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Preview Feature — This feature is currently in preview and under active development. APIs and functionality may change. We recommend testing thoroughly before using in production.

Agent Tools

Tools are functions that agents can invoke to interact with external systems, retrieve data, or perform actions. This guide covers how to create, configure, and manage tools.

Tool Anatomy​

Every tool has these components:

{
  tag: 'tool-identifier',           // Unique identifier
  name: 'Human Readable Name',      // Optional display name
  description: 'What this tool does', // LLM uses this to decide when to call
  parameters: {                     // Input schema
    param1: {
      type: 'string',
      description: 'Parameter description',
      required: true,
    },
  },
  handler: async (ctx, params) => { // Implementation
    return result;
  },
  requiresConfirmation: false,      // Needs human approval?
  timeout: 30000,                   // Timeout in ms
  retries: 2,                       // Retry on failure
  costEstimate: 0.01,               // Estimated cost per call
}

Parameter Types​

String​

parameters: {
  name: {
    type: 'string',
    description: 'User name',
    required: true,
  },
  email: {
    type: 'string',
    description: 'Email address',
    required: true,
  },
}

Number​

parameters: {
  amount: {
    type: 'number',
    description: 'Amount in dollars',
    required: true,
  },
  quantity: {
    type: 'number',
    description: 'Number of items',
    default: 1,
  },
}

Boolean​

parameters: {
  includeArchived: {
    type: 'boolean',
    description: 'Include archived items in results',
    default: false,
  },
}

Enum (Constrained Values)​

parameters: {
  status: {
    type: 'string',
    description: 'Order status',
    enum: ['pending', 'processing', 'shipped', 'delivered'],
    required: true,
  },
  priority: {
    type: 'string',
    description: 'Priority level',
    enum: ['low', 'medium', 'high', 'urgent'],
    default: 'medium',
  },
}

Array​

parameters: {
  tags: {
    type: 'array',
    description: 'List of tags to apply',
    items: { type: 'string' },
  },
  productIds: {
    type: 'array',
    description: 'List of product IDs',
    items: { type: 'number' },
    required: true,
  },
}

Object​

parameters: {
  address: {
    type: 'object',
    description: 'Shipping address',
    properties: {
      street: { type: 'string', description: 'Street address' },
      city: { type: 'string', description: 'City' },
      state: { type: 'string', description: 'State/Province' },
      zip: { type: 'string', description: 'ZIP/Postal code' },
      country: { type: 'string', description: 'Country' },
    },
    required: true,
  },
}

Tool Handler Context​

The handler receives a context object with access to Ductape resources:

handler: async (ctx, params) => {
  // Execution metadata
  ctx.executionId;    // Unique execution ID
  ctx.agentTag;       // Agent tag
  ctx.env;            // Environment (dev, staging, prd)
  ctx.product;        // Product tag
  ctx.iteration;      // Current iteration number
  ctx.sessionId;      // Session ID for memory

  // Input data
  ctx.input;          // Original user input

  // History
  ctx.conversationHistory;  // Message history
  ctx.toolCallHistory;      // Previous tool calls

  // Custom state
  ctx.state;          // Agent state object
  ctx.setState(key, value);
  ctx.getState(key);

  // Ductape resources (see below)
  ctx.action;
  ctx.database;
  ctx.graph;
  ctx.storage;
  ctx.notification;
  ctx.publish;
  ctx.feature;

  // Memory operations
  ctx.remember(data);  // Store in vector memory
  ctx.recall(query);   // Query vector memory
}

Accessing Ductape Resources​

Actions (External APIs)​

handler: async (ctx, params) => {
  const response = await ctx.action.run({
    app: 'stripe',
    event: 'create-charge',
    input: {
      amount: params.amount * 100,
      currency: 'usd',
      customer: params.customerId
    },
    retries: 3,
    timeout: 10000,
  });

  return { chargeId: response.id, status: response.status };
}

The input uses flat format - fields are automatically resolved to body, params, query, or headers based on the action's schema. For explicit placement, use prefixes like 'headers:X-Custom': 'value'.

Databases​

handler: async (ctx, params) => {
  // Query
  const users = await ctx.database.query({
    database: 'users-db',
    event: 'find-users',
    params: { status: 'active' },
  });

  // Insert
  const newUser = await ctx.database.insert({
    database: 'users-db',
    event: 'create-user',
    data: { email: params.email, name: params.name },
  });

  // Update
  await ctx.database.update({
    database: 'users-db',
    event: 'update-user',
    where: { id: params.userId },
    data: { status: 'verified' },
  });

  // Delete
  await ctx.database.delete({
    database: 'users-db',
    event: 'delete-user',
    where: { id: params.userId },
  });

  return { success: true };
}

Graph Databases​

handler: async (ctx, params) => {
  // Create node
  const node = await ctx.graph.createNode({
    graph: 'social-graph',
    labels: ['User'],
    properties: { name: params.name },
  });

  // Create relationship
  await ctx.graph.createRelationship({
    graph: 'social-graph',
    from: node.id,
    to: params.friendId,
    type: 'FRIENDS_WITH',
  });

  // Query
  const friends = await ctx.graph.query({
    graph: 'social-graph',
    action: 'find-friends',
    params: { userId: params.userId },
  });

  return { friends };
}

Storage​

handler: async (ctx, params) => {
  // Upload
  const file = await ctx.storage.upload({
    storage: 'documents',
    event: 'upload-file',
    input: {
      buffer: params.fileData,
      fileName: params.fileName,
      mimeType: params.mimeType,
    },
  });

  // Download
  const download = await ctx.storage.download({
    storage: 'documents',
    event: 'get-file',
    input: { file_key: params.fileKey },
  });

  // Delete
  await ctx.storage.delete({
    storage: 'documents',
    event: 'remove-file',
    input: { file_key: params.fileKey },
  });

  return { url: file.url };
}

Notifications​

handler: async (ctx, params) => {
  // Email
  await ctx.notification.email({
    notification: 'transactional',
    event: 'order-confirmation',
    recipients: [params.email],
    subject: { orderId: params.orderId },
    template: { orderId: params.orderId, items: params.items },
  });

  // SMS
  await ctx.notification.sms({
    notification: 'alerts',
    event: 'shipping-update',
    phones: [params.phone],
    message: { trackingNumber: params.tracking },
  });

  // Push
  await ctx.notification.push({
    notification: 'mobile',
    event: 'new-message',
    tokens: [params.deviceToken],
    title: { sender: params.senderName },
    body: { preview: params.messagePreview },
  });

  return { sent: true };
}

Message Publishing​

handler: async (ctx, params) => {
  await ctx.publish.send({
    broker: 'order-events',
    event: 'order-created',
    input: {
      message: {
        orderId: params.orderId,
        customerId: params.customerId,
        items: params.items,
      },
    },
    retries: 3,
  });

  return { published: true };
}

Features (Workflows)​

handler: async (ctx, params) => {
  const result = await ctx.feature.run({
    feature: 'process-order',
    input: {
      orderId: params.orderId,
      action: 'fulfill',
    },
  });

  return result;
}

Vector Memory Operations​

Remember (Store)​

handler: async (ctx, params) => {
  await ctx.remember({
    content: params.information,
    metadata: {
      type: 'user_preference',
      userId: ctx.sessionId,
      category: params.category,
      timestamp: new Date().toISOString(),
    },
  });

  return { stored: true };
}

Recall (Query)​

handler: async (ctx, params) => {
  const memories = await ctx.recall({
    query: params.query,
    topK: 5,
    filter: {
      userId: ctx.sessionId,
      type: 'user_preference',
    },
    minScore: 0.7,
  });

  return {
    found: memories.matches.length,
    results: memories.matches.map((m) => m.metadata),
  };
}

Portable Tools with handlerRef​

For tools that should work when loaded from the database, use handlerRef instead of inline handlers:

tools: [
  {
    tag: 'process-payment',
    description: 'Process a payment',
    parameters: {
      amount: { type: 'number', required: true },
      customerId: { type: 'string', required: true },
    },
    handlerRef: 'action:stripe:create-charge',
  },
  {
    tag: 'get-customer',
    description: 'Look up customer information',
    parameters: {
      customerId: { type: 'string', required: true },
    },
    handlerRef: 'database:customers-db:find-customer',
  },
  {
    tag: 'run-checkout',
    description: 'Run checkout workflow',
    parameters: {
      cartId: { type: 'string', required: true },
    },
    handlerRef: 'feature:checkout-flow',
  },
]

handlerRef Format​

type:tag:event

TypeFormatDescription
actionaction:app-tag:eventCall an app action
databasedatabase:db-tag:eventDatabase query
graphgraph:graph-tag:actionGraph operation
storagestorage:storage-tag:eventStorage operation
notificationnotification:notif-tag:eventSend notification
publishpublish:broker-tag:eventPublish message
featurefeature:feature-tagRun feature

Tool Options​

Timeout​

Set maximum execution time:

{
  tag: 'slow-operation',
  description: 'A slow operation',
  timeout: 60000,  // 60 seconds
  handler: async (ctx, params) => {
    // Long-running operation
  },
}

Retries​

Automatically retry on failure:

{
  tag: 'unreliable-api',
  description: 'Call an unreliable API',
  retries: 3,  // Retry up to 3 times
  handler: async (ctx, params) => {
    // May fail occasionally
  },
}

Human Approval​

Require confirmation before execution:

{
  tag: 'delete-account',
  description: 'Permanently delete a user account',
  requiresConfirmation: true,
  handler: async (ctx, params) => {
    // Destructive operation
  },
}

Cost Estimation​

Track estimated costs:

{
  tag: 'expensive-operation',
  description: 'An operation that costs money',
  costEstimate: 0.10,  // $0.10 per call
  handler: async (ctx, params) => {
    // Paid API call
  },
}

Best Practices​

1. Write Clear Descriptions​

The LLM uses descriptions to decide when to use tools:

// Good - specific and actionable
description: 'Search for products by name, category, or price range. Returns matching products with prices and availability.'

// Bad - vague
description: 'Search products'

2. Use Descriptive Parameter Names​

// Good
parameters: {
  customerEmail: { type: 'string', description: 'Customer email address' },
  orderDateFrom: { type: 'string', description: 'Start date for order search (YYYY-MM-DD)' },
}

// Bad
parameters: {
  e: { type: 'string' },
  d: { type: 'string' },
}

3. Return Structured Data​

// Good - structured, informative
handler: async (ctx, params) => {
  const order = await getOrder(params.orderId);
  return {
    found: true,
    order: {
      id: order.id,
      status: order.status,
      total: order.total,
      items: order.items.length,
    },
  };
}

// Bad - unstructured
handler: async (ctx, params) => {
  return await getOrder(params.orderId);
}

4. Handle Errors Gracefully​

handler: async (ctx, params) => {
  try {
    const result = await riskyOperation(params);
    return { success: true, data: result };
  } catch (error) {
    return {
      success: false,
      error: error.message,
      suggestion: 'Try with different parameters',
    };
  }
}

5. Validate Inputs​

handler: async (ctx, params) => {
  // Validate email format
  if (!isValidEmail(params.email)) {
    return { error: 'Invalid email format' };
  }

  // Validate amount
  if (params.amount <= 0) {
    return { error: 'Amount must be positive' };
  }

  // Proceed with operation
  return await processPayment(params);
}

Next Steps​