diff --git a/agent/prompt.py b/agent/prompt.py
index 744935f99..295c1aebd 100644
--- a/agent/prompt.py
+++ b/agent/prompt.py
@@ -135,6 +135,7 @@ def _load_default_prompt() -> str:
 
 #### `http_request`
 Make HTTP requests (GET, POST, PUT, DELETE, etc.) to APIs. Use this for API calls with custom headers, methods, params, or request bodies — not for fetching web pages.
+**Do NOT use this tool to create, update, or otherwise manage GitHub pull requests.** This tool sends no GitHub authentication and will receive a 401 Unauthorized from the GitHub API. Always use `commit_and_open_pr` for GitHub PR operations.
 
 #### `commit_and_open_pr`
 Commits all changes, pushes to a branch, and opens a **draft** GitHub PR. If a PR already exists for the branch, it is updated instead of recreated.
diff --git a/agent/tools/http_request.py b/agent/tools/http_request.py
index 942faba8d..471db48f9 100644
--- a/agent/tools/http_request.py
+++ b/agent/tools/http_request.py
@@ -107,6 +107,10 @@ def http_request(
 ) -> dict[str, Any]:
     """Make HTTP requests to APIs and web services.
 
+    Do NOT use this tool to create, update, or otherwise manage GitHub pull requests —
+    always use the `commit_and_open_pr` tool for that. This tool sends no GitHub
+    authentication and will receive a 401 Unauthorized response from the GitHub API.
+
     Args:
         url: Target URL
         method: HTTP method (GET, POST, PUT, DELETE, etc.)