Harness spec 3.3.0: subagents — the word, the model, capacity, the offer

- "Subagent" in every text a person or a model reads; "helper" retired
  (the team area's step helper_done is now task_done).
- A subagent runs on the session's model unless the person named another
  in this session's own messages; task's and team_add's `model` is refused
  otherwise. No setting chooses a subagent's model.
- Capacity: another model on the session's model's one-model server is
  refused; the session's model as its own subagent needs parallel >= 2 or
  no limit; no fallback.
- The agents {min, max} setting is shown as Subagents, offered when a model
  could serve; context.note.team_own when the session's model cannot.
- subagents.md, loop.json subagents, conformance/subagents.json (26 cases).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

harness/tools/team_add.json

@@ -47,7 +47,7 @@
       },
       "model": {
         "type": "string",
-        "description": "Run it on another model you may use (from the list in your instructions). Default: yours."
+        "description": "Run it on another model — only one the person named in this conversation (its id or name, as in the list in your instructions). Default: the session's model."
       }
     },
     "required": [