name: skillify
description: Generates SKILL.md files for npm packages following Anthropic's Agent Skills specification. Use when adding agent documentation to an npm package, making a package AI-agent friendly, or creating skills from existing code.

Skillify

Generate a SKILL.md file for an npm package, making it discoverable and usable by AI agents.

When to Use

• Adding agent documentation to an npm package
• Making a library AI-agent friendly
• Creating a skill from existing CLI tool
• Preparing a package for the Agent Skills ecosystem

Quick Start

/skillify .                    # Current directory
/skillify ~/path/to/package    # Local package
/skillify btctx                # npm package name

Process

Step 1: Gather Package Information

Read these files (in order of importance):

1. package.json (required)
2. name → skill name (kebab-case)
3. description → base for skill description
4. bin → CLI commands available
5. main/exports → API entry points

6. keywords → trigger words

7. README.md (if exists)

8. Usage examples
9. API documentation

10. Installation instructions

11. CLI entry point (if bin exists)

12. Parse for --help output

13. Extract flags and commands

14. Main module (if main/exports exists)

15. Exported functions
16. JSDoc comments
17. Type definitions

Step 2: Analyze for Agent Usage

Determine:
- What it does - core functionality in one sentence
- When to use - specific triggers/contexts
- How to use - primary usage pattern (CLI or API)
- Examples - concrete input/output pairs

Step 3: Generate SKILL.md

Follow this template:

---
name: <package-name-kebab-case>
description: <What it does>. <When to use - specific triggers>.
---

Description rules:
- Third person only ("Builds X" not "I build X")
- Under 1024 characters
- Include both WHAT and WHEN
- Use specific keywords for discovery

Body structure:

# <Package Name>

## When to Use

Invoke when you need to:
- <specific trigger 1>
- <specific trigger 2>
- <specific trigger 3>

## Quick Start

<primary usage pattern - CLI or code>

## Examples

**Example 1: <use case>**

Input:
<concrete input>

Output:
<concrete output>

## CLI Reference (if applicable)

<flags and commands>

## API Reference (if applicable)

<key exported functions>

Step 4: Write the File

Save to: <package-root>/SKILL.md

Quality Checklist

Before finalizing, verify:

• [ ] Description is third person
• [ ] Description includes WHAT and WHEN
• [ ] Description under 1024 characters
• [ ] Name is kebab-case, lowercase
• [ ] Examples are concrete (not abstract)
• [ ] Body under 500 lines
• [ ] No time-sensitive information
• [ ] Consistent terminology

Description Formula

<Verb>s <object> [details]. Use when <trigger1>, <trigger2>, or <trigger3>.

Good examples:

description: Builds Bitcoin Taproot transactions from inputs and outputs. Use when creating P2TR transactions, spending UTXOs, or working with Taproot addresses.

description: Broadcasts signed Bitcoin transactions to the network. Use when sending transactions to mempool, publishing to testnet4, or checking broadcast status.

Bad examples:

description: Helps with Bitcoin stuff.  # Too vague
description: I can build transactions.  # Wrong POV
description: A library for transactions.  # No "when to use"

Naming Convention

Convert package name to kebab-case:

Example Output

For a package like btctx:

---
name: btctx
description: Builds Bitcoin Taproot (P2TR) transactions from UTXOs. Use when creating Bitcoin transactions, spending Taproot outputs, or building raw transaction hex.
---

# btctx

## When to Use

Invoke when you need to:
- Build a Bitcoin transaction from UTXOs
- Create Taproot (P2TR) outputs
- Generate signed transaction hex for broadcasting

## Quick Start

```javascript
import { buildTx } from 'btctx';

const { hex, txid } = await buildTx({
  privateKey: '...',
  publicKey: '...',
  txid: '<input-txid>',
  vout: 0,
  inputAmount: 100000,
  outputs: [{ pubkey: '<recipient>', amount: 99000 }]
});

Examples

Example: Simple transfer

Input:
- 100,000 sats from UTXO
- Send to one recipient

Output:
- Signed transaction hex
- Transaction ID (txid)

API Reference

buildTx(options)

Builds and signs a Taproot transaction.

Options:
- privateKey - 64-char hex signing key
- publicKey - 64-char hex x-only pubkey
- txid - Input transaction ID
- vout - Output index to spend
- inputAmount - Satoshis in input
- outputs - Array of { pubkey, amount }

Returns: { hex, txid }
```

References

• Agent Skills Specification
• Anthropic Best Practices
• GitHub: anthropics/skills