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Helicone vs Vellum

Vellum scores higher on the AgentReady, 88/100 against 63/100. They differ on 17 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

Helicone. Helicone is an AI observability platform that helps developers build reliable AI apps by routing, debugging, and analyzing their applications.

Vellum. A personal AI assistant that lives in the secure Vellum Cloud, has its own identity, and actually does things in the world.

Where Helicone is ahead

Helicone passes authentication documented and limits / constraints documented, and Vellum does not. That is understand, whether an agent can read the docs and work out how the API behaves before calling it.

It also holds operate: agent compatibility verified. Vellum misses it.

Where Vellum is ahead

Vellum passes clear canonical domain, and Helicone does not. That is discover, whether an agent can find the product at all without being told it exists.

It also holds understand: structured api reference, openapi / spec quality, request examples provided, response examples provided and errors and status codes documented. Helicone misses those.

And on adopt, no mandatory sales call, agent-compatible signup flow, programmatic credential creation, fast time to first request, copyable quickstart and cli available. Helicone misses those.

Finally, on operate, machine-readable errors and retry behavior documented. Helicone misses those.

What neither does

Both fail idempotency support, rate-limit behavior predictable. If your agent needs any of those, you will be building it yourself either way.

Score, pillar by pillar

The AgentReady splits into four pillars, scored separately, because a product can be easy to find and still impossible to adopt.

Discover. Vellum leads 100 to 93. Helicone misses clear canonical domain; Vellum misses nothing.

Understand is whether an agent can read the docs and work out how the API behaves before calling it. Vellum leads 85 to 38. Helicone misses structured api reference, openapi / spec quality, request examples provided, response examples provided, errors and status codes documented; Vellum misses authentication documented, limits / constraints documented.

Adopt. Vellum leads 100 to 55. Helicone misses no mandatory sales call, agent-compatible signup flow, programmatic credential creation, fast time to first request, copyable quickstart, cli available; Vellum misses nothing.

Operate. Vellum leads 67 to 65. Helicone misses machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable; Vellum misses idempotency support, rate-limit behavior predictable, agent compatibility verified.

Pricing

Helicone starts at $79/mo and has a free tier. Vellum starts at $30/mo and has a free tier.

Signal by signal

Which to pick

Vellum clears more of the signals an agent needs, so it is the safer default for unattended use. Full profiles: Helicone and Vellum. Alternatives to each: Helicone, Vellum.

An agent can fetch this as data: POST /v1/compare {"slugs": ["helicone", "vellum"]}