Elite Voice Agents

Tag: API

  • Tools Tutorial – Step by Step – Vapi – Functions, DTMF, End Call, Transfers, API

    Tools Tutorial – Step by Step – Vapi – Functions, DTMF, End Call, Transfers, API

    Master Vapi tools with this step-by-step walkthrough titled Tools Tutorial – Step by Step – Vapi – Functions, DTMF, End Call, Transfers, API. The video by Henryk Brzozowski shows how to use nearly every tool and how to get them to work together effectively.

    You’ll progress through Functions, Make Scenario, Attaching Tools, Tools Format/Response, End Call, Transfer Call, Send SMS, API Request, DTMF, Google Calendar, plus Twilio flows and an n8n response setup. Timestamps and resource notes help you reproduce the examples and leave feedback if something needs fixing.

    Prerequisites

    Before you begin building voice AI scenarios with Vapi, make sure you cover a few prerequisites so your setup and testing go smoothly. This section outlines account needs, credentials, supported platforms and the baseline technical knowledge you should have. If you skip these steps you may run into avoidable friction when wiring tools together or testing call flows.

    Account requirements for Vapi, Twilio, Google Calendar, and n8n

    You should create accounts for each service you plan to use: a Vapi account to author scenarios and host tools, a Twilio account for telephony and phone numbers, a Google account with Google Calendar API access if you need calendar operations, and an n8n account or instance if you prefer to run automation flows there. For Twilio, verify your phone number and, if you start with a trial account, be aware of restrictions like verified destination numbers and credits. For Google Calendar, create a project in the Google Cloud Console, enable the Calendar API, and create OAuth or service account credentials as required. For n8n, decide whether you’ll use a hosted instance or self-host; either way, ensure you have access and necessary permissions to add credentials and set webhooks.

    Required API keys and credentials and where to store them securely

    You will need API keys and secrets for Vapi, Twilio (Account SID, Auth Token), Google (OAuth client ID/secret or service account key), and potentially other APIs such as a Time API. Store these credentials securely in environment variables, a secrets manager, or a credential vault built into your deployment platform. Avoid embedding keys in source control or public places. For local development, use a .env file kept out of version control and use a tool like direnv or your runtime’s secret management. For production, prefer managed secret storage (cloud secret manager, HashiCorp Vault, or similar) and restrict access by role.

    Supported platforms and browsers for the tools tutorial

    Most Vapi tooling and dashboards are accessible via modern browsers; you should use the latest stable versions of Chrome, Firefox, Edge, or Safari for the best experience. Local development examples typically run on Node.js or Python runtimes on Windows, macOS, or Linux. If you follow the n8n instructions, n8n supports containerized or native installs and is compatible with those OS platforms. For tunnel testing (ngrok or alternatives), ensure you choose a client that runs on your OS and matches your security policies.

    Basic knowledge expected: HTTP, JSON, webhooks, and voice call flow concepts

    You should be comfortable reading and making HTTP requests, inspecting and manipulating JSON payloads, and understanding the concept of webhooks (HTTP callbacks triggered by events). Familiarity with voice call flows — prompts, DTMF tones, transfers, playbacks, and call lifecycle events — will help you design scenarios that behave correctly. If you know basic asynchronous programming patterns (promises, callbacks, or async/await) and how to parse logs, your troubleshooting will be much faster.

    Environment Setup

    This section walks through installing Vapi tools or accessing the dashboard, preparing local dev environments, verifying Twilio numbers, exposing local webhooks, and getting n8n ready if you plan to use it. The goal is to get you to a point where you can test real inbound and outbound call behavior.

    Installing and configuring Vapi tools package or accessing the Vapi dashboard

    If you have a Vapi CLI or tools package, install it per the platform instructions for your runtime (npm for Node, pip for Python, etc.). After installation, authenticate using API keys stored in environment variables or your system’s credential store. If you prefer the dashboard, log in to the Vapi web console and verify your workspace and organization settings. Configure any default tool directories or prompt vault access and confirm your account has permissions to create scenarios and add functions.

    Setting up local development environment: Node, Python, or preferred runtime

    Choose the runtime you are comfortable with. For Node.js, install a recent LTS version and use npm or yarn to manage packages. For Python, use a virtual environment and pip. Configure an editor with linting and debugging tools to speed up development. Install HTTP client utilities (curl, httpie) and JSON formatters to test endpoints. Add environment variable support so you can store credentials and change behavior between development and production.

    Creating and verifying Twilio account and phone numbers for testing

    Sign up for Twilio and verify any required contact information. If you use a trial account, add and verify the phone numbers you’ll call during tests. Purchase an inbound phone number if you need to accept inbound calls and configure its webhook to point to your Vapi scenario endpoint or to an intermediary like ngrok during development. Note the Twilio Account SID and Auth Token and store them securely for use by your Functions and API request tools.

    Configuring ngrok or similar tunnel for local webhook testing

    To receive incoming webhooks to your local machine, install ngrok or an alternative tunneling tool. Start a tunnel that forwards an external HTTPS endpoint to your local port. Use the generated HTTPS URL when configuring Twilio or other webhook providers so they can reach your development server. Keep the tunnel alive during tests and be aware of rate limits or session timeouts on free plans. For production, replace tunneling with a publicly routable endpoint or cloud deployment.

    Preparing n8n instance if following the n8n version of tool response

    If you follow the n8n version of tool responses, ensure your n8n instance is reachable from the services that will call it and that you have credentials configured for Twilio and Google Calendar in n8n. Create workflows that mimic the Vapi tool responses — for example, returning JSON with the expected schema — and expose webhook nodes to accept input. Test your workflows independently before integrating them into Vapi scenarios.

    Vapi Overview

    Here you’ll get acquainted with what Vapi offers, its core concepts, how it fits into call flows, and where resources live to help you build scenarios faster.

    What Vapi provides: voice AI tools, tool orchestration, and prompt vault

    Vapi provides a toolkit for building voice interactions: voice AI processing, a library of tools (Functions, DTMF handlers, transfers, SMS, API request tools), and orchestration that sequences those tools into scenarios. It also offers a Prompt Vault or Tool & Prompt Vault where you store reusable prompts and helper templates so you can reuse language and behavior across scenarios. The platform focuses on making it straightforward to orchestrate tools and external services in a call context.

    Core concepts: tools, functions, scenarios, and tool responses

    Tools are discrete capabilities—play audio, collect DTMF, transfer calls, or call external APIs. Functions are custom code pieces that prepare data, call third-party APIs, or perform logic. Scenarios are sequences of tools that define end-to-end call logic. Tool responses are the structured JSON outputs that signal the platform what to do next (play audio, collect input, call another tool). Understanding how these pieces interact is crucial to building predictable call flows.

    How Vapi fits into a call flow and integrates with external services

    Vapi sits at the orchestration layer: it decides which tool runs next, interprets tool outputs, and sends actions to the telephony provider (like Twilio). When a caller dials in, Vapi triggers a scenario, uses Functions to enrich or look up data, and issues actions such as playing prompts, collecting DTMF, transferring calls, or sending SMS through Twilio. External services are called via API request tools or Functions, and their results feed into the scenario context to influence branching logic.

    Where to find documentation, Tool & Prompt Vault, and example resources

    Within your Vapi workspace or dashboard you’ll find documentation, a Tool & Prompt Vault with reusable assets, and example scenarios that illustrate common patterns. Use these resources to speed up development and borrow best practices. If you have an internal knowledge base or onboarding video, consult it to see real examples that mirror the tutorial flow and tools set.

    Tool Inventory and Capabilities

    This section lists the tools you’ll use, third-party integrations available, limitations to keep in mind, and advice on choosing the right tool for a task.

    List of included tools: Functions, DTMF handler, End Call, Transfers, Send SMS, API request tool

    Vapi includes several core tools: Functions for arbitrary code execution; DTMF handlers to capture and interpret keypad input; End Call for gracefully terminating calls; Transfer tools for moving callers to external numbers or queues; Send SMS to deliver text messages after or during calls; and an API request tool to call REST services without writing custom code. Each serves a clear role in the call lifecycle.

    Third-party integrations: Twilio Flows, Google Calendar, Time API

    Common third-party integrations include Twilio for telephony actions (calls, SMS, transfers), Google Calendar for scheduling and event lookups, and Time APIs for timezone-aware operations. You can also integrate CRMs, ticketing systems, or analytics platforms using the API request tool or Functions. These integrations let you personalize calls, schedule follow-ups, and log interactions.

    Capabilities and limits of each tool: synchronous vs asynchronous, payload sizes, response formats

    Understand which tools operate synchronously (returning immediate results, e.g., DTMF capture) versus asynchronously (operations that may take longer, e.g., external API calls). Respect payload size limits for triggers and tool responses — large media or massive JSON bodies may need different handling. Response formats are typically JSON and must conform to the scenario schema. Some tools can trigger background jobs or callbacks instead of blocking the scenario; choose accordingly to avoid timeouts.

    Choosing the right tool for a given voice/call task

    Match task requirements to tool capabilities: use DTMF handlers to collect numeric input, Functions for complex decision-making or enrichment, API request tool for simple REST interactions, and Transfers when you need to bridge to another phone number or queue. If you need to persist data off-platform or send notifications, attach Send SMS or use Functions to write to your database. Always prefer built-in tools for standard tasks and reserve Functions for bespoke logic.

    Functions Deep Dive

    Functions are where you implement custom logic. This section covers their purpose, how to register them, example patterns, and best practices to keep your scenarios stable and maintainable.

    Purpose of Functions in Vapi: executing code, formatting data, calling APIs

    Functions let you run custom code to format data, call third-party APIs, perform lookups, and create dynamic prompts. They are your extension point when built-in tools aren’t enough. Use Functions to enrich caller context (customer lookup), generate tailored speech prompts, or orchestrate conditional branching based on external data.

    How to create and register a Function with Vapi

    Create a Function in your preferred runtime and implement the expected input/output contract (JSON input, JSON output with required fields). Register it in Vapi by uploading the code or pointing Vapi at an endpoint that executes the logic. Configure authentication so Vapi can call the Function safely. Add versioning metadata so you can rollback or track changes.

    Example Function patterns: data enrichment, dynamic prompt generation, conditional logic

    Common patterns include: data enrichment (fetch customer records by phone number), dynamic prompt generation (compose a personalized message using name, balance, appointment time), and conditional logic (if appointment is within 24 hours, route to a specific flow). Combine these to create high-value interactions, such as fetching a calendar event and then offering to reschedule via DTMF options.

    Best practices: idempotency, error handling, timeouts, and logging

    Make Functions idempotent where possible so retries do not create duplicate side effects. Implement robust error handling that returns structured errors to the scenario so it can branch to fallback behavior. Honor timeouts and keep Functions fast; long-running tasks should be deferred or handled asynchronously. Add logging and structured traces so you can debug failures and audit behavior after the call.

    Make Scenario Walkthrough

    Scenarios define the full call lifecycle. Here you’ll learn the concept, how to build one step-by-step, attach conditions, and the importance of testing and versioning.

    Concept of a Scenario: defining the end-to-end call logic and tool sequence

    A Scenario is a sequence of steps that represents the entire call flow — from initial greeting to termination. Each step invokes a tool or Function and optionally evaluates responses to decide the next action. Think of a Scenario as a script plus logic, where each tool is a stage in that script.

    Step-by-step creation of a scenario: selecting triggers, adding tools, ordering steps

    Start by selecting a trigger (incoming call, scheduled event, or API invocation). Add tools for initial greeting, authentication, intent capture, and any backend lookups. Order steps logically: greet, identify, handle request, confirm actions, and end. At each addition, map expected inputs and outputs so the next tool receives the right context.

    Attaching conditions and branching logic for different call paths

    Use conditions to branch based on data (DTMF input, API results, calendar availability). Define clear rules so the scenario handles edge cases: invalid input, API failures, or unanswered transfers. Visualize the decision tree and keep branches manageable to avoid complexity explosion.

    Saving, versioning, and testing scenarios before production

    Save versions of your Scenario as you iterate so you can revert if needed. Test locally with simulated inputs and in staging with real webhooks using sandbox numbers. Run through edge cases and concurrent calls to verify behavior under load. Only promote to production after automated and manual testing pass.

    Attaching Tools to Scenarios

    This section explains how to wire tools into scenario steps, pass data between them, and use practical examples to demonstrate typical attachments.

    How to attach a tool to a specific step in a scenario

    In the scenario editor, select the step and choose the tool to attach. Configure tool-specific settings (timeouts, prompts, retry logic) and define the mapping between scenario variables and tool inputs. Save the configuration so that when the scenario runs, the tool executes with the right context.

    Mapping inputs and outputs between tools and the scenario context

    Define a consistent schema for inputs and outputs in your scenario context. For example, map caller.phone to your Function input for lookup, and map Function.result.customerName back into scenario.customerName. Use transforms to convert data types or extract nested fields so downstream tools receive exactly what they expect.

    Passing metadata and conversation state across tools

    Preserve session metadata like call ID, start time, or conversation history in the scenario context. Pass that state to Functions and API requests so external systems can correlate logs or continue workflows. Store transient state (like current menu level) and persistent state (like customer preferences) appropriately.

    Examples: attaching Send SMS after End Call, using Functions to prepare API payloads

    A common example is scheduling an SMS confirmation after the call ends: attach Send SMS as a post-End Call step or invoke it from a Function that formats the message. Use Functions to prepare complex API payloads, such as a calendar invite or CRM update, ensuring the payload conforms to the third-party API schema before calling the API request tool.

    Tools Format and Response Structure

    Tool responses must be well-formed so Vapi can act. This section describes the expected JSON schema, common fields, how to trigger actions, and debugging tips.

    Standard response schema expected by Vapi for tool outputs (JSON structure and keys)

    Tool outputs typically follow a JSON schema containing keys like status, content, actions, and metadata. Status indicates success or error, content contains user-facing text or media references, actions tells Vapi what to do next (play, collect, transfer), and metadata carries additional context. Stick to the schema so Vapi can parse responses reliably.

    Common response fields: status, content, actions (e.g., transfer, end_call), and metadata

    Use status to signal success or failure, content to deliver prompts or speech text, actions to request behaviors (transfer to number X, end_call with summary), and metadata to include IDs or tracing info. Include action parameters (like timeout durations or DTMF masks) inside actions so they’re actionable.

    How to format tool responses to trigger actions like playing audio, collecting DTMF, or transferring calls

    To play audio, return an action with type “play” and either a TTS string or a media URL. To collect DTMF, return an action with type “collect” and specify length, timeout, and validation rules. To transfer, return an action type “transfer” with the destination and any bridging options. Ensure your response obeys any required fields and valid values.

    Validating and debugging malformed tool responses

    Validate tool outputs against the expected JSON schema locally before deploying. Use logging and simulated scenario runs to catch malformed responses. If Vapi logs an error, inspect the raw response and compare it to the schema; common issues include missing fields, incorrect data types, or oversized payloads.

    Handling End Call

    Ending calls gracefully is essential. This section explains when to end, how to configure the End Call tool, graceful termination practices, and testing strategies for edge cases.

    When and why to use End Call tool within a scenario

    Use End Call when the interaction is complete, when you need to hand off the caller to another system that doesn’t require a bridge, or to terminate a failed or idle session. It’s also useful after asynchronous follow-ups like sending SMS or scheduling an appointment, ensuring resources are freed.

    Step-by-step: configuring End Call to play final prompts, log call data, and clean up resources

    Configure End Call to play a closing prompt (TTS or audio file), then include actions to persist call summary to your database or notify external services. Make sure the End Call step triggers cleanup tasks: release locks, stop timers, and close any temporary resources. Confirm that any post-call notifications (emails, SMS) are sent before final termination if they are synchronous.

    Graceful termination best practices: saving session context, notifying external services

    Save session context and key metrics before ending the call so you can analyze interactions later. Notify external services with a final webhook or API call that includes call outcome and metadata. If you can’t complete a post-call operation synchronously, record a task for reliable retry and inform the user in the call if appropriate.

    Testing End Call behavior across edge cases (network errors, mid-call errors)

    Simulate network failures, mid-call errors, and abrupt disconnects to ensure your End Call step handles these gracefully. Verify that logs still capture necessary data and that external notifications occur or are queued. Test scenarios that end earlier than expected and ensure cleanup doesn’t assume further steps will run.

    Conclusion

    You’ve seen the main building blocks of Vapi voice automation and how to assemble them into robust scenarios. This final section summarizes next steps and encourages continued experimentation.

    Summary of key steps for building Vapi scenarios with Functions, DTMF, End Call, Transfers, and API integrations

    To build scenarios, prepare accounts and credentials, set up your environment with a secure secrets store, and configure Twilio and ngrok for testing. Use Functions to enrich data and format payloads, DTMF handlers to collect input, Transfers to route calls, End Call to finish sessions, and API tools to integrate external services. Map inputs and outputs carefully, version scenarios, and test thoroughly.

    Recommended next steps: prototype, test, secure, and iterate

    Prototype a simple scenario first (greeting, DTMF menu, and End Call). Test with sandbox and real phone numbers, secure your credentials, and iterate on prompts and branching logic. Add logging and observability so you can measure success and improve user experience. Gradually add integrations like Google Calendar and SMS to increase value.

    Where to get help, how to provide feedback, and how to contribute examples or improvements

    If you run into issues, consult your internal docs or community resources available in your workspace. Provide feedback to your platform team or maintainers with specific examples and logs. Contribute back by adding scenario templates or prompt examples to the Tool & Prompt Vault to help colleagues get started faster.

    Encouragement to experiment with the Tool & Prompt Vault and share successful scenario templates

    Experiment with the Tool & Prompt Vault to reuse effective prompts and template logic. Share successful scenario templates and Functions with your team so everyone benefits from proven designs. By iterating and sharing, you’ll accelerate delivery and create better, more reliable voice experiences for your users.

    If you want to implement Chat and Voice Agents into your business to reduce missed calls, book more appointments, save time, and make more revenue, book a discovery call here: https://brand.eliteaienterprises.com/widget/bookings/elite-ai-30-min-demo-call

  • Tools in Vapi! A Step-by-Step Full Guide – What are Tools? How to Set Up with n8n?

    Tools in Vapi! A Step-by-Step Full Guide – What are Tools? How to Set Up with n8n?

    Tools in Vapi! A Step-by-Step Full Guide – What are Tools? How to Set Up with n8n? by Henryk Brzozowski walks you through why tools matter, the main tool types, and how to build and connect your first tool with n8n. Umm, it’s organized with timestamps so you can jump to creating a tool, connecting n8n, improving and securing tools, and transferring functions. You’ll get a practical, hands-on walkthrough that keeps things light and useful.

    You’ll also see concrete tool examples like searchKB for knowledge queries, checkCalendar and bookCalendar for availability and bookings, sendSMS for links, and transferCustomerCare for escalations, plus the booking flow that confirms “You’ve been booked” to close calls. Uhh, like, that makes it easy to picture real setups. By the end, you’ll know how to set up, secure, and improve tools so your voice AI agents behave the way you want.

    What are Tools in Vapi?

    Tools in Vapi are the mechanisms that let your voice AI agent do more than just chat: they let it take actions. When you wire a tool into Vapi, you extend the agent’s capabilities so it can query your knowledge base, check and create calendar events, send SMS messages, or transfer a caller to human support. In practice, a tool is a defined interface (name, description, parameters, and expected outputs) that your agent can call during a conversation to accomplish real-world tasks on behalf of the caller.

    Definition of a tool in Vapi and how it extends agent capabilities

    A tool in Vapi is a callable function with a strict schema: it has a name, a description of what it does, input parameters, and a predictable output shape. When your conversational agent invokes a tool, Vapi routes the call to your integration (for example, to n8n or a microservice), receives the result, and resumes the dialog using that result. This extends the agent from purely conversational to action-oriented — you can fetch data, validate availability, create bookings, and more — all in the flow of the call.

    Difference between built-in functions and external integrations

    Built-in functions are lightweight, internal capabilities of the Vapi runtime — things like rendering a small template, ending a call, or simple local logic. External integrations (tools) are calls out to external systems: knowledge APIs, calendar providers, SMS gateways, or human escalation services. Built-in functions are fast and predictable; external integrations are powerful and flexible but require careful schema design, error handling, and security controls.

    How tools interact with conversation context and user intent

    Tools are invoked based on the agent’s interpretation of user intent and the current conversation context. You should design tool calls to be context-aware: include caller name, timezone, reason for booking, and the agent’s current hypothesis about intent. After a tool returns, the agent uses the result to update the conversational state and decide the next prompt. For example, if checkCalendar returns “busy,” the agent should ask follow-up questions, suggest alternatives, and only call bookCalendar after the caller confirms.

    Examples of common tool use cases for voice AI agents

    Common use cases include: answering FAQ-like queries by calling searchKB, checking available time slots with checkCalendar, creating callbacks by calling bookCalendar, sending a link to the caller’s phone using sendSMS, and transferring a call to a human via transferCustomerCare. Each of these lets your voice agent complete a user task rather than just give an answer.

    Overview of the Core Tools Provided

    This section explains the core tools you’ll likely use in Vapi and what to expect when you call them.

    searchKB: purpose, basic behavior, and typical responses

    searchKB is for querying your knowledge base to answer user questions — opening hours, product details, policies, and so on. You pass a free-text query; the tool returns relevant passages, a confidence score, and optionally a short synthesized answer. Typical responses are a list of matching entries (title + snippet) and a best-effort answer. Use searchKB to ground your voice responses in company documentation.

    checkCalendar: purpose and input/output expectations

    checkCalendar verifies whether a requested time is available for booking. You send a requestedTime parameter in the ISO-like format (e.g., 2024-08-13T21:00:00). The response should indicate availability (true/false), any conflicting events, and optionally suggested alternative slots. Expect some latency while external calendar providers are queried, and handle “unknown” or “error” states with a friendly follow-up.

    bookCalendar: required parameters and booking confirmation flow

    bookCalendar creates an event on the calendar. Required parameters are requestedTime, reason, and name. The flow: you check availability first with checkCalendar, then call bookCalendar with a validated time and the caller’s details. The booking response should include success status, event ID, start/end times, and a human-friendly confirmation message. On success, use the exact confirmation script: “You’ve been booked and I’ll notify Henryk to prepare for your call…” then move to your closing flow.

    sendSMS: when to use and content considerations

    sendSMS is used to send a short message to the caller’s phone, typically containing a link to your website, a booking confirmation, or a pre-call form. Keep SMS concise, include the caller’s name if possible, and avoid sensitive data. Include a clear URL and a short reason: “Here’s the link to confirm your details.” Track delivery status and retry or offer alternatives if delivery fails.

    transferCustomerCare: when to escalate to a human and optional message

    transferCustomerCare is for handing the caller to a human team member when the agent can’t handle the request or the caller explicitly asks for a human. Provide a destination (which team or queue) and an optional message to the customer: “I am transferring to our customer care team now 👍”. When you transfer, summarize the context for the human agent and notify the caller of the handover.

    Tool Definitions and Parameters (Detailed)

    Now dig into concrete parameters and example payloads so you can implement tools reliably.

    searchKB parameters and example query payloads

    searchKB parameters:

    • query (string): the full user question or search phrase.

    Example payload: { “tool”: “searchKB”, “parameters”: { “query”: “What are your opening hours on weekends?” } }

    Expected output includes items: [ { title, snippet, sourceId } ] and optionally answer: “We are open Saturday 9–2 and closed Sunday.”

    checkCalendar parameters and the expected date-time format (e.g., 2024-08-13T21:00:00)

    checkCalendar parameters:

    • requestedTime (string): ISO-like timestamp with date and time, e.g., 2024-08-13T21:00:00. Include the caller’s timezone context separately if possible.

    Example payload: { “tool”: “checkCalendar”, “parameters”: { “requestedTime”: “2024-08-13T21:00:00” } }

    Expected response: { “available”: true, “alternatives”: [], “conflicts”: [] }

    Use consistent date-time formatting and normalize incoming user-specified times into this canonical format before calling the tool.

    bookCalendar parameters: requestedTime, reason, name and success acknowledgement

    bookCalendar parameters:

    • requestedTime (string): 2024-08-11T21:00:00
    • reason (string): brief reason for the booking
    • name (string): caller’s full name

    Example payload: { “tool”: “bookCalendar”, “parameters”: { “requestedTime”: “2024-08-11T21:00:00”, “reason”: “Discuss Voice AI demo”, “name”: “Alex Kowalski” } }

    Expected successful response: { “success”: true, “eventId”: “evt_12345”, “start”: “2024-08-11T21:00:00”, “end”: “2024-08-11T21:30:00”, “message”: “You’ve been booked and I’ll notify Henryk to prepare for your call…” }

    On success, follow that exact phrasing, then proceed to closing.

    sendSMS parameters and the typical SMS payload containing a link

    sendSMS parameters:

    • phoneNumber (string): E.164 or region-appropriate phone
    • message (string): the SMS text content

    Typical SMS payload: { “tool”: “sendSMS”, “parameters”: { “phoneNumber”: “+48123456789”, “message”: “Hi Alex — here’s the link to confirm your details: https://example.com/confirm. See you soon!” } }

    Keep SMS messages short, personalized, and include a clear call to action. Respect opt-out rules and character limits.

    transferCustomerCare destinations and optional message to customer

    transferCustomerCare parameters:

    • destination (string): the team or queue identifier
    • messageToCustomer (string, optional): “I am transferring to our customer care team now 👍”

    Example payload: { “tool”: “transferCustomerCare”, “parameters”: { “destination”: “customer_support_queue”, “messageToCustomer”: “I am transferring to our customer care team now 👍” } }

    When transferring, include a short summary of the issue for the receiving agent and confirm to the caller that the handover is happening.

    Conversation Role and Prompting Best Practices

    Your conversational style matters as much as correct tool usage. Make sure the agent sounds human, helpful, and consistent.

    Persona: Hellen the receptionist — tone, phrasing, and allowed interjections like ‘Umm’ and ‘uhh’

    You are Hellen, a friendly and witty receptionist. Keep phrasing casual and human: use slight hesitations like “Umm” and “uhh” in moderation to sound natural. For example: “Umm, let me check that for you — one sec.” Keep your voice upbeat, validate interest, and add small humor lines when appropriate.

    How to validate interest, keep light and engaging, and use friendly humor

    When a caller expresses interest, respond with enthusiasm: “That’s great — I’d love to help!” Use short, playful lines that don’t distract: “Nice choice — Henryk will be thrilled.” Always confirm intent before taking actions, and use light humor to build rapport while keeping the conversation efficient.

    When to use tools versus continuing the dialog

    Use a tool when you need factual data or an external action: checking availability, creating a booking, sending a link, or handing to a human. Continue the dialog locally for clarifying questions, collecting the caller’s name, or asking for preferred times. Don’t call bookCalendar until you’ve confirmed the time with the caller and validated availability with checkCalendar.

    Exact scripting guidance for booking flows including asking for caller name and preferred times

    Follow this exact booking script pattern:

    1. Validate intent: “Would you like to book a callback with Henryk?”
    2. Ask for name: “Great — can I have your name, please?”
    3. Ask for a preferred time: “When would you like the callback? You can say a date and time or say ‘tomorrow morning’.”
    4. Normalize time and check availability: call checkCalendar with requestedTime.
    5. If unavailable, offer alternatives: “That slot’s taken — would 10:30 or 2:00 work instead?”
    6. After confirmation, call bookCalendar with requestedTime, reason, and name.
    7. On success, say: “You’ve been booked and I’ll notify Henryk to prepare for your call…” then close.

    Include pauses and phrases like “Umm” or “uhh” where natural: “Umm, can I get your name?” This creates a friendly, natural flow.

    Step-by-Step: Create Your First Tool in Vapi

    Build a simple tool by planning schema, defining it in Vapi, testing payloads, and iterating.

    Plan the tool: name, description, parameters and expected outputs

    Start by writing a short name and description, then list parameters (name, type, required) and expected outputs (success flag, data fields, error codes). Example: name = searchKB, description = “Query internal knowledge,” parameters = { query: string }, outputs = { results: array, answer: string }.

    Define the tool schema in Vapi: required fields and types

    In Vapi, a tool schema should include tool name, description, parameters with types (string, boolean, datetime), and which are required. Also specify response schema so the agent knows how to parse the returned data. Keep the schema minimal and predictable.

    Add sample payloads and examples for testing

    Create example request and response payloads (see previous sections). Use these payloads to test your integration and to help developers implement the external endpoint that Vapi will call.

    Test the tool inside a sandbox conversation and iterate

    Use a sandbox conversation in Vapi to call the tool with your sample payloads and inspect behavior. Validate edge cases: missing parameters, unavailable external service, and slow responses. Iterate on schema, error messages, and conversational fallbacks until the flow is smooth.

    How to Set Up n8n to Work with Vapi Tools

    n8n is a practical automation layer for mapping Vapi tool calls to real APIs. Here’s how to integrate.

    Overview of integration approaches: webhooks, HTTP requests, and n8n credentials

    Common approaches: Vapi calls an n8n webhook when a tool is invoked; n8n then performs HTTP requests to external APIs (calendar, SMS) and returns a structured response. Use n8n credentials or environment variables to store API keys and secrets securely.

    Configure an incoming webhook trigger in n8n to receive Vapi events

    Create an HTTP Webhook node in n8n to receive tool invocation payloads. Configure the webhook path and method to match Vapi’s callback expectations. When Vapi calls the webhook, n8n receives the payload and you can parse parameters like requestedTime or query.

    Use HTTP Request and Function nodes to map tool inputs and outputs

    After the webhook, use Function or Set nodes to transform incoming data into the external API format, then an HTTP Request node to call the provider. After receiving the response, normalize it back into Vapi’s expected response schema and return it from the webhook node.

    Secure credentials in n8n using Environment Variables or n8n Credentials

    Store API keys in n8n Credentials or environment variables rather than hardcoding them in flows. Restrict webhook endpoints and use authentication tokens in Vapi-to-n8n calls. Rotate keys regularly and keep minimal privileges on service accounts.

    Recommended n8n Flows for Each Tool

    Design each flow to transform inputs, call external services, and return normalized responses.

    searchKB flow: trigger, transform query, call knowledge API, return results to Vapi

    Flow: Webhook → Parse query → Call your knowledge API (or vector DB) → Format top matches and an answer → Return structured JSON with results and answer. Include confidence scores and source identifiers.

    checkCalendar flow: normalize requestedTime, query calendar provider, return availability

    Flow: Webhook → Normalize requestedTime and timezone → Query calendar provider (Google/Outlook) for conflicts → Return available: true/false plus alternatives. Cache short-term results if needed to reduce latency.

    bookCalendar flow: validate time, create event, send confirmation message back to Vapi

    Flow: Webhook → Re-check availability → If available, call calendar API to create event with attendee (caller) and description → Return success, eventId, start/end, and message. Optionally trigger sendSMS flow to push confirmation link to the caller.

    sendSMS flow: format message with link, call SMS provider, log delivery status

    Flow: Webhook → Build personalized message using name and reason → HTTP Request to SMS provider → Log delivery response to a database → Return success/failure and provider delivery ID. If SMS fails, return error that prompts agent to offer alternatives.

    transferCustomerCare flow: notify human team, provide optional handoff message to the caller

    Flow: Webhook → Send internal notification to team (Slack/email/CRM) containing call context → Place caller into a transfer queue if available → Return confirmation to Vapi that transfer is in progress with a short message to the caller.

    Mapping Tool Parameters to External APIs

    Mapping is critical to ensure data integrity across systems.

    Common data transformations: date-time normalization and timezone handling

    Always normalize incoming natural-language times to ISO timestamps in the caller’s timezone. Convert to the calendar provider’s expected timezone before API calls. Handle daylight saving time changes and fallback to asking the caller for clarification when ambiguous.

    How to map bookCalendar fields to Google Calendar or Outlook API payloads

    Map requestedTime to start.dateTime, set an end based on default meeting length, use name as summary or an attendee, and include reason in the description. Include timezone fields explicitly. Example mapping: requestedTime -> start.dateTime, end = start + 30 mins, name -> attendees[0].email (when known) or summary: “Callback with Alex”.

    Best practices for including the caller’s name and reason in events

    Place the caller’s name in the event summary and the reason in the description so humans scanning calendars see context. If you have the caller’s phone/email, add as attendee to send a calendar invite automatically.

    Design patterns for returning success, failure, and error details back to Vapi

    Return a consistent response object: success (bool), code (string), message (human-friendly), details (optional technical info). For transient errors, include retry suggestions. For permanent failures, include alternative suggestions for the caller.

    Scheduling Logic and UX Rules

    Good UX prevents frustration and reduces back-and-forth.

    Always check availability before attempting to book and explain to the caller

    You should always call checkCalendar before bookCalendar. Tell the caller you’re checking availability: “Umm, I’ll check Henryk’s calendar — one sec.” If unavailable, offer alternatives immediately.

    Use current time as guideline and prevent booking in the past

    Use the current time (server or caller timezone) to prevent past bookings. If a caller suggests a past time, gently correct them: “Looks like that time has already passed — would tomorrow at 10:00 work instead?”

    Offer alternative times on conflict and confirm user preference

    When a requested slot is busy, proactively suggest two or three alternatives and ask the caller to pick. This reduces friction: “That slot is booked — would 10:30 or 2:00 work better for you?”

    Provide clear closing lines on success: ‘You’ve been booked and I’ll notify Henryk to prepare for your call…’

    On successful booking, use the exact confirmation phrase: “You’ve been booked and I’ll notify Henryk to prepare for your call…” Then ask if there’s anything else: “Is there anything else I can help with?” If not, end the call politely.

    Conclusion

    You now have a full picture of how tools in Vapi turn your voice agent into a productive assistant. Design precise tool schemas, use n8n (or your integration layer) to map inputs and outputs, and follow conversational best practices so Hellen feels natural and helpful.

    Summary of the key steps to design, build, and integrate Vapi tools with n8n

    Plan your tool schemas, implement endpoints or n8n webhooks, normalize inputs (especially date-times), map to external APIs, handle errors gracefully, and test thoroughly in a sandbox before rolling out.

    Checklist of best practices to follow before going live

    • Define clear tool schemas and sample payloads.
    • Normalize time and timezone handling.
    • Check availability before booking.
    • Personalize messages with caller name and reason.
    • Secure credentials and webhook endpoints.
    • Test flows end-to-end in sandbox.
    • Add logging and analytics for iterative improvement.

    Next steps for teams: create a sandbox tool, build n8n flows, and iterate based on analytics

    Start small: create a sandbox searchKB or checkCalendar tool, wire it to a simple n8n webhook, and iterate. Monitor usage and errors, then expand to bookCalendar, sendSMS, and transfer flows.

    Encouragement to keep dialog natural and use the Hellen receptionist persona for better UX

    Keep conversations natural and friendly — use the Hellen persona: slightly witty, human pauses like “Umm” and “uhh”, and validate the caller’s interest. That warmth will make interactions smoother and encourage callers to complete tasks with your voice agent.

    You’re ready to build tools that make your voice AI useful and delightful. Start with a small sandbox tool, test the flows in n8n, and iterate — Hellen will thank you, and Henryk will be ready for those calls.

    If you want to implement Chat and Voice Agents into your business to reduce missed calls, book more appointments, save time, and make more revenue, book a discovery call here: https://brand.eliteaienterprises.com/widget/bookings/elite-ai-30-min-demo-call

Social Media Auto Publish Powered By : XYZScripts.com