diff --git a/src/services/api/openaiShim/requestExecutor.test.ts b/src/services/api/openaiShim/requestExecutor.test.ts
index 9d3e05918e..742c9e86d3 100644
--- a/src/services/api/openaiShim/requestExecutor.test.ts
+++ b/src/services/api/openaiShim/requestExecutor.test.ts
@@ -758,6 +758,40 @@ test('raw-env LLMTR ignores unsupported custom auth and custom headers', async (
   expect(captured.headers['X-Tenant-Secret']).toBeUndefined()
 })
 
+test('OpenCode Go sends the required stable session and user-agent headers', async () => {
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_BASE_URL = 'https://opencode.ai/zen/go/v1'
+  process.env.OPENAI_MODEL = 'glm-5.1'
+  process.env.OPENCODE_API_KEY = 'opencode-key'
+  delete process.env.OPENAI_API_KEY
+  delete process.env.OPENAI_API_KEYS
+
+  const captured = await captureChatCompletionRequest('glm-5.1', {
+    'x-opencode-session': 'caller-session',
+    'User-Agent': 'caller-agent',
+  })
+
+  expect(captured.headers['x-opencode-session']).toMatch(
+    /^[0-9a-f-]{36}$/,
+  )
+  expect(captured.headers['User-Agent']).toMatch(/^openclaude\//)
+  expect(captured.headers['x-opencode-session']).not.toBe('caller-session')
+  expect(captured.headers['User-Agent']).not.toBe('caller-agent')
+})
+
+test('OpenCode Zen does not receive the OpenCode Go session header', async () => {
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_BASE_URL = 'https://opencode.ai/zen/v1'
+  process.env.OPENAI_MODEL = 'gpt-5.4'
+  process.env.OPENCODE_API_KEY = 'opencode-key'
+  delete process.env.OPENAI_API_KEY
+  delete process.env.OPENAI_API_KEYS
+
+  const captured = await captureChatCompletionRequest('gpt-5.4')
+
+  expect(captured.headers['x-opencode-session']).toBeUndefined()
+})
+
 test('custom endpoints preserve configured auth and custom headers', async () => {
   process.env.CLAUDE_CODE_USE_OPENAI = '1'
   process.env.OPENAI_BASE_URL = 'https://proxy.example/v1'
diff --git a/src/services/api/openaiShim/requestExecutor.ts b/src/services/api/openaiShim/requestExecutor.ts
index 373c70b54c..7910fb2f35 100644
--- a/src/services/api/openaiShim/requestExecutor.ts
+++ b/src/services/api/openaiShim/requestExecutor.ts
@@ -1,6 +1,7 @@
 import type { CredentialLease, CredentialPool } from '../credentialPool.js'
 import type { OpenAICompatibilityFailure } from '../openaiErrorClassification.js'
 import type { OpenAIShimRuntimeContext } from '../../../integrations/runtimeMetadata.js'
+import { resolveRouteIdFromBaseUrl } from '../../../integrations/routeMetadata.js'
 import { getCommandcodeChatCompletionsModelError } from '../../../integrations/gateways/commandcode.js'
 import {
   redactEncodedSecretSubstringsForDisplay,
@@ -295,7 +296,10 @@ export async function executeOpenAIRequest(
   const isXaiRoute =
     runtimeShimContext.routeId === 'xai' || isXaiBaseUrl(request.baseUrl)
   const openCodeGoSessionId =
-    runtimeShimContext.routeId === 'opencode-go' ? getSessionId() : null
+    (runtimeShimContext.routeId === 'opencode-go' ||
+      resolveRouteIdFromBaseUrl(request.baseUrl) === 'opencode-go')
+      ? getSessionId()
+      : null
   const openAIApiKeysPoolRaw =
     routeAcceptsGenericOpenAICredentials &&
     parseCredentialList(requestProcessEnv.OPENAI_API_KEYS).length > 0