Agent skill
agent-builder
Creates Claude Code agent files (.claude/agents/*.md) with YAML frontmatter, tool permissions, and system prompts. Use when building new agents, configuring agent frontmatter, writing agent system prompts, or setting agent tool permissions.
Install this agent skill to your Project
npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/agent-builder-bsamiee-parametric-portal
SKILL.md
[H1][AGENT-BUILDER]
Dictum: Structured frontmatter and scoped tools enable discoverable agents.
Specialized execution contexts for Claude Code subagent delegation. Frontmatter controls discovery and capabilities; markdown body encodes behavior.
Location: .claude/agents/ (project) or ~/.claude/agents/ (user). Higher priority wins: CLI flag > project > user > plugin.
Tasks:
- Read index.md — Reference file listing for navigation.
- Read frontmatter.md — Complete schema (11 fields), triggers, syntax.
- Read prompt.md — Structure patterns, constraint markers.
- Read workflow.md — 5-phase creation process.
- (prose) Load
style-standardsskill — Voice, formatting, constraints. - Execute per workflow — UNDERSTAND, ACQUIRE, RESEARCH, AUTHOR, VALIDATE.
- Validate — Quality gate; see §VALIDATION.
Templates: →agent.template.md — Standard agent scaffold.
[REFERENCE]: index.md — Complete reference file listing.
[1][FRONTMATTER]
Dictum: Metadata enables discovery before load.
---
name: agent-name
description: >-
Capability statement. Use when scenario-1, scenario-2, or scenario-3.
tools: Read, Glob, Grep
model: sonnet
skills:
- style-standards
memory: user
---
| [INDEX] | [FIELD] | [TYPE] | [REQ] | [CONSTRAINT] |
|---|---|---|---|---|
| [1] | name |
string | Yes | Kebab-case, max 64 chars, match filename |
| [2] | description |
string | Yes | Third person, active voice, "Use when" clause |
| [3] | tools |
list | No | Comma-separated allowlist; omit = inherit all |
| [4] | disallowedTools |
list | No | Denylist; removed from inherited/allowed tools |
| [5] | model |
enum | No | haiku, sonnet, opus, inherit |
| [6] | permissionMode |
enum | No | default, acceptEdits, delegate, dontAsk, bypassPermissions, plan |
| [7] | maxTurns |
number | No | Maximum agentic turns before subagent stops |
| [8] | skills |
list | No | Full skill content preloaded at startup |
| [9] | mcpServers |
object | No | MCP servers available to this subagent |
| [10] | hooks |
object | No | Scoped lifecycle hooks (all 14 events supported) |
| [11] | memory |
enum | No | user, project, or local persistent scope |
[IMPORTANT] Agent background color set interactively via /agents UI — not frontmatter field.
[2][DISCOVERY]
Dictum: Description quality determines invocation accuracy.
Reasoning matches description directly — no embeddings, no keyword matching.
| [INDEX] | [PATTERN] | [EXAMPLE] | [MECHANISM] |
|---|---|---|---|
| [1] | "Use when" clause | Use when building MCP servers |
Direct activation signal |
| [2] | Proactive trigger | Use proactively after code changes |
Encourages auto-invocation |
| [3] | Imperative emphasis | MUST BE USED before committing |
Strong delegation signal |
| [4] | Enumerated list | (1) creating, (2) modifying |
Parallel pattern matching |
| [5] | Technology embed | Python (FastMCP) or TypeScript |
Framework-specific match |
[CRITICAL]:
- [NEVER] Hedging words:
might,could,should,probably. - [ALWAYS] Include "Use when" clause — 3+ trigger scenarios.
- [ALWAYS] Third person, active voice, present tense.
[3][TOOLS]
Dictum: Tool declarations scope permissions.
| [INDEX] | [PATTERN] | [TOOLS] | [USE_CASE] |
|---|---|---|---|
| [1] | Read-only | Read, Glob, Grep |
Analysis, review |
| [2] | Write-capable | Read, Edit, Write, Glob, Bash |
Implementation |
| [3] | Orchestration | Task(worker, researcher), Read |
Agent dispatch |
| [4] | Full access | (omit field) | Inherits all tools |
Task restriction: Task(agent_type) limits spawnable subagent types (main thread only).
Denylist: disallowedTools: Write, Edit removes tools from inherited or allowed set.
[4][MODELS]
Dictum: Model selection balances capability against latency and cost.
| [INDEX] | [MODEL] | [STRENGTH] | [LATENCY] | [COST] |
|---|---|---|---|---|
| [1] | opus | Complex reasoning | High | High |
| [2] | sonnet | Balanced performance | Medium | Medium |
| [3] | haiku | Fast, simple tasks | Low | Low |
| [4] | inherit | Match main conversation | Session | Session |
[5][SYSTEM_PROMPT]
Dictum: Structured prompts constrain execution.
Markdown body follows frontmatter. Body encodes agent behavior; structure determines effectiveness. Subagents receive only this system prompt (plus environment details), NOT full Claude Code system prompt.
[6][NAMING]
Dictum: Naming conventions enable discovery.
| [INDEX] | [PATTERN] | [EXAMPLE] | [USE_CASE] |
|---|---|---|---|
| [1] | Role-based | code-reviewer |
Specialized function |
| [2] | Action-based | generating-commits |
Gerund form preferred |
| [3] | Domain-specific | react-specialist |
Technology expertise |
[CRITICAL]:
- [NEVER] Generic names:
helper,processor,agent. - [ALWAYS] Kebab-case — lowercase, hyphens only. Filename matches
namefield.
[7][VALIDATION]
Dictum: Validation gates prevent incomplete artifacts.
[VERIFY] Completion:
- Workflow: All 5 phases executed (UNDERSTAND → VALIDATE).
- Frontmatter: Valid YAML, description with "Use when" clause.
- Tools: Matches type gate (readonly|write|orchestrator|full).
- Prompt: Role line + H2 sections + constraint markers.
- Quality: Kebab-case naming, filename matches
namefield.
[REFERENCE] Operational checklist: →validation.md.
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
majiayu000/claude-skill-registry
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
majiayu000/claude-skill-registry
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
majiayu000/claude-skill-registry
agent-ops-spec
Manage specification documents in .agent/specs/. Use when user provides requirements, acceptance criteria, or feature descriptions that need to be tracked and validated against implementation.
majiayu000/claude-skill-registry
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
majiayu000/claude-skill-registry
agent-ops-testing
Test strategy, execution, and coverage analysis. Use when designing tests, running test suites, or analyzing test results beyond baseline checks.
majiayu000/claude-skill-registry
agent-ops-state
Maintain .agent state files. Use at session start, after meaningful steps, and before concluding: read/update constitution/memory/focus/issues/baseline consistently.
Didn't find tool you were looking for?