# Sierra — Enterprise platform for customer-service AI agents across voice, chat, email and messaging, priced by outcome. > Source: The Agents Index — https://theagentsindex.com/sierra (structured, researched, re-verified) > Facts last verified: 2026-09-26 Sierra is an enterprise platform for building customer-experience AI agents that resolve requests across voice, chat, email and messaging and act in systems of record. Agents are built in a no-code studio or via its Agent SDK. | Fact | Value | | --- | --- | | Website | https://sierra.ai | | Price | At Sierra, we've pioneered an entirely new business model - outcome-based pricing - where you pay only when the software achieves specific, valuable outcomes. | | Free tier | Not applicable | No free tier, trial or self-serve signup. Sign-in requires a company Sierra deployment that already exists ('Enter your company's Sierra URL'), and every call to action is the 'Learn more' contact form. ## What it does **Writes code** · Partly — Ghostwriter turns a prompt, an SOP or a transcript into a production agent journey with workflows and guardrails; what it authors is agent configuration, not application source code. > Build or modify agents by describing how you want them to behave. Update workflows, systems integrations, guardrails, tone, and style with simple prompts. > — https://sierra.ai/product/ghostwriter · Build section, 'Prompts, not clicks' **Debugs and fixes** · Partly — Ghostwriter diagnoses its own failed simulations and implements the fix; the failure it repairs is agent behaviour, never a defect in your software. > When a simulation fails, Ghostwriter diagnoses the issue and implements the fix, so your agent keeps improving without manual debugging. > — https://sierra.ai/product/ghostwriter · Test section, 'Close the loop automatically' **Writes tests** · Partly — It generates and runs conversational test suites for the agent you build, which is testing, but not unit tests over a code repository. > Build a test suite to detect and prevent potential regressions prior to releasing new versions of your agent. > — https://sierra.ai/product/agent-studio · Simulations section, 'Regression testing' item **Ships it** · Partly — It ships agent versions rather than code: publishing to ChatGPT can run through CI/CD, but nothing deploys application software. > Make your agent available on ChatGPT with the push of a button or via CI/CD. > — https://sierra.ai/product/channels · ChatGPT section, 'Publish in one click' item **Done-for-you service** · Partly — You license software and get Sierra's own agent-development team alongside it, so delivery is a partnership rather than pure self-serve tooling. > Work with an expert agent development team that has supported hundreds of deployments — and will keep you ahead as AI evolves. Only pay for the value delivered. > — https://sierra.ai/product · 'The Sierra difference' section, 'Long-term partnership, priced by outcomes' item ## How much it does unattended **Runs autonomously** · Yes — Agents resolve end-to-end customer requests without a human in the loop, including email replies and multi-step actions in systems of record. > Autonomously respond to customer emails, reducing response times and freeing up your support team. > — https://sierra.ai/product/channels · Email section, 'Turn every email into a resolution' item **Multi-agent** · Partly — Two vendor agents hand work to each other — Explorer's findings go straight to Ghostwriter — but customer-built agents coordinating on one task is not documented publicly. > Send any recommendation directly to Ghostwriter, and it implements the improvement automatically, without any manual work on your part. > — https://sierra.ai/product/explorer · 'From insight to action' section, 'One-click handoff to Ghostwriter' item **Agent permissions** · Yes — Autonomy is configurable per workflow: you set goals and guardrails and name the steps that require human sign-off before the agent proceeds. > Define what the agent can do on its own, and where human sign-off is required. > — https://sierra.ai/product/horizon · Control section, 'Goals and guardrails' item ## Which models it runs on **Claude** · Partly — Anthropic is a named AI-services subprocessor, so Claude is in the mix, but Sierra routes models itself and never exposes a Claude selector. > Anthropic, PBC • AI services • United States > — https://trust.sierra.ai/subprocessors · Subprocessors list, Anthropic row **GPT** · Partly — OpenAI is listed as an AI-services subprocessor, so GPT models are used under the hood, chosen by Sierra's router rather than by the buyer. > OpenAI, L.L.C. • AI services • Global (localization available in United States, European Union) > — https://trust.sierra.ai/subprocessors · Subprocessors list, OpenAI row **Open models** · Partly — Sierra states it blends open-weight models into its constellation, but the buyer neither picks nor supplies them and no model names are published. > Sierra is built on a constellation of LLMs—combining frontier, open-weight, and proprietary models—so your agent can execute seamlessly and reliably. > — https://sierra.ai/product/trust-and-reliability · 'Constellation of models' section intro **Model choice** · No — Model selection belongs to Sierra: it routes each turn to what it judges optimal and swaps providers on outages, with no published customer model choice. > Sierra automatically switches between LLM providers to optimize your agent’s performance and maintain service continuity in case one provider experiences an outage. > — https://sierra.ai/product/trust-and-reliability · 'Constellation of models' section, 'Consistent reliability' item ## Where you use it **In your editor** · Partly — Agent SDK journeys are written in your own editor and software lifecycle, but Sierra ships no editor extension and the agent itself runs in customer channels. > Develop agents in your existing programming environment and software development lifecycle. > — https://sierra.ai/product/agent-sdk · Accessible development section, 'Modern developer experience' **In your pipeline** · Partly — Publishing an agent can be driven from CI/CD for the ChatGPT channel; Sierra publishes no broader pipeline or pull-request integration. > Make your agent available on ChatGPT with the push of a button or via CI/CD. > — https://sierra.ai/product/channels · ChatGPT section, 'Publish in one click' item **In a browser** · Yes — Agent Studio is a hosted web application where non-technical teams build journeys, manage knowledge and run simulations without code. > Empower teams to build and manage agents—no code required > — https://sierra.ai/product/agent-studio · Page headline _Not established: On the command line_ ## Whose machine it runs on **Self-hosted** · No — Sierra runs the platform in its own cloud on AWS, offering regional localization rather than deployment onto customer infrastructure. > Amazon Web Services, Inc. • Data storage, cloud hosting, and AI services • Global (localization available in United States, European Union, Southeast Asia, Japan, Australia) > — https://trust.sierra.ai/subprocessors · Subprocessors list, Amazon Web Services row **Open source** · No — The platform and its documentation are contractually confidential, which rules out any source-available or open-source distribution. > All Sierra Products are confidential, and you will not use or disclose them other than to evaluate the Sierra Products. > — https://docs.sierra.ai/ · Documentation sign-in gate, evaluation terms ## What it costs to run **How it meters** · Yes — Billing is per achieved outcome rather than per seat or per token, which Sierra states as its deliberate business model. > At Sierra, we've pioneered an entirely new business model - outcome-based pricing - where you pay only when the software achieves specific, valuable outcomes. > — https://sierra.ai/product · 'Outcome-based pricing' section **Free tier** · No — No free tier, trial or self-serve signup: sign-in requires a company deployment that already exists, and every call to action is a contact form. > Enter your company's Sierra URL > — https://sierra.ai/login · Sign-in form, single field prompt **API access** · Yes — A headless API is one of the published deployment surfaces; the reference is behind the docs sign-in, so endpoints, auth and limits are not public. > Because ADP is powered by Agent OS, you can build once and deploy everywhere you are — chat, phone, SMS, email, contact center conversations, or via Headless API. > — https://sierra.ai/blog/agent-data-platform · Body, paragraph introducing Agent Data Platform deployment surfaces **MCP server** · Partly — Agents are exposed over MCP for the ChatGPT Apps channel; a general MCP server other agents may query is not documented publicly. > Sierra agents are natively compatible with ChatGPT Apps via Model Context Protocol (MCP). > — https://sierra.ai/product/channels · ChatGPT section, 'Publish in one click' item **Bring your own key** · No — Sierra supplies and routes the inference itself through its own model subprocessors; no bring-your-own-key, own-model or own-cloud option is published. > Sierra will power your AI agent with the best available LLMs in the industry, so you (and your customers) are always benefiting from the latest developments. > — https://sierra.ai/product/trust-and-reliability · Constellation of models section, 'Continued innovation' ## Buying it for a team **A company can buy it** · Yes — This is sold only to organisations, with large regulated enterprises named as the customer base and no individual sign-up path. > 40% of the Fortune 50 partner with Sierra. > — https://sierra.ai/product · 'The Sierra difference' section subheading **Seat model** · No — Pricing is not seat-based: Sierra charges for delivered results, so no per-seat rate, floor or ceiling is published. > It's Sierra's outcomes-based model at scale: you pay for results, not tokens. > — https://sierra.ai/product/horizon · 'The next Horizon in agents' closing section **Admin controls** · Yes — Administrators constrain the agent through goals, guardrails, topic filters and human sign-off points defined before anything reaches customers. > Sierra has built-in filters and monitors for topics and keywords that are off-limits based on your company policies. > — https://sierra.ai/product/trust-and-reliability · 'Data governance and privacy' section, 'Industry standards' item **Audit log** · Partly — Agent decisions, tool calls and suppressions are auditable in Insights and Horizon; logging of administrative actions by staff is not documented publicly. > Understand the reasoning behind every agent action or answer—view knowledge sources, systems accessed, and more. > — https://sierra.ai/product/insights · Observability section, 'Auditing' item _Not established: Pooled budget, Single sign-on_ ## What happens to your code **Opt out of training** · Yes — Sierra states customer data is never used to train models at all, so there is no opt-out to negotiate per tier. > Your data is never used to train models, and we use industry-standard best practices to ensure its security. > — https://sierra.ai/product/agent-sdk · 'Next' section, 'Trust and reliability' card **Data residency** · Partly — Regional hosting localization is offered in the US, EU, Southeast Asia, Japan and Australia, but some AI subprocessors are US-only or global. > Global (localization available in United States, European Union, Southeast Asia, Japan, Australia) > — https://trust.sierra.ai/subprocessors · Subprocessors list, Amazon Web Services processing-location column **Getting out** · Partly — A control commits to deleting customer data on departure, yet no customer-facing bulk export path or credit-expiry rule is published. > Customer data deleted upon leaving > — https://trust.sierra.ai/controls · Controls list, 'Data and privacy' group **Certifications** · Yes — An unusually wide certification set is claimed and mirrored in the Trust Center, covering SOC 2, ISO 27001, ISO 42001, GDPR, HIPAA, PCI and FedRAMP High. > Sierra is committed to maintaining the highest compliance standards for our customers, including SOC 2, HIPAA, GDPR, PCI, FedRAMP High, CCPA, CSA STAR, ISO 27001, and ISO 42001. > — https://sierra.ai/product/trust-and-reliability · 'Security and compliance' section, 'Complete compliance' item ## Provenance Every fact above comes from the vendor. Nothing here is independently corroborated yet. ## Coverage elsewhere Pages about this product that the vendor does not control. The label states how independent each one is. | Source | Kind | Read | | --- | --- | --- | | cnbc.com | Independent source | 2026-08-22 | | tbpndigest.com | Independent source | 2026-08-22 | | techcrunch.com | Independent source | 2026-08-22 | | techcrunch.com | Independent source | 2026-08-22 | ## What changed - 2026-09-26 — Capabilities · Commercial terms · Free tier · Price - 2026-09-03 — Capabilities · Commercial terms · Free tier - 2026-08-31 — Capabilities · Commercial terms · Free tier - 2026-08-22 — Summary ## Correcting this record Anything marked "Not established" is a question we have not answered — it is not a No. If you represent Sierra, or anything here is wrong or out of date, you can supply it with a source: the operations this site accepts from an agent are listed at https://theagentsindex.com/.well-known/agents.json — that catalogue needs no key to read, and each entry states its own auth. Supplying evidence is free. Nothing that can be bought here changes what a field says, whether a gap is closed, or how this record is scored.