> ## Documentation Index
> Fetch the complete documentation index at: https://docs.summand.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Components

> The unit of analysis Summand runs. Six user-visible components in the catalog today, all stable, plus internal-only dependencies.

A **component** is a self-contained piece of analysis with typed inputs and outputs. Components are the things experiments run; they're also what the dataset's **Components** tab assigns and configures. You don't write components — they're built by Summand and exposed through a **catalog** the in-product editor reads to render forms, validate inputs, and dispatch runs.

## The catalog

Six components are visible in the experiment editor:

<CardGroup cols={2}>
  <Card title="Column stats" icon="table" href="/concepts/components/column-stats">
    Per-column distributions, missingness, cardinality, and basic numeric statistics. Runs automatically on first ingest.
  </Card>

  <Card title="Predictors (EBM)" icon="brain" href="/concepts/components/ebm">
    Fits an Explainable Boosting Machine and writes feature importance, shape functions, and pairwise interactions.
  </Card>

  <Card title="Correlation-association matrix" icon="table-cells-large" href="/concepts/components/correlation-association-matrix">
    Correlations and other measures of association for every column pair.
    <Badge color="yellow">Beta</Badge>
  </Card>

  <Card title="Forecast" icon="chart-line" href="/concepts/components/forecast">
    Time-series projection with 95% prediction intervals, using a Holt-Winters model under the hood.
  </Card>

  <Card title="Outlier report" icon="triangle-exclamation" href="/concepts/components/outlier-report">
    Identifies unusual values and anomalous rows.
    <Badge color="yellow">Beta</Badge>
  </Card>

  <Card title="Feature metadata" icon="text" href="/concepts/components/feature-metadata">
    LLM-generated, business-friendly descriptions for every dataset column. Powers chat grounding.
  </Card>

  <Card title="UMAP embedding" icon="grid-2" href="/concepts/components/umap">
    A 2-D projection of feature space for cluster visualization and "similar rows" queries.
  </Card>

  <Card title="Missing-value patterns" icon="eye-slash" href="/concepts/components/missing-value-patterns">
    Identifies patterns in the missing data.
    <Badge color="yellow">Beta</Badge>
  </Card>

  <Card title="Distribution profile" icon="chart-area" href="/concepts/components/distribution-profile">
    Per-column information about the shape of the data distribution.
    <Badge color="yellow">Beta</Badge>
  </Card>
</CardGroup>

Two other components (`ebm_model`, `forecast_model`) exist behind the scenes as **dependencies** — they hold the heavy fitted state and are consumed by the user-visible ones. You don't pick them in the editor; they auto-run when their dependent component is selected.

## Anatomy of a component

Every component declares the same metadata:

| Field             | Purpose                                                                                                                        |
| ----------------- | ------------------------------------------------------------------------------------------------------------------------------ |
| `name`            | Catalog ID (e.g. `column_stats`, `ebm_graphs`). Stable across versions.                                                        |
| `display.label`   | Human-readable name shown in the UI.                                                                                           |
| `description`     | One-sentence summary.                                                                                                          |
| `dependencies`    | Other components that must run first. The dispatcher topologically orders them.                                                |
| `inputs`          | Typed parameters the user fills in (column references, numeric thresholds, etc.).                                              |
| `compute_profile` | `LambdaProfile` for fast steps; `EcsProfile(tier)` for the heavier ones (EBM fitting, UMAP).                                   |
| `agent_config`    | What the Summand chat agent can read and filter.                                                                               |
| `display.blocks`  | How the artifact renders in the UI — tables, charts, key/value pairs. Some components ship with bespoke React viewers instead. |

When you select a component in the experiment editor, the catalog is what tells the form which inputs to render and how to validate them.

## How components run

```
Experiment fires (manual / scheduled)
   │
   ▼
trigger-semantic-layer (Lambda)
   │
   ▼
Step Functions dispatcher
   │
   ├─ ResolveComponentPlan (topological sort → waves)
   │
   ├─ For each wave (in order):
   │     └─ Distributed Map fan-out (parallel within wave)
   │           ├─ Lambda components → component-runner Lambda
   │           └─ Fargate components → ECS task
   │
   ├─ WriteManifest (consolidates results → manifest.json)
   │
   └─ UpdateSemanticLayerRecord (marks version completed)

Outputs land in:
   - S3: semantic-layers/{datasetId}/versions/{N}/{component}.json
   - DynamoDB summand-task-outputs (per-run output items)
```

Components within a wave run in parallel; waves run sequentially because of dependencies.

## Reading component outputs

Three places where outputs surface:

* **Dataset detail → Components tab.** Per-component status plus the latest artifact, rendered with either the component's declared blocks or a bespoke React viewer (for EBM, UMAP, and Feature metadata).
* **Summand chat.** The `analyze` tool resolves the latest version of any component and returns its data inline. Filtering by column or feature name is supported through each component's `agent_config`.
* **Downstream views.** Components write to S3 paths and DynamoDB items you can join against in custom SQL views.

## What's not a component

A few analyses run *outside* the component catalog:

* **Surprise finding** has its own Step Functions pipeline that runs alongside the semantic-layer dispatcher. It's not selectable in the experiment editor today — surprises surface through their own page in the product.
* **Sync / curation** (the read-from-source-and-write-to-Parquet step) is part of the connector pipeline, not the component catalog.
* **Chat itself** isn't a component — it's a separate Lambda (`claude-stream`) that *consumes* component outputs via the `analyze` tool.

## Catalog stability

The catalog is small and slow-moving. Most recent commits are bug fixes (cache improvements, edge-case handling) rather than new components. If you have a need for analysis the catalog doesn't cover, custom components are on the roadmap for Enterprise — email [enterprise@summand.com](mailto:enterprise@summand.com) and tell us what you'd build.

## Per-component details

* [**Column stats**](/concepts/components/column-stats) — what runs by default on every dataset.
* [**Predictors (EBM)**](/concepts/components/ebm) — interpretable model fitting, with shape functions and pairwise interactions.
* [**Correlation-association matrix**](/concepts/components/correlation-association-matrix) — meaasures of association between every column pair.
* [**Forecast**](/concepts/components/forecast) — time-series projection with prediction intervals.
* [**Feature metadata**](/concepts/components/feature-metadata) — LLM-generated column descriptions.
* [**UMAP embedding**](/concepts/components/umap) — 2-D projection for clustering and similarity.