Agent skill · product strategy · sundial-org
agent-development
Design and build custom Claude Code agents with effective descriptions, tool access patterns, and self-documenting prompts. Covers Task tool delegation, model selection, memory limits, and declarative instruction design. Use when: creating custom agents, designing agent descriptions for auto-delegation, troubleshooting agent memory issues, or building agent pipelines.
Why this skill is useful
Provides specific patterns and configurations for building custom agents that the AI wouldn't reliably generate on its own.
What it needs
About 6k tokens when loaded. Last updated 2026-03-07. 639 stars on the source repository.
What this skill does
Agent Development for Claude Code Build effective custom agents for Claude Code with proper delegation, tool access, and prompt design. Agent Description Pattern The description field determines whether Claude will automatically delegate tasks. Strong Trigger Pattern Weak vs Strong Descriptions Weak (won't auto-delegate) Strong (auto-delegates) --------------------------- ------------------------- "Analyzes screenshots for issues" "Visual QA specialist. MUST BE USED when analyzing screenshots. Use PROACTIVELY for visual QA." "Runs Playwright scripts" "Playwright specialist. MUST BE USED when running Playwright scripts. Use PROACTIVELY for browser automation." Key phrases: "MUST BE USED when..." "Use PROACTIVELY for..." Include trigger keywords Delegation Mechanisms 1. Explicit: Task tool subagenttype: "agent-name" - always works 2. Automatic: Claude matches task to agent description - requires strong phrasing Session restart required after creating/modifying agents. Tool Access Principle If an agent doesn't need Bash, don't give it Bash. Agent needs to... Give tools Don't give ------------------- ------------ ------------ Create files only Read, Write, Edit, Glob, Grep Bash Run scripts/CLIs Read, Write, Edit, Glob, Grep, Bash — Read/audit only Read, Glob, Grep Write, Edit, Bash Why? Models default to cat > file << 'EOF' heredocs instead of Write tool. Each bash command requires approval, causing dozens of prompts per agent run. Allowlist Pattern Instead of restricting Bash, allowlist safe commands in .claude/settings.json: Model Selection (Quality First) Don't downgrade quality to work around issues - fix root causes instead. Model Use For ------- --------- Opus Creative work (page building, design, content) - quality matters Sonnet Most agents - content, code, research (default) Haiku Only script runners where quality doesn't matter Memory Limits Root Cause Fix (REQUIRED) Add to ~/.bashrc or ~/.zshrc: Increases Node.js heap from 4GB to 16GB. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills sundial-org/agent-development