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

# Functions

> The one named read and computation boundary.

Functions are the only named read/computation boundary in the platform.
Everything that presents data — a dashboard panel, a Workshop block, an
assistant answer — reads through one.

## The rules that follow from that

* **A dashboard panel reads exactly one governed function.** A panel never owns
  object querying, sorting, grouping, aggregation, or row limits. If the panel
  needs a different shape, that is a different function.
* **Reads resolve at a basis.** Source-only governed reads compile to the
  temporal engine and execute at an exact basis. Reads use the latest
  transaction or an explicit historical id; they never see a half-published
  capture.
* **Results are bounded.** A function that would return an unbounded or
  unselective result is refused, not truncated silently.

## Running one

```bash theme={null}
atelier functions list
atelier functions run vendors_unbooked
```

For analytics as code, the same governed table is available in an explicit Arrow
representation without adding a second query doorway:

```bash theme={null}
atelier functions run vendors_unbooked \
  --dataset-transaction "$DATASET_TRANSACTION" \
  --arrow
```

JSON remains the inspectable command contract.

## Inference-backed functions

A function may declare one inference terminal. Its code authors ordered
messages: one leading `developer` message followed by one or more `user`
messages. There are no system, assistant, or tool messages.

* Developer instructions are literal text.
* Runtime scalar data is serialized canonically into user messages.
* `returns()` is the exact structured-output contract.
* One deterministic query result may feed the inference terminal only through
  `function.value`, which requires one complete row, one authored column, and one
  non-null scalar.

Execution evaluates query terminals first, resolves immutable media inside the
request-local source transaction, fingerprints the fully resolved typed input,
**closes that transaction**, and only then makes one synchronous provider call —
one choice, no tools, `store=false`.

It rejects refusals, truncation, tool calls, configured model-revision drift, and
schema-invalid output, and returns typed provider, request, and response
evidence.

<Warning>
  Model functions are explicitly invoked only. Dashboards and boot validation never
  spend nondeterministically.
</Warning>