@grantex/adapters

@grantex/adapters

Pre-built service provider adapters for Grantex — translate grant tokens into real API calls for Google Calendar, Gmail, Stripe, and Slack.

Install

npm install @grantex/adapters @grantex/sdk

Quick Start

import { GoogleCalendarAdapter } from '@grantex/adapters';

const calendar = new GoogleCalendarAdapter({
  jwksUri: 'https://your-auth-server/.well-known/jwks.json',
  credentials: process.env.GOOGLE_ACCESS_TOKEN!,
});

// Agent presents a grant token — adapter verifies it, checks scopes, calls Google API
const result = await calendar.listEvents(grantToken, {
  timeMin: new Date().toISOString(),
  maxResults: 10,
});

if (result.success) {
  console.log(result.data); // Google Calendar API response
}

Adapters

Google Calendar

Requires scopes: calendar:read, calendar:write

import { GoogleCalendarAdapter } from '@grantex/adapters';

const calendar = new GoogleCalendarAdapter({ jwksUri, credentials });

// List events (requires calendar:read)
await calendar.listEvents(token, { calendarId: 'primary', maxResults: 10 });

// Create event (requires calendar:write)
await calendar.createEvent(token, {
  summary: 'Team Sync',
  start: { dateTime: '2026-03-01T10:00:00Z' },
  end: { dateTime: '2026-03-01T11:00:00Z' },
});

Gmail

Requires scopes: email:read, email:send

import { GmailAdapter } from '@grantex/adapters';

const gmail = new GmailAdapter({ jwksUri, credentials });

// List messages (requires email:read)
await gmail.listMessages(token, { q: 'from:alice', maxResults: 5 });

// Send message (requires email:send)
await gmail.sendMessage(token, {
  to: '[e-mail]',
  subject: 'Hello',
  body: 'Hi Bob!',
});

Stripe

Requires scopes: payments:read, payments:initiate

Supports constraint enforcement — payments:initiate:max_500 limits payments to $500.

import { StripeAdapter } from '@grantex/adapters';

const stripe = new StripeAdapter({ jwksUri, credentials: process.env.STRIPE_SECRET_KEY! });

// List payment intents (requires payments:read)
await stripe.listPaymentIntents(token, { limit: 10 });

// Create payment intent (requires payments:initiate)
// If grant has payments:initiate:max_500, amount must be <= $500 (50000 cents)
await stripe.createPaymentIntent(token, {
  amount: 10000, // $100 in cents
  currency: 'usd',
});

Slack

Requires scopes: notifications:send, notifications:read

import { SlackAdapter } from '@grantex/adapters';

const slack = new SlackAdapter({ jwksUri, credentials: process.env.SLACK_BOT_TOKEN! });

// Send message (requires notifications:send)
await slack.sendMessage(token, { channel: 'C123ABC', text: 'Hello from agent!' });

// List messages (requires notifications:read)
await slack.listMessages(token, { channel: 'C123ABC', limit: 20 });

Configuration

interface AdapterConfig {
  jwksUri: string;             // JWKS endpoint for offline token verification
  credentials: CredentialProvider; // API key/token (string or async function)
  auditLogger?: AuditLogger;   // Optional audit logging callback
  clockTolerance?: number;     // JWT clock skew tolerance in seconds
  timeout?: number;            // Upstream request timeout in ms (default: 30000)
}

Dynamic Credentials

const calendar = new GoogleCalendarAdapter({
  jwksUri,
  credentials: async () => {
    // Fetch a fresh access token from your token store
    return await refreshGoogleToken(serviceAccountId);
  },
});

Audit Logging

import { Grantex } from '@grantex/sdk';

const grantex = new Grantex({ apiKey, baseUrl });

const stripe = new StripeAdapter({
  jwksUri,
  credentials: stripeKey,
  auditLogger: (params) => grantex.audit.log(params),
});

Constraint Enforcement

Scopes can include constraints like payments:initiate:max_500:

Constraint	Meaning	Example
max_N	Value must be <= N	payments:initiate:max_500 — max $500
min_N	Value must be >= N	payments:initiate:min_10 — min $10
limit_N	Count must be <= N	api:calls:limit_1000 — max 1000 calls

Error Handling

All adapters throw GrantexAdapterError with typed error codes:

Code	Meaning
TOKEN_INVALID	Grant token verification failed
SCOPE_MISSING	Grant doesn't include required scope
CONSTRAINT_VIOLATED	Value exceeds scope constraint
UPSTREAM_ERROR	Upstream API returned an error
CREDENTIAL_ERROR	Failed to resolve credentials

import { GrantexAdapterError } from '@grantex/adapters';

try {
  await stripe.createPaymentIntent(token, { amount: 100000, currency: 'usd' });
} catch (err) {
  if (err instanceof GrantexAdapterError) {
    console.error(err.code, err.message);
  }
}

Custom Adapters

Extend BaseAdapter to build your own:

import { BaseAdapter } from '@grantex/adapters';
import type { AdapterConfig, AdapterResult } from '@grantex/adapters';

class MyApiAdapter extends BaseAdapter {
  constructor(config: AdapterConfig) {
    super(config);
  }

  async getData(token: string): Promise<AdapterResult> {
    const { grant } = await this.verifyAndCheckScope(token, 'myapi:read');
    const credential = await this.resolveCredential();

    const data = await this.callUpstream('https://api.myservice.com/data', {
      method: 'GET',
      headers: { Authorization: `Bearer ${credential}` },
    });

    await this.logAudit(grant, 'myapi:getData', 'success');
    return this.wrapResult(grant, data);
  }
}

Requirements

• Node.js 18+
• @grantex/sdk >= 0.1.0

License

Apache-2.0