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# Decagon vs Sierra Comes Down to Control, Not Capability

Decagon and Sierra look different in the demo. Here's the pricing and control criteria that actually predict which one fits your team.

Last updated: September 24, 2026

![Peter Isaacs](https://www.voiceflow.com/images/contributors/peter.webp)

by **[Peter Isaacs](https://www.voiceflow.com/contributors/peter)**

Senior Prompt Engineer at Voiceflow

6 min read time. Summarize with:

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![Decagon vs Sierra Comes Down to Control, Not Capability](https://www.voiceflow.com/images/decagon-vs-sierra-hero.webp)

Key takeaways

- Decagon and Sierra are the same kind of vendor: score both on pricing transparency, model control, and log access, not feature lists.

- Get a written definition of 'resolution' in the contract before you sign with either vendor, not just a percentage on a slide.

- Run a four to six week pilot on a fixed slice of real volume, scored against your own resolution definition, before you commit.

Decagon and Sierra get compared like two different products because their marketing works hard to sound like two different products. Strip away the demo scripts and the case study logos, and they're the same kind of animal: fully managed AI customer service agents, sold as an outcome rather than a platform, priced against a resolution metric each vendor defines and grades on its own terms. If you're trying to choose between them on capability alone, you're optimizing the wrong variable. The question that actually predicts which one serves your organization isn't "which agent sounds smarter in the sales call." It's "which vendor will let me verify and control what I'm paying for."

## What Decagon and Sierra Actually Sell

Both companies sell the same basic promise: an AI agent that resolves customer conversations end to end, with the vendor handling model selection, conversation design, and ongoing tuning behind the scenes. Neither positions itself as infrastructure you operate. Both position themselves as an outcome you buy, closer to an outsourced service relationship wrapped in an AI product than a platform your team configures and owns.

That framing shows up in how both companies talk about themselves in market: agents "proven" to outperform human reps, autonomous resolution rates presented as the headline metric, and a pitch that leads with "zero engineering effort required." That's a reasonable offer for a team with no appetite to build or maintain conversational AI in-house. It's also an offer that, by design, asks the buyer to trust the vendor's own account of how well the product is working, because the vendor is the one running it.

## Where the Two Platforms Genuinely Differ

The real differences between Decagon and Sierra live below the marketing layer, in questions a feature comparison pulled from either homepage won't answer honestly: which channels the agent actually runs in production versus in the demo, how deep the integration goes into your existing ticketing and CRM stack, which industries the vendor has real deployment depth in rather than showcase logos, and whether the underlying model can be swapped if pricing or performance shifts later.

None of that is something a buyer should take on faith, including from this post. It's something you settle by asking both vendors for the same evidence and comparing how they respond, not just what they claim.

DimensionWhy it mattersWhat counts as a real answer

Channel depthMarketing lists channels; production maturity varies by channelA live customer reference in the channel you need, not a roadmap slide

Model flexibilityLocked to one model means locked to one pricing curve and one failure modeA named answer on whether you can swap or run multiple models

Integration depth"Integrates with Zendesk" and "reads and writes to Zendesk in real time" are different claimsA technical walkthrough, not a logo on a partner page

Vertical maturityCase study logos aren't deployment scaleA reference customer comparable in size and complexity to yours

If a vendor can't produce that evidence quickly, treat the delay as data.

Get started

See how leading teams design, test, and deploy AI agents at scale.

## The Pricing Question Neither Vendor Answers Upfront

Resolution-based pricing sounds like alignment: you pay for outcomes, not seats or messages. In practice, it moves a critical definition out of your hands. "Resolution" isn't a standardized industry metric. Each vendor defines what counts as resolved, and each vendor grades its own agent against that definition. That's the structure common across managed AI customer service platforms broadly, Decagon and Sierra included.

The problem isn't that outcome-based pricing is dishonest. It's that a vendor grading its own homework has a structural incentive to protect margin, which can mean narrowing what qualifies as a resolution, routing harder conversations away from the metric, or defaulting to cheaper models where the contract doesn't require otherwise. None of that requires bad faith. It only requires an incentive that isn't shared with the buyer.

The fix isn't avoiding resolution-based pricing outright. It's insisting on a written, auditable definition of resolution before signature: what counts, what doesn't, how it's measured, and who can see the underlying conversation logs, not just a dashboard summary, if a dispute comes up later. If a vendor's answer to that request is a percentage on a slide, that isn't a definition.

## The Evaluation Criteria That Actually Predict Fit

Once the pricing question is settled, the comparison that predicts whether Decagon, Sierra, or something else fits your organization comes down to five criteria. They apply whether or not either vendor's name ever appears in your RFP.

CriterionQuestion to askRed flag

Pricing transparencyIs "resolution" defined in the contract, not just the pitch?Vendor won't put a definition in writing

Model and capability controlCan you see or influence which model handles a given conversation?Model choice is entirely opaque to you

Observability into gradingCan you audit the logs behind the resolution rate you're billed on?Only a summary dashboard, no trace-level access

Integration depthDoes the agent read and write to your existing systems in real time?Integration is a one-way webhook or a manual export

Exit and lock-in costWhat does migrating away cost in data, config, and time?No documented export path for your conversation data or logic

None of these criteria require you to distrust either company. They require you to price in the cost of trusting them less than the sales deck asks you to. A vendor that answers all five plainly is a safer bet regardless of which logo is on the contract. One that answers none of them plainly is a bet on goodwill, not on the product.

## How to Run Your Own Decagon vs Sierra Bake-Off

If you're deep enough into a Decagon or Sierra evaluation to be reading a comparison post, skip the generic RFP template and run a structured, time-boxed test instead.

Ask both vendors for the same three things: a written resolution definition, a reference customer at your scale and in your industry, and read access to trace-level logs for a pilot cohort of conversations, not just the dashboard. Give each vendor two weeks to produce all three. How fast and how completely they answer tells you more about how they'll treat you post-signature than any demo will.

Run the pilot against a fixed, small slice of real volume, a single queue or channel, for a fixed window of four to six weeks. Lock the resolution definition before the pilot starts, not after the results come in. Score it against your own definition of success, not the vendor's dashboard number.

That last comparison is where a different kind of platform enters the conversation. Something like [Voiceflow](https://www.voiceflow.com/platform) isn't a third managed-agent vendor competing on the same self-graded resolution claim. It's built for teams that want the control this whole evaluation is actually about: visibility into every model call, ownership of the evaluation logic, and pricing tied to usage rather than an outcome the vendor defines. If the criteria table above is the real decision in front of you, it's worth [seeing what that kind of evaluation looks like](https://www.voiceflow.com/demo) before you sign a resolution-based contract with either Decagon or Sierra.

## Frequently asked questions

**Is Decagon or Sierra better?**

Neither is categorically better. Both are fully managed AI customer service agents priced against a resolution metric each vendor defines and grades itself. Which one fits your team depends on how transparently each answers questions about pricing, model flexibility, integration depth, and log access, not on which demo sounds smarter.

**What's the difference between Decagon and Sierra?**

The marketing differs more than the underlying model. Both sell outcome-based, fully managed agents rather than a platform you configure and own. The real differences show up below the marketing layer, in channel depth, model flexibility, integration depth, and vertical deployment maturity, and those answers vary by customer, not by vendor tagline.

**How does Decagon and Sierra pricing work?**

Both typically price against a resolution metric, which sounds like paying for outcomes rather than seats. In practice, each vendor defines what counts as a resolution and grades its own agent against that definition, which moves a critical decision out of the buyer's hands unless it's written into the contract.

**What should I ask Decagon or Sierra before signing a contract?**

Ask for a written, auditable definition of resolution, a reference customer at your scale and industry, and read access to trace-level conversation logs, not just a summary dashboard. Give both vendors the same two-week window to produce all three, and treat a slow or incomplete answer as data.

**How do I run a fair evaluation between Decagon and Sierra?**

Lock a resolution definition before a pilot starts, run it against a fixed, small slice of real volume for four to six weeks, and score the results against your own definition of success rather than either vendor's dashboard number.

Last updated: September 24, 2026

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