diff --git a/db/queries/inbox.sql b/db/queries/inbox.sql
index e2d98f9f..731e6c44 100644
--- a/db/queries/inbox.sql
+++ b/db/queries/inbox.sql
@@ -35,7 +35,7 @@ WHERE bot_id = sqlc.arg(bot_id)
 -- name: SearchInboxItems :many
 SELECT * FROM bot_inbox
 WHERE bot_id = sqlc.arg(bot_id)
-  AND content ILIKE '%' || sqlc.arg(query) || '%'
+  AND (sqlc.narg(query)::text IS NULL OR content ILIKE '%' || sqlc.narg(query)::text || '%')
   AND (sqlc.narg(start_time)::timestamptz IS NULL OR created_at >= sqlc.narg(start_time)::timestamptz)
   AND (sqlc.narg(end_time)::timestamptz IS NULL OR created_at <= sqlc.narg(end_time)::timestamptz)
   AND (sqlc.narg(include_read)::boolean IS NULL OR sqlc.narg(include_read)::boolean = TRUE OR is_read = FALSE)
diff --git a/internal/db/sqlc/inbox.sql.go b/internal/db/sqlc/inbox.sql.go
index 9e6a8dba..2ff9dddc 100644
--- a/internal/db/sqlc/inbox.sql.go
+++ b/internal/db/sqlc/inbox.sql.go
@@ -246,7 +246,7 @@ func (q *Queries) MarkInboxItemsRead(ctx context.Context, arg MarkInboxItemsRead
 const searchInboxItems = `-- name: SearchInboxItems :many
 SELECT id, bot_id, source, header, content, action, is_read, created_at, read_at FROM bot_inbox
 WHERE bot_id = $1
-  AND content ILIKE '%' || $2 || '%'
+  AND ($2::text IS NULL OR content ILIKE '%' || $2::text || '%')
   AND ($3::timestamptz IS NULL OR created_at >= $3::timestamptz)
   AND ($4::timestamptz IS NULL OR created_at <= $4::timestamptz)
   AND ($5::boolean IS NULL OR $5::boolean = TRUE OR is_read = FALSE)
diff --git a/internal/inbox/service.go b/internal/inbox/service.go
index 88675cd9..9f1d3633 100644
--- a/internal/inbox/service.go
+++ b/internal/inbox/service.go
@@ -198,7 +198,7 @@ func (s *Service) Search(ctx context.Context, botID string, req SearchRequest) (
 	}
 	params := sqlc.SearchInboxItemsParams{
 		BotID:    botUUID,
-		Query:    pgtype.Text{String: req.Query, Valid: true},
+		Query:    textOrNull(req.Query),
 		MaxCount: int32(limit),
 	}
 	if req.StartTime != nil {
diff --git a/internal/mcp/providers/inbox/provider.go b/internal/mcp/providers/inbox/provider.go
index 443f6fdd..3f569e41 100644
--- a/internal/mcp/providers/inbox/provider.go
+++ b/internal/mcp/providers/inbox/provider.go
@@ -65,7 +65,7 @@ func (e *Executor) ListTools(ctx context.Context, session mcpgw.ToolSessionConte
 						"description": "Whether to include already-read items (default true)",
 					},
 				},
-				"required": []string{"query"},
+				"required": []string{},
 			},
 		},
 	}, nil
@@ -80,9 +80,6 @@ func (e *Executor) CallTool(ctx context.Context, session mcpgw.ToolSessionContex
 	}
 
 	query := mcpgw.StringArg(arguments, "query")
-	if query == "" {
-		return mcpgw.BuildToolErrorResult("query is required"), nil
-	}
 	botID := strings.TrimSpace(session.BotID)
 	if botID == "" {
 		return mcpgw.BuildToolErrorResult("bot_id is required"), nil