| Expecting subagents to spawn sub-subagents | Subagents cannot nest; chain subagents from the main conversation instead |
| Giving Bash tool to agents that only create files | Use Write and Edit tools only; Bash causes approval spam from heredoc usage |
Omitting disallowedTools for sensitive operations | Use disallowedTools to explicitly deny dangerous tools even when inheriting |
| Spawning too many agents (5+) for a small task | Start with 2-3 agents; coordination overhead outweighs benefit at higher counts |
| Burying critical instructions past line 300 of agent prompt | Put critical rules immediately after frontmatter; models deprioritize late instructions |
| Using specialized agents for large-scale software dev | Use fungible agents with a shared task board; specialized agents create single points of failure |
| Not including "FIX issues found" in delegation prompts | Without explicit action directive, agents only report problems without making changes |
| Setting model to Haiku for content generation | Default to Sonnet; Haiku only for script execution, fast lookups, or pass/fail checks |
| Not writing clear descriptions for custom agents | Claude uses the description field to decide when to auto-delegate; vague descriptions prevent delegation |
| Using MCP tools in background subagents | MCP tools are not available in background subagents; run in foreground instead |
| Not preloading skills into subagents | Subagents do not inherit skills from the parent; list them explicitly in the skills field |