diff --git a/docs/SYNC_BEHAVIOR.md b/docs/SYNC_BEHAVIOR.md
index 684e1c3..df9ca1e 100644
--- a/docs/SYNC_BEHAVIOR.md
+++ b/docs/SYNC_BEHAVIOR.md
@@ -66,13 +66,25 @@ Full Sync of Tickets (last 2 years):
 - Requires a previous successful sync to establish baseline
 - Falls back to full sync if no previous sync found
 
+**Important Limitations:**
+- **Companies and Resources** do NOT support incremental sync
+  - These entities automatically fall back to full sync
+  - Autotask API does not support date-based filtering for these entities
+  - This is by design and prevents sync failures
+
 **Example:**
 ```
-Incremental Sync of Companies:
+Incremental Sync of Tickets:
 1. Get last sync time: 2026-01-24 08:00:00
-2. Fetch companies where lastModifiedDate >= 2026-01-24 08:00:00
-3. Upsert only the changed companies
+2. Fetch tickets where lastActivityDate >= 2026-01-24 08:00:00
+3. Upsert only the changed tickets
 4. No soft deletes
+
+Incremental Sync of Companies (automatic fallback):
+1. Request incremental sync
+2. System detects Companies doesn't support incremental
+3. Automatically performs full sync instead
+4. Logs: "companies does not support incremental sync, performing full sync instead"
 ```
 
 ### Sync Selected (Entity-Specific)