Function generate

generate<T = unknown>(opts: GenerateOptions): Operation<GenerateResult<T>>
Single-branch grammar-constrained generation as an Effection operation

Creates a fresh branch (or forks from opts.parent), prefills the prompt, generates to EOG, and prunes the branch. Uses Branch's async iterator — single-branch generation doesn't need batched commit.

When parent is provided, the prompt is prefilled as a delta (with turn separator) on a fork of the parent. This is the attention scratchpad pattern: the fork sees the parent's context, attends to the prompt content, generates a result, and is pruned — zero net KV cost.

The branch is always cleaned up via try/finally, even on error or scope cancellation.
Type Parameters
- T = unknown
Parameters
- opts: GenerateOptions
  Generation options (prompt, grammar, params, parse, parent)
Returns Operation<GenerateResult<T>>
Generated text, token count, and optionally parsed result
Example: Grammar-constrained JSON generation
```
const plan = yield* generate({
  prompt: planPrompt,
  grammar: planGrammar,
  params: { temperature: 0.3 },
  parse: output => JSON.parse(output),
});
```
Example: Attention scratchpad — fork, attend, extract, prune
```
const extracted = yield* generate({
  prompt: contentToAttend,
  grammar: extractionGrammar,
  parse: output => JSON.parse(output),
  parent: agentBranch,
});
// Fork is pruned — parent's KV unchanged
```
- Defined in agents/src/generate.ts:49