Cresta vs Sierra (2026)

As a single intelligent layer over telephony, chat, CRM and knowledge systems, Cresta also takes action in them. Agents connect to CRM, billing and scheduling systems through secure API based function calling, for example disputing a fraudulent charge, replacing a lost card and shipping it to a new address. Integrations are a product area of their own, and Cresta states it does not require ripping out existing telephony.

Sourcecresta.com/integrationsread 2026-09-05

Agents reach the customer's systems of record to carry out end to end transactions, including card and ACH payments, returns, authentication and cancellation saves, and those system interactions are held deterministic and bound by policy. Agent Studio offers ready integrations and an integration framework for proprietary systems, and the Agent SDK builds the rest, so the range of connected systems depends on what each team sets up. Integrations also route a conversation to the customer's care team with its full context.

Sourcesierra.ai/product/agent-sdkread 2026-09-05

Opera, the no-code orchestration layer, runs multi-step work, and the AI Agent lifecycle has its own set of surfaces, Discover, Build, Test and Deploy, Optimize and Omnichannel, with an Agent Operations Center for production. In one example an agent runs a complete chain in one conversation, disputing a fraudulent charge, replacing a lost card and shipping it to a new address, and guided workflows route an interaction through an approved procedure step by step.

Sourcecresta.com/operaread 2026-09-05

Agents are put together from skills such as triage, respond and confirm, combined into multistep workflows for a specific use case. In Agent Studio a team defines those journeys step by step or has AI generate them from its existing operating procedures, and Ghostwriter builds or changes an agent from a description of how it should behave. Flexibility is set per workflow, so a team can move between deterministic execution and open ended reasoning on the same agent.

Sourcesierra.ai/product/agent-sdkread 2026-09-05

Work reaches Cresta from the customer's existing CCaaS and telephony estate as well as from surfaces Cresta owns. Omnichannel, under AI Agent, covers voice, chat, SMS and email, each optimized for the channel's demands, the AI Receptionist handles inbound calls, and Cresta states it does not require ripping out existing telephony. Knowledge Agent also listens continuously through a live conversation.

Sourcecresta.com/ai-agent-omnichannelread 2026-09-05

An agent is built once and deployed across chat, phone, email, SMS and messaging, with the same skills and policies applying on each. A single agent working across every channel is the core idea of the platform.

Sourcesierra.ai/product/agent-sdkread 2026-09-05

Knowledge lives in a store Cresta maintains itself. Content is consolidated and synced from multiple systems into a single source of truth with centralized management and real-time delivery, and the same store serves both human and AI agents. Answers are cited and grounded in approved knowledge rather than open-ended generation, with guarded output and custom redaction applied on top.

Sourcecresta.com/knowledge-agentread 2026-09-05

Agents ground answers in the customer's own content through retrieval built into Agent OS, and the Agent Data Platform joins that knowledge with customer context from other systems. In Agent Studio a team connects its knowledge sources and views and edits help center content, FAQs and policies. Sierra spots common themes missing from the knowledge base and drafts new articles from how care representatives resolved edge cases, so the store grows without manual updates.

Sourcesierra.ai/product/agent-sdkread 2026-09-05

Shared memory keeps critical context across channels, handoffs and between human and AI agents, and customer history and preferences personalize each interaction into one continuous conversation. That names a scope, the customer journey, but no lifetime, retention or deletion path is published.

Sourcecresta.com/ai-agentread 2026-09-30

Agents personalize each conversation from agent memory and the customer's profile, and the Agent Data Platform brings together what the agent knows about a specific customer across sessions, channels and systems, so context carries from one conversation to the next. How long that memory lasts, and whether a customer's record of it can be viewed or cleared, is not public.

Sourcesierra.ai/product/insightsread 2026-09-05

Cresta's controls apply before and during the action. Agents run inside an approved scope of intents and actions with blocks on commitments they should not make, advanced guardrails against hallucination, guided workflows that hold an interaction to approved playbooks, and custom PII redaction. There are also built-in quality and risk controls, which subject every model to post-processing, double-checks and live performance tracking.

Sourcecresta.com/trustread 2026-09-05

Sierra wraps its models in supervisory layers that check outputs against scope and policy before the agent responds, to reduce hallucination and prevent abuse. Access to systems of record is deterministic and controlled, and the customer's policies and security procedures are enforced outside the model. Flexibility settings on each workflow limit how far the agent may improvise.

Sourcesierra.ai/product/trust-and-reliabilityread 2026-09-05

Cresta publishes both its compliance posture and its access controls on a live SafeBase trust center. It holds ISO/IEC 27001, 27701 and 42001:2023, plus SOC 2 and SOC 3, and covers HIPAA, PCI DSS and TISAX, with GDPR, CCPA and CPRA for privacy. Audit reports and certificates are available through a request path, alongside a published red teaming report, a HIPAA report, a network diagram, and SIG Lite and VSA Core self-assessments.

Access control covers logical access control, multi-factor authentication under product security, and separate databases per customer with no data commingling. Supporting practices include a secure development lifecycle, third-party penetration testing scored with CVSS, a responsible disclosure program triaged within 24 hours, and active subprocessor and vulnerability notification feeds.

Sourcetrust.cresta.comread 2026-09-05

Sierra holds ISO/IEC 27001:2022 and ISO/IEC 42001:2023 certificates, a SOC 2 Type II report, a HIPAA attestation for 2026 and PCI DSS Level 1 service provider certification. Its trust center also covers the European and California privacy laws, the CSA STAR registry and FedRAMP High, with controls and policies shared on request.

Personal information shared with an agent is encrypted and masked automatically, filters block topics and keywords a company puts off limits, and cardholder data runs on dedicated PCI infrastructure that never touches Sierra's core platform, models or storage. Customer data is never used to train models or shared with other customers. Who inside a customer's own organization can build, edit or publish an agent, through single sign on, roles or permissions, is not public.

Sourcesierra.ai/product/trust-and-reliabilityread 2026-09-05

Explainability is built into Cresta's models, using Chain-of-Thought and Model-based Critique to make AI outputs interpretable and accountable, with every model subject to post-processing, double-checks and live performance tracking. Conversation Intelligence, Insights, AI Analyst, Quality Management and Coach are named products that analyze every conversation rather than a sample, and an Agent Operations Center monitors agents in production.

Sourcecresta.com/trustread 2026-09-05

Every agent action can be traced to its reasoning, with the knowledge sources and systems it used, and developers inspect API calls and logic traces while Agent Studio shows a live trace of each decision, tool call and response during a build.

Insights reports on CSAT, resolution and other metrics with custom reports, tags and categorizes conversations automatically, flags the ones that need a person's attention and sends alerts on abuse attempts or performance drops to a team's existing tools.

Explorer answers questions about thousands of conversations with themes, data and links to the conversations behind each finding, and delivers a weekly briefing on its own.

Sourcesierra.ai/product/insightsread 2026-09-05

No residency, regional hosting, VPC, single-tenant or self-hosted option is published. The trust center names Amazon Web Services for infrastructure and lists OpenAI, Deepgram, Datadog, Cloudflare and Google Cloud as subprocessors. Its sections on data security, access control, network security, legal and infrastructure include no residency entry, and there is no region menu. Cresta says the platform is available on Google Cloud and Amazon Web Services.

Sourcetrust.cresta.comread 2026-09-05

Sierra hosts the platform as SaaS. Each subprocessor carries its own processing location on the trust center, and customers do not pick a region. There is no VPC, single tenant or on premises option. The FedRAMP High commitment points to separate government infrastructure, though no choice of residency regions is offered.

Sourcesierra.ai/product/trust-and-reliabilityread 2026-09-05

Cresta sells a named set of prebuilt agents and assistants the customer adopts as units, each a product of its own. AI Agent comes with Discover, Build, Test and Deploy, Optimize, Omnichannel, Agent Operations Center and AI Receptionist, Agent Assist with Knowledge Agent, AI Summaries, Behavioral Guidance and Typing Efficiency, and Conversation Intelligence with Insights, AI Analyst, Automation Discovery, Coach, Quality Management and Training Simulator. There is no browsable marketplace of cloneable agents.

Sourcecresta.com/trustread 2026-09-05

The Agent SDK ships with a range of AI skills and systems integrations to help customers go live faster, and skills such as triage, respond and confirm work as reusable building blocks. Customers assemble these pieces themselves. There are no named prebuilt agents, templates, library or marketplace.

Sourcesierra.ai/product/agent-sdkread 2026-09-05

Several model providers sit behind the product: Cresta's subprocessor list names OpenAI and, in a later notification, Anthropic as natural language API providers, Fireworks.ai for LLM model inference, and Deepgram, ElevenLabs and Cartesia AI for speech. Routing is internal to Cresta, and no model selection, override or bring your own model control is offered to the customer. Google Cloud, Cloudflare and Datadog on the same list provide infrastructure.

Sourcetrust.cresta.comread 2026-09-05

Agents draw on more than fifteen frontier, open weight and proprietary models chosen per job, and Sierra switches between LLM providers automatically to optimize performance and keep running during a provider outage. Model serving runs through subprocessors that include Anthropic, Google, AWS, Baseten, Fireworks AI, Together AI and Modal. Routing happens inside Sierra, and neither customers nor admins choose the model.

Sourcesierra.ai/blog/constellation-of-modelsread 2026-09-05

Model Context Protocol support is stated, but whether it exposes Cresta as an MCP server a customer can build on or connects Cresta to the customer's own servers is not published. API based function calling links Cresta to the customer's CRM, billing and scheduling systems. There is no public API reference or SDK for Cresta's own platform, and the Help Center sits at docs.cresta.com.

Sourcecresta.com/integrationsread 2026-09-05

Developers build, customize and deploy agents with the Agent SDK, which comes with documentation, interactive training and a development pipeline. Agent OS adds ready made tooling for building, deploying and managing agents. There is no public API reference or MCP server for the platform itself, so developers work through the SDK.

Sourcesierra.ai/product/agent-sdkread 2026-09-05

Testing ships as named product surfaces. Synthetic Customers sits beside a Test and Deploy stage in the AI Agent lifecycle, which runs Discover, Build, Test and Deploy, then Optimize, with a Training Simulator under Conversation Intelligence and an Agent Operations Center for production. Agents run against edge cases, adversarial scenarios and synthetic customers built from historical conversation data before deployment, and optimization continues afterwards. What gets tested is the customer's own agent.

Sourcecresta.com/synthetic-customersread 2026-09-05

Agent Studio simulates conversations and scores the agent against defined outcomes, and a team builds a regression test suite that runs before each new version of the agent is released.

Voice agents are tested for transcription, background noise and speaker variation before going live, and the Agent SDK checks behavior across a wide range of scenarios in a development pipeline, so definitions are not edited live.

After launch, Insights runs experiments on variations of agent behavior such as handoff rules or levels of determinism, and Explorer compares performance before and after a change Ghostwriter has made.

Sourcesierra.ai/product/agent-studioread 2026-09-05

Knowledge Agent reads the browser the human agent is working in. It runs as a persistent browser-based panel that follows the human agent, incorporates real-time browser context such as account status, order history or loyalty tier, and surfaces cited answers and step-by-step guided workflows so the agent sticks to approved playbooks. The person takes every action, and the agent does not operate an interface itself.

Sourcecresta.com/knowledge-agentread 2026-09-05

Agents act on the customer's systems through API integrations built with the SDK, kept deterministic and bound by policy, and deploy across chat, phone, email, SMS and messaging. Browser control, a virtual desktop and operation of software without a programmatic interface are not part of the platform.

Sourcesierra.ai/product/agent-sdkread 2026-09-05