[docs] Update documentation for allowed-extensions default behavior

docs/src/content/docs/reference/frontmatter-full.md

@@ -1517,8 +1517,8 @@ tools:
     # (optional)
     scope: "workflow"
 
-    # List of allowed file extensions (e.g., [".json", ".txt"]). Default: [".json",
-    # ".jsonl", ".txt", ".md", ".csv"]
+    # List of allowed file extensions (e.g., [".json", ".txt"]). Default: [] (empty/all
+    # files allowed). When specified, only files with listed extensions can be stored.
     # (optional)
     allowed-extensions: []
       # Array of strings
@@ -1720,8 +1720,8 @@ tools:
     # (optional)
     create-orphan: true
 
-    # List of allowed file extensions (e.g., [".json", ".txt"]). Default: [".json",
-    # ".jsonl", ".txt", ".md", ".csv"]
+    # List of allowed file extensions (e.g., [".json", ".txt"]). Default: [] (empty/all
+    # files allowed). When specified, only files with listed extensions can be stored.
     # (optional)
     allowed-extensions: []
       # Array of strings

docs/src/content/docs/reference/memory.md

@@ -30,9 +30,24 @@ tools:
   cache-memory:
     key: custom-memory-${{ github.workflow }}-${{ github.run_id }}
     retention-days: 30  # 1-90 days, extends access beyond cache expiration
+    allowed-extensions: [".json", ".txt", ".md"]  # Restrict file types (default: empty/all files allowed)
 ---
 ```
 
+### File Type Restrictions
+
+The `allowed-extensions` field restricts which file types can be written to cache-memory. By default, all file types are allowed (empty array). When specified, only files with listed extensions can be stored.
+
+```aw wrap
+---
+tools:
+  cache-memory:
+    allowed-extensions: [".json", ".jsonl", ".txt"]  # Only these extensions allowed
+---
+```
+
+If files with disallowed extensions are found, the workflow will report validation failures.
+
 ## Multiple Cache Configurations
 
 ```aw wrap
@@ -118,11 +133,14 @@ tools:
     max-file-count: 50      # default 100
     target-repo: "owner/repository"
     create-orphan: true     # default
+    allowed-extensions: [".json", ".txt", ".md"]  # Restrict file types (default: empty/all files allowed)
 ---
 ```
 
 **Branch Prefix**: Use `branch-prefix` to customize the branch name prefix (default is `memory`). The prefix must be 4-32 characters, alphanumeric with hyphens/underscores, and cannot be `copilot`. When set, branches are created as `{branch-prefix}/{id}` instead of `memory/{id}`.
 
+**File Type Restrictions**: Use `allowed-extensions` to restrict which file types can be stored (default: empty/all files allowed). When specified, only files with listed extensions (e.g., `[".json", ".txt", ".md"]`) can be saved. Files with disallowed extensions will trigger validation failures.
+
 **Note**: File glob patterns must include the full branch path structure. For branch `memory/custom-agent-for-aw`, use patterns like `memory/custom-agent-for-aw/*.json` to match files stored at that path within the branch.
 
 ## Multiple Repo Memory Configurations