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LlamaIndex vs Vellum

Vellum scores higher on the AgentReady, 88/100 against 52/100. They differ on 15 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

LlamaIndex. LlamaIndex provides document parsing and extraction tools that turn complex documents into AI-ready context.

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

Where LlamaIndex is ahead

LlamaIndex passes 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.

Where Vellum is ahead

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

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

And on adopt, no mandatory sales call, programmatic credential creation, cli available and mcp integration available. LlamaIndex misses those.

Finally, on operate, structured, predictable output, machine-readable errors and retry behavior documented. LlamaIndex misses those.

What neither does

Both fail authentication documented, idempotency support, rate-limit behavior predictable, agent compatibility verified. 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 67. LlamaIndex misses clear canonical domain, clear product positioning, mcp discoverable; Vellum misses nothing.

Understand. Vellum leads 85 to 46. LlamaIndex misses openapi / spec quality, authentication documented, request examples provided, response examples provided, errors and status codes documented; Vellum misses authentication documented, limits / constraints documented.

Adopt is whether an agent can get a key and make its first successful call without a human in the loop. Vellum leads 100 to 60. LlamaIndex misses no mandatory sales call, programmatic credential creation, cli available, mcp integration available; Vellum misses nothing.

Operate. Vellum leads 67 to 35. LlamaIndex misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, agent compatibility verified; Vellum misses idempotency support, rate-limit behavior predictable, agent compatibility verified.

Pricing

LlamaIndex starts at $0/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: LlamaIndex and Vellum. Alternatives to each: LlamaIndex, Vellum.

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