fx | okengine

The complete fx surface — every call a flow can make, its signature, and the effect it records.

fx is the second argument of every do — the single door to the world. This page is the whole surface; each entry notes the effect it records, which is what feeds the Manifest, caching, and capability checks.

flow({
  do: async (input, fx) => {
    // everything below, on this one object
  },
});

Stores

Signature	Records	Returns
`fx.store(sqlDecl).select().from(t)…`	`read`	rows (`where` · `orderBy` · `limit` · `offset` chainable)
`fx.store(sqlDecl).insert(t).values(v)`	`write`	`Promise<void>`
`fx.store(sqlDecl).update(t).set(v).where(…)`	`write`	`Promise<void>`
`fx.store(sqlDecl).delete(t).where(…)`	`write`	`Promise<void>`
`fx.store(sqlDecl).findById(t, id)`	`read`	row \| undefined
`fx.store(kv).get / set(key, value, ttl?) / delete / list(prefix?)`	read / write	per op
`fx.store(files).put / get / delete / list(prefix?)`	read / write	per op
`fx.store(index).upsert / search(vector, topK?) / delete`	read / write	per op

See Store for the query-builder surface.

Signals

Signature	Records	Notes
`fx.emit(signal, payload?)`	`emit`	With the postgres driver, joins your transaction

Flows

Signature	Records	Returns / notes
`fx.call(flow, input?)`	`call`	The callee's `out` — runs through the same pipeline
`fx.step(name, fn)`	—	Durable step: replays from the journal, never re-runs
`fx.fail(code, data, opts?)`	—	Typed failure value (`opts.message` overrides)

Channel

Signature	Records	Notes
`fx.send(template, { to?, data?, via? })`	`send`	`via` orders the fallback chain; dry runs record would have fired

AI

Signature	Records	Returns
`fx.ask(prompt, input?, { via? })`	`ask`	Object validated against the prompt's `out`
`fx.run(agent, input?)`	`ask`	Agent result
`fx.stream(model, { prompt?, data? })`	`ask`	`AsyncIterable<string>` of chunks
`fx.search(embed, query, { topK? })`	`read`	Matches from the index/embed

AI calls are nondeterministic: journaling is forced on and auto-cache disabled around them.

Vault

Signature	Records	Returns / notes
`fx.vault(contract)`	`read`	Cleartext, inside this flow only — registered with the redactor at boot

Clock

Signature	Notes
`fx.clock.now()`	Epoch-ms, injectable — the only legal "now"
`fx.clock.sleep(label, duration)`	Durable sleep in `durable` flows; immediate otherwise

Durations: "200ms" · "30s" · "2m" · "1h" · "7d".

Cache

Signature	Notes
`fx.cache.get(key)`	Value or `undefined`
`fx.cache.set(key, value, ttl?)`	Optional TTL string
`fx.cache.getOrSet(key, ttl, produce)`	Read-through; writes invalidate by effect

Responses

Helper	Status	Body
`fx.json.ok(value, { meta? })`	200	`{ data, meta?, error: null }`
`fx.json.create(value)`	201	`{ data, error: null }`
`fx.json.empty()`	204	no body
`fx.json.with(data, meta)`	200	paginated envelope

Returning a plain value instead answers 200 with { data: value, error: null } — the helpers exist for status and meta control.

Logging, i18n, ids

Signature	Notes
`fx.log.debug/info/warn/error(msg, data?)`	Redacting — secrets print as `***`
`fx.t(key, params?)`	Localized message from the `i18n` config
`fx.id()`	UUID — the only legal id generator

Principals

Property	Shape
`fx.auth`	`{ userId: string \| null, scopes: Set<string>, verified?: boolean }`
`fx.operator`	`{ id: string \| null }` — Console plane
`fx.tenant`	`{ id: string \| null }` — active tenant

Learn more

Flow — why fx is the only door
Errors — what fx.fail produces
Configuration — the drivers behind these calls

fx

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