# Skills
Skills are reusable operations that combine multiple adapter calls.
## Using defineSkill
```typescript
import { defineSkill } from '@papicandela/mcx-core';
export const dailySummary = defineSkill({
name: 'daily-summary',
description: 'Summarize daily activity across systems',
adapters: ['crm', 'analytics'],
code: `
const leads = await crm.getLeads({ date: inputs.date });
const visits = await analytics.getPageViews({ date: inputs.date });
return {
date: inputs.date,
leads: leads.length,
visits: sum(visits, 'count'),
conversion: (leads.length / sum(visits, 'count') * 100).toFixed(2) + '%'
};
`,
sandbox: {
timeout: 10000,
memoryLimit: 128,
},
});
```
## Using skillBuilder (Fluent API)
```typescript
import { skillBuilder } from '@papicandela/mcx-core';
export const processData = skillBuilder('process-data')
.description('Fetch, transform, and store data')
.requires('api', 'db')
.timeout(15000)
.memoryLimit(256)
.code(`
const raw = await api.fetchRecords({ limit: 1000 });
const filtered = pick(raw, ['id', 'name', 'amount']);
const result = await db.bulkInsert(filtered);
return { inserted: result.count };
`)
.build();
```
## Native Function Skills
For complex logic, use a native TypeScript function instead of code string:
```typescript
export const complexSkill = defineSkill({
name: 'complex-operation',
description: 'Skill with native TypeScript logic',
adapters: ['api'],
run: async ({ adapters, inputs }) => {
const data = await adapters.api.getData(inputs);
// Complex processing with full TypeScript support
const processed = data
.filter(item => item.active)
.map(item => ({
...item,
score: calculateScore(item),
}))
.sort((a, b) => b.score - a.score);
return { top10: processed.slice(0, 10) };
},
});
```
## Directory Structure
Skills can be single files or directories:
```
skills/
├── daily-summary.ts # Single file skill
├── complex-workflow/ # Directory skill
│ ├── index.ts # Entry point (required)
│ └── helpers.ts # Supporting modules
```
## Running Skills
```bash
# Run via CLI
mcx run daily-summary date=2024-01-15
# Via MCP tool
mcx_run_skill({ name: "daily-summary", inputs: { date: "2024-01-15" } })
```
