# Architecture Decision Records (/vela/architecture/adr)



This directory holds the **Architecture Decision Records (ADRs)** for Vela™ — the durable record of *why* the library is shaped the way it is.

An ADR captures a single architectural decision: the forces that pushed on it, the choice that was made, the trade-offs accepted, and — most importantly — the **invariant** the decision creates. Invariants are the rules the rest of the codebase relies on. When you are evaluating whether a decision still holds, read the ADR and ask: *is the invariant still true, and is it still worth its cost?*

Vela™ is a new, modern charting library: a robust **core** surrounded by three independently swappable **layers** — data providers, scripting engines, and renderers. Most ADRs here exist to keep those layers genuinely independent.

> These ADRs describe the architecture as it stands today; revisit them as the design evolves.

## Conventions [#conventions]

* **Numbering**: four-digit, zero-padded, monotonically increasing (`0001`, `0002`, …). Numbers are never reused, even if an ADR is later superseded.
* **Filename**: `NNNN-short-kebab-title.md`. The slug should read as the decision, not the problem.
* **Shape**: every ADR uses the same sections — Title, Status, Context, Decision, Consequences / Trade-offs, and Invariant.
* **Status**: one of `Proposed`, `Accepted`, `Superseded by NNNN`, or `Deprecated`. A superseded ADR stays in place; it is never deleted.

## Index [#index]

| #                                                                         | Title                                                                | Status   |
| ------------------------------------------------------------------------- | -------------------------------------------------------------------- | -------- |
| [0001](/vela/architecture/adr/0001-neutral-model-as-cross-layer-currency) | Neutral model as the cross-layer currency                            | Accepted |
| [0002](/vela/architecture/adr/0002-core-owns-market-data)                 | Core owns market data                                                | Accepted |
| [0003](/vela/architecture/adr/0003-no-default-scripting-engine)           | No default scripting engine                                          | Accepted |
| [0004](/vela/architecture/adr/0004-enforce-layering-with-import-acl)      | Enforce layering with an import ACL                                  | Accepted |
| [0005](/vela/architecture/adr/0005-core-owns-user-drawings)               | Core owns user drawings                                              | Accepted |
| [0006](/vela/architecture/adr/0006-workspace-composes-charts)             | Workspace composes charts; chrome is a projection of the active cell | Accepted |