# lemma_engine v0.10.2 - Table of Contents

> Lemma rules engine for Elixir

## Pages

- [Lemma](readme.md)

## Modules

- [Lemma](Lemma.md): Lemma rules engine for Elixir.
- [Lemma.EngineError](Lemma.EngineError.md): Structured engine error as returned by NIF error paths (`load`, `show`, `run`,
`format`, …). Keys are atoms (Rustler encoding), not JSON strings.
- [Lemma.Mcp](Lemma.Mcp.md): Pure Lemma MCP tools: engine + JSON args in, catalog or tool result text out.
- [Lemma.OpenAPI](Lemma.OpenAPI.md): OpenAPI and temporal API docs helpers (`lemma_openapi` crate). Separate from core [`Lemma`] runtime.

- [Lemma.PathSegment](Lemma.PathSegment.md): One `uses` hop on a Show data or rule path.
- [Lemma.Response](Lemma.Response.md): Typed projection of the JSON map returned by `Lemma.evaluate/3`: evaluated rule
results and the resolved temporal window of the spec version actually run.
- [Lemma.RuleResult](Lemma.RuleResult.md): One rule result from `Lemma.evaluate/3`, as returned in `Lemma.Response.results`.
- [Lemma.Show](Lemma.Show.md): Typed projection of the map returned by `Lemma.show/4`: a Draft 2020-12 JSON
Schema for the spec's evaluation-data inputs, with Lemma metadata under `x-lemma-*`.
- [Lemma.ShowData](Lemma.ShowData.md): One evaluation-data input of a spec, as returned in `Lemma.Show.data`: one `properties`
entry of the Show JSON Schema document, keyed by its input key.
- [Lemma.ShowRow](Lemma.ShowRow.md): Row object schema of an instance list, as returned in `Lemma.Show.rows`: one
`$defs` entry of the Show document per row spec, referenced from a list property's
`items` `$ref`.
- [Lemma.ShowRule](Lemma.ShowRule.md): One rule in `Lemma.Show.rules` (`x-lemma-rules`: this spec's graph, local plus reachable imports).
- [Lemma.Transport](Lemma.Transport.md): Default HTTP transport for `Lemma.install/3`. Uses Req without automatic retries so
registry failures surface promptly to the install step machine.

