Docs

CompletionKit ships two ways: a source-available Rails engine you self-host, and CompletionKit Cloud — the hosted version with a free tier.

Engine (self-hosted)

• README & install guide — getting the engine mounted in your Rails app
• RubyGems — version history and dependencies
• License — Business Source License 1.1, converts to GPL-3 after three years

Cloud (hosted)

• Pricing & plans
• API reference — REST endpoints, parameters, and copy-paste examples (in-app under Settings → API, wired to your own bearer keys)
• MCP server — each organization exposes an MCP endpoint for driving prompts, runs, and datasets from an LLM agent (see the API reference)

Concepts

Prompt — a versioned template + model. Each published version has a stable URL your app calls to fetch it.

Dataset — a CSV of test inputs. Runs evaluate a prompt against a dataset.

Run — one execution of a prompt across a dataset, producing responses. Optionally scored by a judge model against your metrics.

Metric — a scoring criterion (tone, accuracy, format compliance, …) with a 1–5 rubric the judge model applies to each response.

Changelog

See what's shipped.