feat(logging): add log line formatter

src/grist_mcp/logging.py

@@ -1,5 +1,7 @@
 """Logging configuration and utilities."""
 
+from datetime import datetime
+
 
 def extract_stats(tool_name: str, arguments: dict, result: dict) -> str:
     """Extract meaningful stats from tool call based on tool type."""
@@ -53,3 +55,29 @@ def truncate_token(token: str) -> str:
     if len(token) <= 8:
         return "***"
     return f"{token[:3]}...{token[-3:]}"
+
+
+def format_tool_log(
+    agent_name: str,
+    token: str,
+    tool: str,
+    document: str | None,
+    stats: str,
+    status: str,
+    duration_ms: int,
+    error_message: str | None = None,
+) -> str:
+    """Format a tool call log line.
+
+    Format: YYYY-MM-DD HH:MM:SS | agent (token) | tool | doc | stats | status | duration
+    """
+    timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
+    truncated = truncate_token(token)
+    doc = document if document else "-"
+
+    line = f"{timestamp} | {agent_name} ({truncated}) | {tool} | {doc} | {stats} | {status} | {duration_ms}ms"
+
+    if error_message:
+        line += f"\n    {error_message}"
+
+    return line