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Letta vs Lightning

Letta scores higher on the AgentReady, 72/100 against 57/100. They differ on 7 of the 41 signals. Which ones decides whether an agent can adopt them without a person watching.

What each one is

Letta. Letta is an AI research lab in San Francisco building machines that learn.

Lightning. Lightning AI is a platform for building, training and deploying AI models.

Where Letta is ahead

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

It also holds understand: authentication documented. Lightning misses it.

And on adopt, mcp integration available. Lightning misses it.

Finally, on operate, structured, predictable output and agent compatibility verified. Lightning misses those.

Where Lightning is ahead

Lightning passes structured api reference, and Letta does not. That is understand, whether an agent can read the docs and work out how the API behaves before calling it.

What neither does

Both fail openapi / spec quality, request examples provided, response examples provided, errors and status codes documented, no mandatory sales call, programmatic credential creation, machine-readable errors, retry behavior documented, 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. Letta leads 100 to 80. Letta misses nothing; Lightning misses clear canonical domain, mcp discoverable.

Understand. Lightning leads 46 to 38. Letta misses structured api reference, openapi / spec quality, request examples provided, response examples provided, errors and status codes documented; Lightning misses openapi / spec quality, authentication documented, request examples provided, response examples provided, errors and status codes documented.

Adopt. Letta leads 81 to 65. Letta misses no mandatory sales call, programmatic credential creation; Lightning misses no mandatory sales call, programmatic credential creation, mcp integration available.

Operate is whether an agent can run against it in production and recover when a call fails. Letta leads 67 to 35. Letta misses machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable; Lightning misses structured, predictable output, machine-readable errors, retry behavior documented, idempotency support, rate-limit behavior predictable, agent compatibility verified.

Pricing

Letta starts at $0/mo and has a free tier. Lightning starts at $4.50/hr and has a free tier.

Signal by signal

Which to pick

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

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