# Diff

Splits prose into words, keeping the whitespace and punctuation between them.

- Registry name: `diff` (`@candor/diff`)
- Tier: Pro. Installing it needs a Pro, Premium or Team licence key: the person runs `npx candor-ui key <key>` themselves; never ask for the key in chat or write it to a file.
- Docs: https://candor.themethodic.com/docs/diff

## Install

```bash
npx candor-ui add diff
```

Run `npx candor-ui@latest init` once first (https://candor.themethodic.com/get-started.md). Without the CLI: `npx shadcn@latest add @candor/diff`.

## Functions

### tokenizeWords

```ts
tokenizeWords(s: string)
```

Splits prose into words, keeping the whitespace and punctuation between them.

### diffTokens

```ts
diffTokens(a: string[], b: string[])
```

A token-level diff (longest common subsequence). Adjacent ops of the same kind are merged. Falls back to one delete and one insert for very large inputs rather than spending quadratic time.

## Types

### DiffOp

```ts
{ op: "eq" | "del" | "ins"; text: string }
```

## Rules for using Candor UI

- Components take plain typed data. Never pass model output as HTML or render it as a link; messages are typed blocks.
- A control that can't be used says why: wrap it in `<Locked reason="…">`, don't just disable it.
- Don't show a value you don't have: leave it out (it renders as —) rather than guess. An estimate is labelled as one.
- Nothing is pre-selected in a decision a person makes, and the agent is named from your app's data, never from model output.
- Your app's words go in `LocaleProvider` (fixed strings) and `TermsProvider` (nouns); entity kinds and agent roles in `EntityKindsProvider` and `AgentRolesProvider`.