ts.snap
@@ -1130,7 +1130,7 @@ exports[`anthropic > should call anthropic via gateway with stream > span 1`] =
   {
     "key": "logfire.json_schema",
     "value": {
-      "stringValue": "{"type":"object","properties":{"gen_ai.system":{"type":"string"},"gen_ai.operation.name":{"type":"string"},"gen_ai.request.model":{"type":"string"},"gen_ai.request.max_tokens":{"type":"number"},"gen_ai.response.model":{"type":"string"},"gen_ai.response.id":{"type":"string"},"gen_ai.usage.input_tokens":{"type":"number"},"gen_ai.usage.cache_read_tokens":{"type":"number"},"gen_ai.usage.cache_write_tokens":{"type":"number"},"gen_ai.usage.output_tokens":{"type":"number"}}}",
+      "stringValue": "{"type":"object","properties":{"gen_ai.system":{"type":"string"},"gen_ai.operation.name":{"type":"string"},"gen_ai.request.model":{"type":"string"},"gen_ai.request.max_tokens":{"type":"number"},"gen_ai.response.model":{"type":"string"},"gen_ai.response.id":{"type":"string"},"gen_ai.usage.input_tokens":{"type":"number"},"gen_ai.usage.cache_read_tokens":{"type":"number"},"gen_ai.usage.cache_write_tokens":{"type":"number"},"gen_ai.usage.output_tokens":{"type":"number"},"http.request.method":{"type":"string"},"url.full":{"type":"string"},"http.request.header.accept":{"type":"string"},"http.request.header.anthropic-version":{"type":"string"},"http.request.header.authorization":{"type":"string"},"http.request.header.content-type":{"type":"string"},"http.request.header.user-agent":{"type":"string"},"http.request.header.x-stainless-arch":{"type":"string"},"http.request.header.x-stainless-lang":{"type":"string"},"http.request.header.x-stainless-os":{"type":"string"},"http.request.header.x-stainless-package-version":{"type":"string"},"http.request.header.x-stainless-retry-count":{"type":"string"},"http.request.header.x-stainless-runtime":{"type":"string"},"http.request.header.x-stainless-runtime-version":{"type":"string"},"http.request.header.x-stainless-timeout":{"type":"string"},"http.response.status_code":{"type":"number"},"http.response.header.server":{"type":"string"},"http.response.header.transfer-encoding":{"type":"string"}}}",
     },
   },
   {
@@ -1199,5 +1199,113 @@ exports[`anthropic > should call anthropic via gateway with stream > span 1`] =
       "intValue": 10,
     },
   },
+  {
+    "key": "http.request.method",
+    "value": {
+      "stringValue": "POST",
+    },
+  },
+  {
+    "key": "url.full",
+    "value": {
+      "stringValue": "https://example.com/anthropic/v1/messages?beta=true",
+    },
+  },
+  {
+    "key": "http.request.header.accept",
+    "value": {
+      "stringValue": "application/json",
+    },
+  },
+  {
+    "key": "http.request.header.anthropic-version",
+    "value": {
+      "stringValue": "2023-06-01",
+    },
+  },
+  {
+    "key": "http.request.header.authorization",
+    "value": {
+      "stringValue": "Bearer healthy",
+    },
+  },
+  {
+    "key": "http.request.header.content-type",
+    "value": {
+      "stringValue": "application/json",
+    },
+  },
+  {
+    "key": "http.request.header.user-agent",
+    "value": {
+      "stringValue": "Anthropic/JS 0.62.0",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-arch",
+    "value": {
+      "stringValue": "unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-lang",
+    "value": {
+      "stringValue": "js",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-os",
+    "value": {
+      "stringValue": "Unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-package-version",
+    "value": {
+      "stringValue": "0.62.0",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-retry-count",
+    "value": {
+      "stringValue": "0",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-runtime",
+    "value": {
+      "stringValue": "unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-runtime-version",
+    "value": {
+      "stringValue": "unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-timeout",
+    "value": {
+      "stringValue": "600",
+    },
+  },
+  {
+    "key": "http.response.status_code",
+    "value": {
+      "intValue": 200,
+    },
+  },
+  {
+    "key": "http.response.header.server",
+    "value": {
+      "stringValue": "uvicorn",
+    },
+  },
+  {
+    "key": "http.response.header.transfer-encoding",
+    "value": {
+      "stringValue": "chunked",
+    },
+  },
 ]
 `;
diff --git a/gateway/test/providers/openai.spec.ts.snap b/gateway/test/providers/openai.spec.ts.snap
index c6c2b95..05f39f6 100644
--- a/gateway/test/providers/openai.spec.ts.snap
+++ b/gateway/test/providers/openai.spec.ts.snap
@@ -463,7 +463,7 @@ exports[`openai > openai chat stream > span 1`] = `
   {
     "key": "logfire.json_schema",
     "value": {
-      "stringValue": "{"type":"object","properties":{"gen_ai.system":{"type":"string"},"gen_ai.operation.name":{"type":"string"},"gen_ai.request.model":{"type":"string"},"gen_ai.request.max_tokens":{"type":"number"},"gen_ai.response.model":{"type":"string"},"gen_ai.response.id":{"type":"string"},"gen_ai.usage.input_tokens":{"type":"number"},"gen_ai.usage.cache_read_tokens":{"type":"number"},"gen_ai.usage.output_tokens":{"type":"number"},"gen_ai.usage.input_audio_tokens":{"type":"number"},"gen_ai.usage.output_audio_tokens":{"type":"number"}}}",
+      "stringValue": "{"type":"object","properties":{"gen_ai.system":{"type":"string"},"gen_ai.operation.name":{"type":"string"},"gen_ai.request.model":{"type":"string"},"gen_ai.request.max_tokens":{"type":"number"},"gen_ai.response.model":{"type":"string"},"gen_ai.response.id":{"type":"string"},"gen_ai.usage.input_tokens":{"type":"number"},"gen_ai.usage.cache_read_tokens":{"type":"number"},"gen_ai.usage.output_tokens":{"type":"number"},"gen_ai.usage.input_audio_tokens":{"type":"number"},"gen_ai.usage.output_audio_tokens":{"type":"number"},"http.request.method":{"type":"string"},"url.full":{"type":"string"},"http.request.header.accept":{"type":"string"},"http.request.header.authorization":{"type":"string"},"http.request.header.content-length":{"type":"string"},"http.request.header.content-type":{"type":"string"},"http.request.header.user-agent":{"type":"string"},"http.request.header.x-stainless-arch":{"type":"string"},"http.request.header.x-stainless-lang":{"type":"string"},"http.request.header.x-stainless-os":{"type":"string"},"http.request.header.x-stainless-package-version":{"type":"string"},"http.request.header.x-stainless-retry-count":{"type":"string"},"http.request.header.x-stainless-runtime":{"type":"string"},"http.request.header.x-stainless-runtime-version":{"type":"string"},"http.request.header.x-stainless-timeout":{"type":"string"},"http.response.status_code":{"type":"number"},"http.response.header.server":{"type":"string"},"http.response.header.transfer-encoding":{"type":"string"}}}",
     },
   },
   {
@@ -538,6 +538,114 @@ exports[`openai > openai chat stream > span 1`] = `
       "intValue": 0,
     },
   },
+  {
+    "key": "http.request.method",
+    "value": {
+      "stringValue": "POST",
+    },
+  },
+  {
+    "key": "url.full",
+    "value": {
+      "stringValue": "https://example.com/openai/chat/completions",
+    },
+  },
+  {
+    "key": "http.request.header.accept",
+    "value": {
+      "stringValue": "application/json",
+    },
+  },
+  {
+    "key": "http.request.header.authorization",
+    "value": {
+      "stringValue": "Bearer healthy",
+    },
+  },
+  {
+    "key": "http.request.header.content-length",
+    "value": {
+      "stringValue": "319",
+    },
+  },
+  {
+    "key": "http.request.header.content-type",
+    "value": {
+      "stringValue": "application/json",
+    },
+  },
+  {
+    "key": "http.request.header.user-agent",
+    "value": {
+      "stringValue": "OpenAI/JS 4.104.0",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-arch",
+    "value": {
+      "stringValue": "unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-lang",
+    "value": {
+      "stringValue": "js",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-os",
+    "value": {
+      "stringValue": "Unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-package-version",
+    "value": {
+      "stringValue": "4.104.0",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-retry-count",
+    "value": {
+      "stringValue": "0",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-runtime",
+    "value": {
+      "stringValue": "unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-runtime-version",
+    "value": {
+      "stringValue": "unknown",
+    },
+  },
+  {
+    "key": "http.request.header.x-stainless-timeout",
+    "value": {
+      "stringValue": "600",
+    },
+  },
+  {
+    "key": "http.response.status_code",
+    "value": {
+      "intValue": 200,
+    },
+  },
+  {
+    "key": "http.response.header.server",
+    "value": {
+      "stringValue": "uvicorn",
+    },
+  },
+  {
+    "key": "http.response.header.transfer-encoding",
+    "value": {
+      "stringValue": "chunked",
+    },
+  },
 ]
 `;
 
diff --git a/proxy-vcr/proxy_vcr/main.py b/proxy-vcr/proxy_vcr/main.py
index 0c03d2f..4cf10a0 100644
--- a/proxy-vcr/proxy_vcr/main.py
+++ b/proxy-vcr/proxy_vcr/main.py
@@ -110,7 +110,14 @@ async def health_check(_: Request) -> Response:
 
 if __name__ == '__main__':
     this_dir = pathlib.Path(__file__).parent
-    uvicorn.run('proxy_vcr.main:app', host='0.0.0.0', port=8005, reload=True, reload_dirs=[str(this_dir)])
+    uvicorn.run(
+        'proxy_vcr.main:app',
+        host='0.0.0.0',
+        port=8005,
+        reload=True,
+        reload_dirs=[str(this_dir)],
+        date_header=False,
+    )
 
 
 def cassette_name(provider: str, hash: str) -> str: