Create Agent
vectorize-io/hindsight
Create a new Hindsight-powered subagent with long-term memory.
Expert at creating and modifying Claude Code agents (subagents).
Install Building Agents
$ npx skills add aiskillstore/marketplace --skill building-agents -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install aiskillstore/marketplace building-agents --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/c0ntr0lledcha0s/building-agents .claude/skills/building-agents && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "building-agents" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agents into .claude/skills/building-agents/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "building-agents", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agentsType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add aiskillstore/marketplace --skill building-agents -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install aiskillstore/marketplace building-agents --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/c0ntr0lledcha0s/building-agents .agents/skills/building-agents && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "building-agents" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agents into .agents/skills/building-agents/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "building-agents", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add aiskillstore/marketplace --skill building-agents -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install aiskillstore/marketplace building-agents --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/c0ntr0lledcha0s/building-agents .cursor/skills/building-agents && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "building-agents" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agents into .cursor/skills/building-agents/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "building-agents", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/aiskillstore/marketplace.git --path skills/c0ntr0lledcha0s/building-agents--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add aiskillstore/marketplace --skill building-agents -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install aiskillstore/marketplace building-agents --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/c0ntr0lledcha0s/building-agents .gemini/skills/building-agents && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "building-agents" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agents into .gemini/skills/building-agents/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "building-agents", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install aiskillstore/marketplace building-agentsInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add aiskillstore/marketplace --skill building-agents -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/c0ntr0lledcha0s/building-agents .github/skills/building-agents && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "building-agents" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agents into .github/skills/building-agents/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "building-agents", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add aiskillstore/marketplace --skill building-agents -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install aiskillstore/marketplace building-agents --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/aiskillstore/marketplace.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/c0ntr0lledcha0s/building-agents .opencode/skills/building-agents && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "building-agents" agent skill from https://github.com/aiskillstore/marketplace/tree/main/skills/c0ntr0lledcha0s/building-agents into .opencode/skills/building-agents/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "building-agents", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
building-agents- GitHub stars
- 430
- Token cost
- ~4.2k tokens
- SKILL.md length
- 1,467 words
- Files
- 9 (incl. scripts, references)
- Skills in repo
- 1,044
- Repo updated
- First seen
- Licence
- None found
At a glance
Expert at creating and modifying Claude Code agents (subagents).
- Works in 5 steps: Gather Requirements → Design the Agent → Write the Agent File → …
- Wants to create
- SKILL.md covers When to Create an Agent vs…, Agent Schema & Structure, Subagent Architecture… and Agent Body Content, plus 5 more sections
- Runs Python scripts from its folder; calls python3 and git
What it does
Building Agents is an agent skill from aiskillstore/marketplace. Expert at creating and modifying Claude Code agents (subagents). Auto-invokes when the user wants to create, update, modify, enhance, validate, or standardize agents, or when modifying agent YAML frontmatter fields (especially 'model', 'tools', 'description'), needs help designing agent architecture, or wants to understand agent capabilities. Also auto-invokes proactively when Claude is about to write agent files (/agents/.md), create modular agent architectures, or implement tasks that involve creating agent…
Its SKILL.md is about 4.2k tokens, which your agent loads only when the skill is triggered. The skill folder holds 11 other files, including scripts and reference files (for example `references/agent-examples.md`, `references/agent-update-patterns.md` and `references/color-palette.md`).
It sits in Agent Workflows, covering Building AI agents and Subagents. The repository describes itself as: Security-audited skills for Claude, Codex & Claude Code. One-click install, quality verified.
When your agent uses it
- Wants to create
- Standardize agents
- Modifying agent YAML frontmatter fields (especially model
- Needs help designing agent architecture
Example prompts
- “description”
- “/building-agents”
Requirements
- Python 3
- Pre-approved tools (allowed-tools): Read, Write, Edit, Grep, Glob, Bash
Workflow steps
5 steps, taken from the step headings in SKILL.md.
- Gather Requirements
- Design the Agent
- Write the Agent File
- Validate the Agent
- Test the Agent
What it can do on your machine
Read from SKILL.md and the folder at commit 755bc35. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves these tools, so the agent can use them without asking each time:
ReadWriteEditGrepGlobBash
From allowed-tools in the SKILL.md frontmatter.
Runs code
Ships 1 file in scripts/ (Python), which the agent can run.
Shell commands in SKILL.md call:
python3git
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use git, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Building Agents loads about 4.2k tokens when it runs, and up to ~15k if it reads all its reference files. Until then it costs about 136 tokens; SKILL.md has 1,467 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check: notes
The automated check noted patterns worth knowing about, such as sudo or a known installer.
- NotePre-approves every shell command (allowed-tools: Bash)SKILL.md
allowed-tools: Read, Write, Edit, Grep, Glob, Bash
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); the scripts in this folder are not scanned.
SKILL.md
Without a licence we can't republish the file, so here is its outline and opening line. It has 1,467 words (~4,157 tokens).
“You are an expert at creating Claude Code agents (subagents). Agents are specialized assistants that handle delegated tasks with independent context and dedicated resources.”
- name
- building-agents
- allowed-tools
- Read, Write, Edit, Grep, Glob, Bash
- version
- 2.0.0
Files
SKILL.md and 8 other files (scripts, references) in skills/c0ntr0lledcha0s/building-agents of aiskillstore/marketplace.
- SKILL.md
- references/agent-examples.md
- references/agent-update-patterns.md
- references/color-palette.md
- references/migration-guide.md
- scripts/validate-agent.py
- skill-report.json
- templates/agent-checklist.md
- templates/agent-template.md
Open the folder on GitHubat commit 755bc35
Compare with similar skills
Building Agents next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Building Agents this skillaiskillstore/marketplace | 430 | — | ~4.2k | Automated safety check: Notes | None | |
| Create Agentvectorize-io/hindsight | 47k | — | ~1.1k | Automated safety check: Pass | MIT | |
| Deep Agentslangchain-ai/docs | 426 | — | ~1.1k | Automated safety check: Pass | MIT | |
| Create AgentApocrathia/home-assistant-config | 179 | — | ~1.1k | Automated safety check: Pass | None | |
| Agent Creatorsickn33/agentic-awesome-skills | 47k | 1 repos | ~2.7k | Automated safety check: Pass | MIT | |
| Agent Creatorjeremylongshore/tons-of-skills-marketplace | 2.8k | — | ~4k | Automated safety check: Pass | MIT |
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Related
Categories
Questions about Building Agents
What does Building Agents do?
Expert at creating and modifying Claude Code agents (subagents). Building Agents is an agent skill from aiskillstore/marketplace. Expert at creating and modifying Claude Code agents (subagents).
When should I use Building Agents?
Building Agents fits situations like: wants to create; standardize agents; modifying agent YAML frontmatter fields (especially model; needs help designing agent architecture.
How do I install Building Agents in Claude Code?
Run `npx skills add aiskillstore/marketplace --skill building-agents -a claude-code`. Or copy the skill folder (skills/c0ntr0lledcha0s/building-agents in aiskillstore/marketplace) into .claude/skills/building-agents in your project. Claude Code loads it when a task matches its description.
How do I install Building Agents in Codex?
Run `npx skills add aiskillstore/marketplace --skill building-agents -a codex`. Or copy the skill folder (skills/c0ntr0lledcha0s/building-agents in aiskillstore/marketplace) into .agents/skills/building-agents in your project. Codex loads it when a task matches its description.
Can I use Building Agents in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add aiskillstore/marketplace --skill building-agents -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/building-agents, .gemini/skills/building-agents, .github/skills/building-agents and .opencode/skills/building-agents in your project.
What does Building Agents need to run?
Going by SKILL.md and its folder, Building Agents needs Python for the scripts in its folder and the command-line tools its instructions call (python3 and git). Our summary lists: Python 3. Its frontmatter pre-approves these tools: Read, Write, Edit, Grep, Glob, Bash.
Does Building Agents access the network?
SKILL.md contains no URLs. Its commands use git, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Building Agents safe to install?
Our automated static check of SKILL.md found notes only (pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. The check reads SKILL.md only: the scripts in the folder are not scanned, so read them before running anything.
What licence does Building Agents use?
No licence was found for Building Agents or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.
How many tokens does Building Agents use?
About 4.2k tokens (SKILL.md is roughly 17k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 11k tokens, read only when the agent opens those files.
What are the alternatives to Building Agents?
Skills that share tags, products or a category with Building Agents: Create Agent (vectorize-io/hindsight, 47k stars), Deep Agents (langchain-ai/docs, 426 stars), Create Agent (Apocrathia/home-assistant-config, 179 stars) and Agent Creator (sickn33/agentic-awesome-skills, 47k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Building Agents?
aiskillstore (a GitHub organization) maintains it in aiskillstore/marketplace, which has 430 GitHub stars. The repository holds 1,044 skills in this directory. The repository was last updated on October 9, 2026.
Source: aiskillstore/marketplace on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.