Callstack Agent Skills is a collection of instructions that gives AI coding assistants practical knowledge for building React Native applications. Developers use it for app development, performance, navigation, testing, CI, device automation, and migrations to React Native. The catalogue entries are the project's skills, rules, and instructions for compatible coding assistants.
Borrowing it
Nothing to install: this file belongs to callstackincubator/agent-skills. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/callstackincubator/agent-skills/main/AGENTS.mdgit clone --depth 1 https://github.com/callstackincubator/agent-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/callstackincubator/agent-skills/agents-md)<a href="https://agentmods.dev/instructions/callstackincubator/agent-skills/agents-md"><img src="https://agentmods.dev/badge/instructions/callstackincubator/agent-skills/agents-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/callstackincubator/agent-skills/agents-md"><img src="https://agentmods.dev/badge/instructions/callstackincubator/agent-skills/agents-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00709 | $0.00709 |
| Opus 5.5 | $0.00284 | $0.00284 |
| Sonnet 5.5 | $0.00142 | $0.00142 |
| Haiku 4.5 | $0.00071 | $0.00071 |
Grade A, and why
agent-skills AGENTS.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Skills
Markdown-only repo with agent skills for React Native and GitHub workflows. No build step.
Adding New Skills
Follow agentskills.io spec and Claude Code best practices.
Quick Checklist
- Create
skills/<skill-name>/SKILL.md - Directory name must match
namefield exactly - Required frontmatter:
--- name: skill-name # lowercase, hyphens only, 1-64 chars description: Third person description of what it does. Use when [trigger conditions]. --- - Optional frontmatter:
license,metadata(author, tags),compatibility - Keep body under 500 lines
- Use markdown links:
[file.md](references/file.md)not bare filenames - Run
/validate-skillsto verify
What Makes a Good Skill
- Concise: Only add context Claude doesn't already have
- Third person description: "Processes X" not "I help with X"
- What + When: Description says what it does AND when to use it
- One-level deep: Reference files link from SKILL.md, not from other references
- No redundancy: Don't repeat description content in body
Repo Structure
skills/
├── react-native-best-practices/
│ ├── SKILL.md # Main entry point with quick reference + problem→skill mapping
│ └── references/
│ ├── images/ # Visual references (profiler screenshots, diagrams)
│ ├── js-*.md # JavaScript/React skills
│ ├── native-*.md # iOS/Android native skills
│ └── bundle-*.md # Bundling & app size skills
│
└── react-native-tv-best-practices/
├── SKILL.md # Main entry point with priority framework + problem→reference routing
└── references/
├── focus-*.md # Focus / D-pad navigation
├── nav-*.md # Directional navigation & keyboard
├── design-*.md # 10-foot design (typography, layout, color)
├── perf-*.md # TV performance (lists, memory, animations)
├── video-*.md # Video streaming, players, DRM
├── a11y-*.md # TV accessibility
├── setup-*.md # Cross-platform setup & architecture
├── test-*.md # Testing strategy
└── release-*.md # CI/CD
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 72 lines · 709 tokens per session scan A 8995509d82f1
agent-skills AGENTS.md is an instructions file published in the GitHub repository callstackincubator/agent-skills (1,702 stars, last pushed 29d ago), licensed MIT. It adds 709 tokens to every session, about $0.0028 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
agent-skills AGENTS.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| agent-skills AGENTS.mdcallstackincubator/agent-skills | Instructions file | 1.7k | 29d ago | MIT | A | 709 | Codex, OpenCode |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | today | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |