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Voice Agents

Voice AI Agent Development

FISTA Solutions builds voice AI agents for real phone workflows: answering inbound calls, booking and confirming appointments, taking structured intake, and running outbound reminders — engineered for low latency, interruption handling, accurate capture, and immediate transfer to a human when it matters.

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150+
projects delivered
50+
companies served
99.9%
verified uptime
47%
efficiency gains
12+
countries reached

What we build

What does a voice AI agent do?

Voice agents answer and route inbound calls, book and confirm appointments against live availability, capture structured intake with confirmation, run outbound reminders with opt-out handling, and transfer to a human with full context whenever the caller asks or the conversation requires it.

  1. 01

    Inbound answering and routing

    Answers on the first ring, understands intent, and routes or resolves, replacing rigid phone menus.

    Inbound
  2. 02

    Appointment booking

    Books and confirms against live availability with rules honored, including reschedules and cancellations.

    Scheduling
  3. 03

    Structured intake

    Captures names, identifiers, and details with read-back confirmation on anything critical.

    Intake
  4. 04

    Outbound reminders

    Confirmations, reminders, and follow-ups with opt-out handling and jurisdictional calling rules respected.

    Outbound
  5. 05

    Human transfer

    Immediate warm transfer with conversation context, on caller request or on detected difficulty.

    Escalation

Requirements

What guardrails does a voice agent need?

Voice is unforgiving: latency is audible, misheard digits cause real errors, and callers expect a human on request. The guardrails are therefore technical as much as procedural — sub-second response, confirmation of critical data, and instant transfer.

Voice Agents: requirements and how FISTA Solutions builds to them
GuardrailWhy it mattersHow FISTA implements it
LatencyPauses over a second feel broken on a call.Streaming speech recognition and synthesis, partial-response strategies, and latency budgets measured per turn.
Interruption handlingPeople talk over phone systems.Barge-in support with clean cancellation, so the agent stops speaking and listens rather than talking over the caller.
Critical data accuracyMisheard digits and names cause real harm.Read-back confirmation on identifiers, dates, and amounts, with spelled confirmation where ambiguity is likely.
Human on requestCallers must be able to reach a person.Immediate transfer on request, with context passed and no loop-back into automation.
Consent and recordingRecording and outbound calling are regulated.Disclosure at call start, consent captured per jurisdiction, and calling-time rules enforced for outbound.

Where AI fits

Where should a voice agent start?

Start with after-hours answering or appointment confirmation. Both have clear value, bounded conversation scope, and a low cost of imperfection, which is the right place to tune latency and capture accuracy.

  1. 01

    1. Cover after hours

    Calls currently going to voicemail are pure upside, with a bounded conversation scope.

  2. 02

    2. Confirm appointments outbound

    Short, structured calls that reduce no-shows and validate capture accuracy.

  3. 03

    3. Book appointments inbound

    Live availability integration once capture and latency are proven.

  4. 04

    4. Take structured intake

    Longer conversations with read-back confirmation on every critical field.

  5. 05

    5. Handle overflow

    Peak-hour overflow answering once transfer and escalation behavior is trusted.

Cost and timeline

How much does a voice agent cost, and how long does it take?

Cost is driven by telephony integration, conversation complexity, and call volume; timeline by carrier and platform integration. FISTA does not quote blind: the scoping call returns an agent design, a latency plan, and a phased estimate.

Per-minute inference and telephony cost makes volume a real operating expense, so FISTA models cost per call during design and tunes model routing and conversation length accordingly.

Tuning against real calls is what makes a voice agent acceptable. Accents, background noise, and interruptions only show up in production audio, so a measured tuning period is planned rather than hoped for.

Send the scope you have, even if it is a paragraph. You get a written brief, an architecture sketch, and a phased estimate before any commitment.

Get a scoped quote

Delivery

How does FISTA deliver an AI agent into production?

FISTA delivers agents in four gated phases: a discovery sprint that picks the workflow and writes the agent specification, a design that names tools, permissions, and approval points, a build with an evaluation harness and shadow runs on real work, and a production release with traces, dashboards, and rollback.

  1. 1

    Select and specify

    Choose the workflow with a measurable outcome, map its systems and edge cases, and write the agent spec with success metrics.

    Output

    Agent specification, golden test set

  2. 2

    Design the guardrails

    Tool inventory with least-privilege scopes, approval gates, escalation paths, data handling, and the evaluation plan.

    Output

    Tool and permission matrix

  3. 3

    Build and shadow-run

    Implement tools as MCP servers or connectors, iterate against the evaluation harness, and run in shadow mode on live inputs.

    Output

    Shadow-mode results, eval scores

  4. 4

    Release and observe

    Graduated rollout, full traces, cost and quality dashboards, on-call runbook, and a change process that re-runs the evals.

    Output

    Production agent with SLOs

Why FISTA

Why build your voice agent with FISTA Solutions?

FISTA builds voice agents tuned on real call audio, with read-back confirmation on anything critical and an immediate path to a human. Work is contracted through a US entity with full IP assignment.

Voice Agents specifics

  • Latency budgets are measured per turn, because a delay that reads fine in text feels broken on a call.
  • Barge-in is supported properly: the agent stops and listens rather than talking over the caller.
  • Identifiers, dates, and amounts are read back for confirmation before anything is committed.
  • A caller asking for a person gets one immediately, with context, and is never looped back into automation.

How FISTA engineers

  • Spec-Driven Development: every deliverable starts as a written specification with acceptance criteria, so scope is testable before it is built.
  • AI-native delivery: engineers direct coding agents under review gates and evaluation harnesses, compressing build time without loosening verification.
  • Official Anthropic partner, with production experience across Claude, OpenAI, Google, and open-weight models, chosen per workload rather than by default.
  • One accountable delivery lead, weekly demos on your environment, and code in your repositories from week one.

What you get as a client

  • 150+ projects delivered for 50+ companies across 12+ countries since 2017, with 99.9% verified uptime on systems we operate.
  • A US entity (FISTA Solutions Inc., Wilmington, Delaware) for contracting, invoicing, and IP assignment, with an engineering center in Faisalabad, Pakistan for cost-efficient senior capacity.
  • US business-hours overlap for standups and reviews; written decision logs so nothing depends on a meeting you missed.
  • Flexible engagement: fixed-scope build, embedded forward deployed engineers, or a dedicated team that you can scale month to month.

Clear answers

What teams ask before deploying agents.

Straightforward guidance for evaluating scope, fit, and the next step.

01Do callers accept talking to an AI?

Generally yes when it is disclosed, responds quickly, understands interruptions, and transfers to a person on request. Callers object to being trapped, not to automation that resolves their reason for calling.

02How accurate is capture of names and numbers?

Critical fields are read back for confirmation, with spelled confirmation where ambiguity is likely, so accuracy is enforced by the conversation design rather than left to recognition alone.

03Can it work with our phone system?

Yes, with common telephony and contact center platforms via their supported integrations, including warm transfer to your existing queues with context.

04Can it make outbound calls?

Yes, for reminders, confirmations, and follow-ups, with calling-time rules, consent, and opt-out handling enforced per jurisdiction.

05How long until it is answering calls?

A bounded use case like after-hours answering or confirmations typically goes live within weeks, followed by a tuning period on real call audio.

Continue exploring

Related capabilities

Customer support AI agentsThe same grounding and escalation discipline across text channels.Scheduling AI agentsCalendar and capacity-aware booking agents.How to build an AI voice agentField note on voice agent architecture and pitfalls.

Scoped in writing before you commit

Answer every call, including the ones at 2am.

Bring the call flow and your phone platform. The scoping call returns an agent design, a latency plan, and a phased estimate.

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