fix: casefold repo-binding keys to avoid spurious cross-repo mismatch

GitHub owner/name are case-insensitive. Casefold the owner/name key on both the
write (binding) and read (compare) sides — repo_cache_key and the metadata
bound_repo read — so Org/Repo and org/repo resolve to one repo and a legitimate
same-repo run cannot raise a spurious SandboxRepoMismatchError (Gap 2).

agent/utils/github_token.py

@@ -28,15 +28,20 @@ class GitHubAuthError(Exception):
 
 
 def repo_cache_key(repo: Any) -> str | None:
-    """Normalize a repo dict/string to ``owner/name`` (None when unknown)."""
+    """Normalize a repo dict/string to a casefolded ``owner/name`` (None if unknown).
+
+    GitHub owner/name are case-insensitive, so the key is casefolded on both the
+    write (binding) and read (compare) sides to keep ``Org/Repo`` and ``org/repo``
+    a single repo and avoid spurious cross-repo mismatches.
+    """
     if isinstance(repo, str):
         cleaned = repo.strip()
-        return cleaned or None
+        return cleaned.casefold() or None
     if isinstance(repo, Mapping):
         owner = repo.get("owner")
         name = repo.get("name")
         if isinstance(owner, str) and isinstance(name, str) and owner and name:
-            return f"{owner}/{name}"
+            return f"{owner}/{name}".casefold()
     return None
 
 

agent/utils/sandbox_state.py

@@ -19,6 +19,7 @@ from deepagents.backends.protocol import (
 )
 from langgraph.config import get_config
 
+from .github_token import repo_cache_key
 from .sandbox import create_sandbox
 
 logger = logging.getLogger(__name__)
@@ -167,7 +168,9 @@ async def get_bound_repo_from_metadata(thread_id: str) -> str | None:
     if not isinstance(metadata, dict):
         return None
     bound_repo = metadata.get("bound_repo")
-    return bound_repo if isinstance(bound_repo, str) and bound_repo else None
+    # Casefold on read so legacy metadata written before normalization (e.g.
+    # ``Org/Repo``) still compares equal to the casefolded current repo key.
+    return repo_cache_key(bound_repo) if isinstance(bound_repo, str) and bound_repo else None
 
 
 def clear_sandbox_backend(thread_id: str) -> None: