diff --git a/bugbug/tools/code_review/database.py b/bugbug/tools/code_review/database.py
index 6320e26978..4f19b7c092 100644
--- a/bugbug/tools/code_review/database.py
+++ b/bugbug/tools/code_review/database.py
@@ -135,7 +135,7 @@ class EvaluationAction(enum.Enum):
 
 @dataclass
 class SuggestionFeedback:
-    id: int
+    id: int | str
     comment: str
     file_path: str
     action: Literal["APPROVE", "REJECT", "IGNORE"]
diff --git a/bugbug/tools/code_review/langchain_tools.py b/bugbug/tools/code_review/langchain_tools.py
index a6b2b0bbc0..71985712c9 100644
--- a/bugbug/tools/code_review/langchain_tools.py
+++ b/bugbug/tools/code_review/langchain_tools.py
@@ -203,7 +203,7 @@ async def search_text(
     except SearchfoxNetworkError as e:
         return _tool_error(f"search failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request searching for %r (path=%r, langs=%r): %s",
             query,
             path_filter,
@@ -233,7 +233,7 @@ async def get_field_layout(
     except SearchfoxNetworkError as e:
         return _tool_error(f"field layout fetch failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error("Bad request fetching field layout for %r: %s", class_name, e)
+        logger.warning("Bad request fetching field layout for %r: %s", class_name, e)
         return _tool_error(f"field layout fetch failed: {e}")
     except Exception as e:
         logger.error("Unexpected error fetching field layout for %r: %s", class_name, e)
@@ -265,7 +265,7 @@ async def get_blame(
     except SearchfoxNetworkError as e:
         return _tool_error(f"blame fetch failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request fetching blame for %r lines %r: %s", file_path, lines, e
         )
         return _tool_error(f"blame fetch failed: {e}")
@@ -304,7 +304,7 @@ async def check_can_gc(
     except SearchfoxNetworkError as e:
         return _tool_error(f"GC check failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error("Bad request checking GC status for %r: %s", symbol, e)
+        logger.warning("Bad request checking GC status for %r: %s", symbol, e)
         return _tool_error(f"GC check failed: {e}")
     except Exception as e:
         logger.error("Unexpected error checking GC status for %r: %s", symbol, e)
@@ -333,7 +333,7 @@ async def find_definition(
     except SearchfoxNetworkError as e:
         return _tool_error(f"definition lookup failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request finding definition for %r (path=%r): %s", name, path_filter, e
         )
         return _tool_error(f"definition lookup failed: {e}")
@@ -376,7 +376,7 @@ async def search_identifier(
     except SearchfoxNetworkError as e:
         return _tool_error(f"identifier search failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request searching for identifier %r (path=%r, langs=%r): %s",
             identifier,
             path_filter,
@@ -408,7 +408,7 @@ async def calls_from(
     except SearchfoxNetworkError as e:
         return _tool_error(f"call graph fetch failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request fetching calls from %r (depth=%d): %s", symbol, depth, e
         )
         return _tool_error(f"call graph fetch failed: {e}")
@@ -436,7 +436,7 @@ async def calls_to(
     except SearchfoxNetworkError as e:
         return _tool_error(f"call graph fetch failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request fetching calls to %r (depth=%d): %s", symbol, depth, e
         )
         return _tool_error(f"call graph fetch failed: {e}")
@@ -468,7 +468,7 @@ async def calls_between(
     except SearchfoxNetworkError as e:
         return _tool_error(f"call graph fetch failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request fetching calls between %r and %r (depth=%d): %s",
             symbol_a,
             symbol_b,
@@ -508,7 +508,7 @@ async def get_function_at_line(
     except SearchfoxNetworkError as e:
         return _tool_error(f"function lookup failed: {e}")
     except SearchfoxRequestError as e:
-        logger.error(
+        logger.warning(
             "Bad request fetching function at line %d in %r: %s", line, file_path, e
         )
         return _tool_error(f"function lookup failed: {e}")
diff --git a/bugbug/tools/core/platforms/bugzilla.py b/bugbug/tools/core/platforms/bugzilla.py
index 7096d7c783..bdd157eb78 100644
--- a/bugbug/tools/core/platforms/bugzilla.py
+++ b/bugbug/tools/core/platforms/bugzilla.py
@@ -10,6 +10,7 @@
 from datetime import datetime, timezone
 from functools import cached_property
 
+import requests
 from libmozdata.bugzilla import Bugzilla, BugzillaBase, BugzillaUser
 from libmozdata.config import set_default_value
 
@@ -18,6 +19,22 @@
 logger = logging.getLogger(__name__)
 
 EDITBUGS_GROUP_ID = 9
+
+
+class BugNotFoundError(ValueError):
+    pass
+
+
+class BugzillaAPIError(IOError):
+    pass
+
+
+class BugzillaTransientError(BugzillaAPIError):
+    """Transient error from the Bugzilla API (5xx or unexpected response format)."""
+
+    pass
+
+
 TRUST_BEFORE_DATE = datetime(2022, 1, 1, tzinfo=timezone.utc)
 
 REDACTED_TITLE = "[Unvalidated bug title redacted for security]"
@@ -418,15 +435,28 @@ def __getattr__(self, name: str):
     @classmethod
     def get(cls, bug_id: int, allow_private: bool = False) -> "Bug":
         bugs: list[dict] = []
-        Bugzilla(
-            bug_id,
-            include_fields=["_default", "comments", "history"],
-            bughandler=lambda bug, data: data.append(bug),
-            bugdata=bugs,
-        ).get_data().wait()
+        try:
+            Bugzilla(
+                bug_id,
+                include_fields=["_default", "comments", "history"],
+                bughandler=lambda bug, data: data.append(bug),
+                bugdata=bugs,
+            ).get_data().wait()
+        except requests.HTTPError as e:
+            if e.response is not None and e.response.status_code >= 500:
+                raise BugzillaTransientError(
+                    f"Bugzilla API error for bug {bug_id}: {e}"
+                ) from e
+            raise BugzillaAPIError(f"Bugzilla API error for bug {bug_id}: {e}") from e
+        except KeyError as e:
+            raise BugzillaTransientError(
+                f"Unexpected Bugzilla API response for bug {bug_id}: {e}"
+            ) from e
 
         if not bugs or (not allow_private and bugs[0]["groups"]):
-            raise ValueError(f"Bug {bug_id} not found")
+            raise BugNotFoundError(
+                f"Bug {bug_id} was not found. It may not exist or may be a confidential security bug."
+            )
 
         bug_data = bugs[0]
         assert bug_data["id"] == bug_id
diff --git a/bugbug/vectordb.py b/bugbug/vectordb.py
index fa499166b5..f3882978d3 100644
--- a/bugbug/vectordb.py
+++ b/bugbug/vectordb.py
@@ -23,8 +23,8 @@ class VectorPoint:
 
 @dataclass(order=True)
 class PayloadScore:
-    score: int
-    id: int
+    score: float
+    id: int | str
     payload: dict
 
 
@@ -134,9 +134,10 @@ def search(
     ) -> Iterable[PayloadScore]:
         qdrant_filter = filter.to_qdrant_filter() if filter else None
 
-        for item in self.client.search(
-            self.collection_name, query, qdrant_filter, limit=limit
-        ):
+        response = self.client.query_points(
+            self.collection_name, query=query, query_filter=qdrant_filter, limit=limit
+        )
+        for item in response.points:
             yield PayloadScore(item.score, item.id, item.payload)
 
     def get_existing_ids(self) -> Iterable[int]:
diff --git a/services/mcp/src/bugbug_mcp/__init__.py b/services/mcp/src/bugbug_mcp/__init__.py
index 720ed0485c..d17591d6d2 100644
--- a/services/mcp/src/bugbug_mcp/__init__.py
+++ b/services/mcp/src/bugbug_mcp/__init__.py
@@ -3,6 +3,9 @@
 
 import sentry_sdk
 
+from bugbug.tools.core.platforms.bugzilla import BugNotFoundError
+from bugbug_mcp.exceptions import InvalidDocPathError, RevisionNotFoundError
+
 __version__ = "0.1.0"
 
 
@@ -15,4 +18,5 @@
     # Add data like request headers and IP for users,
     # see https://docs.sentry.io/platforms/python/data-management/data-collected/ for more info
     send_default_pii=True,
+    ignore_errors=[BugNotFoundError, RevisionNotFoundError, InvalidDocPathError],
 )
diff --git a/services/mcp/src/bugbug_mcp/exceptions.py b/services/mcp/src/bugbug_mcp/exceptions.py
new file mode 100644
index 0000000000..a00d8190e8
--- /dev/null
+++ b/services/mcp/src/bugbug_mcp/exceptions.py
@@ -0,0 +1,9 @@
+from fastmcp.exceptions import ToolError
+
+
+class RevisionNotFoundError(ToolError):
+    pass
+
+
+class InvalidDocPathError(ToolError):
+    pass
diff --git a/services/mcp/src/bugbug_mcp/server.py b/services/mcp/src/bugbug_mcp/server.py
index a61cf2f9a8..335a37f8ad 100644
--- a/services/mcp/src/bugbug_mcp/server.py
+++ b/services/mcp/src/bugbug_mcp/server.py
@@ -8,7 +8,6 @@
 
 import httpx
 from fastmcp import FastMCP
-from fastmcp.exceptions import ToolError
 from fastmcp.resources import FileResource
 from pydantic import Field
 
@@ -18,6 +17,7 @@
     PhabricatorPatch,
     SanitizedPhabricatorPatch,
 )
+from bugbug_mcp.exceptions import InvalidDocPathError, RevisionNotFoundError
 
 mcp = FastMCP("Firefox Development MCP Server")
 
@@ -146,7 +146,7 @@ def bughandler(bug):
 def _get_revision_md(revision_id: int) -> str:
     patch = SanitizedPhabricatorPatch(revision_id=revision_id)
     if not patch.is_accessible() or not patch.is_public():
-        raise ToolError(
+        raise RevisionNotFoundError(
             f"Revision D{revision_id} was not found. It may not exist or may be private."
         )
     return patch.to_md()
@@ -187,7 +187,7 @@ async def read_fx_doc_section(
 ) -> str:
     """Retrieve the content of a section from Firefox Source Tree Documentation."""
     if not doc_path.endswith(".md") and not doc_path.endswith(".rst"):
-        raise ToolError(
+        raise InvalidDocPathError(
             f"Invalid path: {doc_path}. Path must end with `.rst` or `.md`. Use the docs://llms.txt resource on this MCP to find valid paths."
         )
 
@@ -196,7 +196,7 @@ async def read_fx_doc_section(
     async with httpx.AsyncClient() as client:
         response = await client.get(url)
         if response.status_code == 404:
-            raise ToolError(
+            raise InvalidDocPathError(
                 f"Invalid path: {doc_path}. Use the docs://llms.txt resource on this MCP to find valid paths."
             )
 
diff --git a/services/reviewhelper-api/app/routers/request.py b/services/reviewhelper-api/app/routers/request.py
index e3ba4578b8..044050a534 100644
--- a/services/reviewhelper-api/app/routers/request.py
+++ b/services/reviewhelper-api/app/routers/request.py
@@ -5,6 +5,7 @@
 from fastapi import APIRouter, Depends, status
 from fastapi.responses import JSONResponse
 from sqlalchemy import select
+from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.auth import verify_external_api_key
@@ -80,7 +81,19 @@ async def create_or_get_review_request(
         status=ReviewStatus.PENDING,
     )
     db.add(review_request)
-    await db.commit()
+    try:
+        await db.commit()
+    except IntegrityError:
+        await db.rollback()
+        existing_request = await db.scalar(stmt)
+        if existing_request is None:
+            raise
+        return JSONResponse(
+            {
+                "status": existing_request.status.value,
+                "message": _build_response_message(existing_request),
+            }
+        )
 
     schedule_time = (
         request.revision_created_at + INITIAL_TASK_DELAY