fix(client): strip api-key and OpenAI org/project headers before forwarding

crates/libsy-llm-client/src/client.rs

@@ -26,12 +26,11 @@ use crate::error::{LlmClientError, Result};
 use crate::metrics;
 use crate::raw::RawResponse;
 
-// TODO: Why is this here? What does it do?
 // Headers this client owns or that are hop-by-hop; never forwarded from the
-// caller's metadata. Auth/version/content-type are set by the backend or the
-// JSON body, so a forwarded copy would either be ignored or conflict. Compared
-// case-insensitively. Aligns with `_SENSITIVE_HEADERS` in the Python
-// `switchyard/lib/request_metadata.py` forwarding logic.
+// caller's metadata. Auth, credential, and tenant-selector headers are set by
+// the backend (via `apply_auth` or configured `extra_headers`), so a forwarded
+// client copy would either be ignored or conflict with, and in some cases
+// override, the backend's own value. Compared case-insensitively.
 const RESERVED_HEADERS: &[&str] = &[
     "host",
     "content-length",
@@ -42,6 +41,13 @@ const RESERVED_HEADERS: &[&str] = &[
     "cookie",
     "set-cookie",
     "x-api-key",
+    // `api-key` is Azure OpenAI's credential header (the `x-`-less sibling of
+    // `x-api-key`); `openai-organization` and `openai-project` select the
+    // billing tenant for the backend's key. A caller must not be able to set
+    // any of these on the upstream request.
+    "api-key",
+    "openai-organization",
+    "openai-project",
     "anthropic-beta",
     "anthropic-version",
     "content-type",
@@ -1813,6 +1819,60 @@ mod tests {
         Ok(())
     }
 
+    #[tokio::test]
+    async fn strips_client_credential_and_tenant_headers()
+    -> std::result::Result<(), Box<dyn Error + Sync + Send + 'static>> {
+        let server = MockServer::start().await;
+        Mock::given(method("POST"))
+            // The backend bearer is preserved and none of the client's
+            // credential or tenant-selector headers reach the upstream.
+            .and(wiremock::matchers::header("authorization", "Bearer secret"))
+            .respond_with(ResponseTemplate::new(200).set_body_json(json!({
+                "id": "1", "model": "gpt",
+                "choices": [{"index": 0, "message": {"role": "assistant", "content": "ok"}, "finish_reason": "stop"}],
+                "usage": {}
+            })))
+            .mount(&server)
+            .await;
+
+        let mut headers = http::HeaderMap::new();
+        headers.insert(
+            "api-key",
+            http::HeaderValue::from_static("client-azure-key"),
+        );
+        headers.insert(
+            "openai-organization",
+            http::HeaderValue::from_static("org-client"),
+        );
+        headers.insert(
+            "openai-project",
+            http::HeaderValue::from_static("proj-client"),
+        );
+        let request = Request {
+            llm_request: LlmRequest {
+                model: Some("gpt".to_string()),
+                ..LlmRequest::default()
+            },
+            raw_request: None,
+            metadata: Some(Metadata {
+                http_headers: Some(headers),
+                ..Default::default()
+            }),
+        };
+
+        let client = TranslatingLlmClient::new(&chat_map(&format!("{}/v1", server.uri())))?;
+        client.call_rewrite_model(request, None).await?;
+        let received = server
+            .received_requests()
+            .await
+            .ok_or("request recording should be enabled")?;
+        let received = received.first().ok_or("expected one upstream request")?;
+        assert!(!received.headers.contains_key("api-key"));
+        assert!(!received.headers.contains_key("openai-organization"));
+        assert!(!received.headers.contains_key("openai-project"));
+        Ok(())
+    }
+
     // Exercises the `RoutedLlmClient` impl: `call` uses the model already materialized in the
     // request and round-trips a buffered response.
     #[tokio::test]