diff --git a/.changeset/fix-stagehand-project-id-docs.md b/.changeset/fix-stagehand-project-id-docs.md
new file mode 100644
index 000000000..00a9eef94
--- /dev/null
+++ b/.changeset/fix-stagehand-project-id-docs.md
@@ -0,0 +1,5 @@
+---
+"@browserbasehq/stagehand-server-v3": patch
+---
+
+Mark the deprecated Browserbase project ID header as optional in generated API docs.
diff --git a/packages/server-v3/openapi.v3.yaml b/packages/server-v3/openapi.v3.yaml
index 4b82d6d56..617c707ec 100644
--- a/packages/server-v3/openapi.v3.yaml
+++ b/packages/server-v3/openapi.v3.yaml
@@ -2313,4 +2313,3 @@ servers:
   - url: https://api.stagehand.browserbase.com
 security:
   - BrowserbaseApiKey: []
-    BrowserbaseProjectId: []
diff --git a/packages/server-v3/scripts/gen-openapi.ts b/packages/server-v3/scripts/gen-openapi.ts
index 6e3f02524..7d71ea01e 100644
--- a/packages/server-v3/scripts/gen-openapi.ts
+++ b/packages/server-v3/scripts/gen-openapi.ts
@@ -145,7 +145,7 @@ Please try it and give us your feedback, stay tuned for upcoming release announc
         securitySchemes: Api.openApiSecuritySchemes,
         links: Api.openApiLinks,
       },
-      security: [{ BrowserbaseApiKey: [], BrowserbaseProjectId: [] }],
+      security: [{ BrowserbaseApiKey: [] }],
     },
     ...fastifyZodOpenApiTransformers,
   });
diff --git a/stainless.yml b/stainless.yml
index c8bf766ab..a791e8541 100644
--- a/stainless.yml
+++ b/stainless.yml
@@ -231,8 +231,7 @@ client_settings:
       read_env: BROWSERBASE_PROJECT_ID
       description: Deprecated. Browserbase API keys are now project-scoped, so this value is no longer required.
       nullable: true
-      auth:
-        security_scheme: BBProjectIdAuth
+      send_in_header: x-bb-project-id
     MODEL_API_KEY:
       type: string
       read_env: MODEL_API_KEY
@@ -246,10 +245,6 @@ security_schemes:
     type: apiKey
     in: header
     name: x-bb-api-key
-  BBProjectIdAuth:
-    type: apiKey
-    in: header
-    name: x-bb-project-id
   LLMModelApiKeyAuth:
     type: apiKey
     in: header
@@ -257,7 +252,6 @@ security_schemes:
 
 security:
   - BBApiKeyAuth: []
-    BBProjectIdAuth: []
     LLMModelApiKeyAuth: []
 
 # `readme` is used to configure the code snippets that will be rendered in the