feat: add supports_parallel_tool_calls for MCP servers (#26825) — port to tool_dispatch_helpers

Original commit 395e9dd9e by Teknium targeted module-level _is_mcp_tool_parallel_safe
and _should_parallelize_tool_batch helpers in pre-refactor run_agent.py. Both
helpers now live in agent/tool_dispatch_helpers.py — re-applied to that
module.

The tools/mcp_tool.py portion (the public is_mcp_tool_parallel_safe API
+ _parallel_safe_servers tracking) merged cleanly from main via the prior
merge commit.

Co-authored-by: Teknium <127238744+teknium1@users.noreply.github.com>

agent/tool_dispatch_helpers.py

@@ -87,6 +87,19 @@ def _is_destructive_command(cmd: str) -> bool:
     return False
 
 
+def _is_mcp_tool_parallel_safe(tool_name: str) -> bool:
+    """Check if an MCP tool comes from a server with parallel tool calls enabled.
+
+    Lazy-imports from ``tools.mcp_tool`` to avoid circular dependencies.
+    Returns False if the MCP module is not available.
+    """
+    try:
+        from tools.mcp_tool import is_mcp_tool_parallel_safe
+        return is_mcp_tool_parallel_safe(tool_name)
+    except Exception:
+        return False
+
+
 def _should_parallelize_tool_batch(tool_calls) -> bool:
     """Return True when a tool-call batch is safe to run concurrently."""
     if len(tool_calls) <= 1:
@@ -126,7 +139,9 @@ def _should_parallelize_tool_batch(tool_calls) -> bool:
             continue
 
         if tool_name not in _PARALLEL_SAFE_TOOLS:
-            return False
+            # Check if it's an MCP tool from a server that opted into parallel calls.
+            if not _is_mcp_tool_parallel_safe(tool_name):
+                return False
 
     return True