Built-in Source Catalog

This page is the dedicated reference for the current @source surface. It is intentionally conservative: it follows the compiler and runtime that ship today, not deferred RFC ideas or older examples.

Use Sources for the tutorial overview. Use this page when you need the trustworthy answer to:

• which built-in source kinds exist today,
• which positional arguments they take,
• which named options are actually supported,
• and which options are only partially wired or still intentionally limited.

This page documents the current shipped low-level source variants. Public code should prefer provider capability handles such as @source fs, @source http, @source env, and @source path when a built-in family exposes one. Direct @source provider.variant ... remains the underlying form and is still the right choice when you need variant-specific options that are not yet surfaced as handle members.

Reading the catalog

• Arguments are positional values written after the source kind.
• Options are named fields inside with { ... }.
• activeWhen, refreshOn, reloadOn, and restartOn are lifecycle/trigger options: they are part of the accepted source contract, but their behavior is planned in the compiler/runtime lifecycle machinery rather than by the provider-specific parser alone.
• “Not executed yet” means the option is in the current contract surface but the runtime still rejects or narrows it at provider startup.

Common current rules

• http.get, http.post, portal.openFile, portal.openUri, portal.screenshot, fs.read, socket.connect, and mailbox.subscribe currently expect a Signal (Result E A) output shape.
• fs.watch currently decodes to Text or to a payloadless sum such as Created | Changed | Deleted.
• window.keyDown currently decodes to Text, a payloadless key sum, or a single text-wrapping key constructor.
• dbus.signal and dbus.method currently decode to specific record shapes described below.
• Scheduler-owned recurrence work is still being tightened across the pipeline, so this page calls out where a contract option exists before the runtime fully executes it.

Unified capability families

These families now have a preferred public handle surface:

Family	Preferred public surface	Lowered implementation
File system	@source fs ... + FsSource	fs.read, fs.watch, plus handle-member tasks such as files.delete
HTTP	@source http ... + HttpSource	http.get, http.post, plus handle-member request tasks such as api.get
OpenAPI	@source api "spec.yaml" with { baseUrl: url, ... } + ApiSource	api.get, api.post, api.put, api.patch, api.delete
Database	@source db ... + DbSource	db.connect, db.live, plus handle-member database.query / database.commit tasks
Environment	@source env + EnvSource	env.get plus handle-member environment snapshots/listing
Logging / stdio	@source log, @source stdio	log/stdio handle members plus stdio.read
Randomness	@source random + RandomSource	handle-member random tasks such as entropy.bytes
Process / path / D-Bus / secret / auth / notifications	@source process, @source path, @source dbus, @source secret, @source auth, @source notifications	existing built-in providers plus handle-member host snapshots, bus.call, desktop keyring tasks, PKCE auth tasks, and desktop notification send/response streams

Incoming payloads decode directly into the annotated target type. JSON-as-text helpers are no longer part of the public external boundary.

Timers

timer.every

Form: @source timer.every interval

Option	Type	Current support
immediate	Bool	Supported. Publishes once immediately before the repeating cadence starts.
jitter	Duration	Supported. Adds a random positive offset (from 0 up to the jitter value) to each tick interval. The jitter must not exceed the base interval.
coalesce	Bool	Supported. True (default) coalesces missed ticks into a single event per sleep cycle. False fires all overdue ticks individually.
restartOn	Signal A	Supported as an explicit trigger option. Reconfigures the timer and restarts its cadence.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• The interval is the single positional argument.
• The runtime still accepts a bare integer timer argument as a legacy milliseconds path, but new documentation should prefer Duration values.

timer.after

Form: @source timer.after delay

Uses the same option surface and current limitations as timer.every, but fires once instead of repeating. restartOn re-arms the one-shot delay each time its trigger fires.

HTTP

http.get

Form: @source http.get url

Option	Type	Current support
headers	Map Text Text	Supported.
query	Map Text Text	Supported.
decode	DecodeMode	Supported through the decode pipeline.
timeout	Duration	Supported.
retry	Retry	Supported.
refreshOn	Signal B	Supported as an explicit trigger option.
refreshEvery	Duration	Supported as polling cadence input.
activeWhen	Signal Bool	Supported as a lifecycle gate.
body	A	Supported. Sends the value as the request body (text or JSON-encoded). While uncommon, RFC 9110 permits request bodies on GET.

Notes

• http.get is request-like: newer generations supersede older ones.
• Repeated requests still need an explicit wakeup such as reactive inputs, refreshOn, refreshEvery, or retry.

http.post

Form: @source http.post url

Uses the same option surface as http.get, plus:

Option	Type	Current support
body	A	Supported for http.post only.

Portals

portal.openFile

Form: @source portal.openFile config

Field / option	Type	Current support
positional config.title	Text	Supported. Dialog title. Default: "Open File".
positional config.acceptLabel	Text	Supported. Custom accept button label.
positional config.modal	Bool	Supported. Modal hint. Default: True.
positional config.multiple	Bool	Supported. Multi-select chooser.
positional config.directory	Bool	Supported. Directory picker instead of file picker.
positional config.currentFolder	Text	Supported. Suggested starting folder path.
positional config.filters	List PortalFileFilter	Supported. Serialized as glob filters for the XDG portal file chooser.
refreshOn	Signal A	Supported as an explicit trigger option.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• portal.openFile is request-like: it runs once per subscription/trigger.
• Success publishes SingleFile uri, MultipleFiles uris, or SelectionCancelled.
• Runtime failures publish PortalUnavailable, PortalPermissionDenied, or PortalDecodeFailed in the outer Err.

portal.openUri

Form: @source portal.openUri uri

Option	Type	Current support
ask	Bool	Supported. Asks the portal to prompt for an app choice.
writable	Bool	Supported. Forwards writable handoff where the backend supports it.
activationToken	Text	Supported. Forwarded to the chosen app.
refreshOn	Signal A	Supported as an explicit trigger option.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• Success publishes UriOpened uri, UriOpenCancelled, or UriOpenFailed message.
• Portal transport/protocol failures still surface through the outer Err PortalError.

portal.screenshot

Form: @source portal.screenshot

Option	Type	Current support
interactive	Bool	Supported. Requests interactive capture UI where backend supports it.
modal	Bool	Supported. Modal hint.
refreshOn	Signal A	Supported as an explicit trigger option.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• Success publishes screenshot file bytes as ScreenshotBytes Bytes after reading the portal-returned file URI.
• Cancellation publishes ScreenshotCancelled.

OpenAPI

The api family provides a typed capability handle backed by an OpenAPI 3.x spec file. Member access on the handle is validated against the spec at compile time when the spec path is a static literal.

Read operations (listPets, showPetById, etc.) lower to api.get signal providers. Write operations (createPet, deletePet, etc.) lower to api.post / api.put / api.patch / api.delete intrinsic value calls.

Generate AIVI type declarations from the spec with:

aivi openapi-gen ./spec.yaml -o types/api.aivi

api.get / api.post / api.put / api.patch / api.delete

Handle form:

@source api "./spec.yaml" with {
    baseUrl: serverUrl,
    auth: BearerToken apiToken,
    timeout: 30sec
}
signal petstore : ApiSource

Option surface (same as http.get / http.post, plus):

Option	Type	Current support
baseUrl	Text	Required. Base URL prepended to every operation path.
auth	ApiAuth	Supported. Injects Authorization or X-API-Key headers from the value.
headers	Map Text Text	Supported. Additional HTTP headers.
body	A	Supported for mutation operations.
timeout	Duration	Supported.
retry	Retry	Supported.
refreshEvery	Duration	Supported.
decode	DecodeMode	Supported through the decode pipeline.
refreshOn	Signal A	Supported as an explicit trigger signal.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• The spec path (first argument) is only used at compile time for operationId validation. It is not used at runtime.
• The final request URL is baseUrl + the operation's path from the spec.
• Auth variants: BearerToken Text, BasicAuth Text Text, ApiKey Text, ApiKeyQuery Text, OAuth2 Text.
• ApiKeyQuery injects the key as a query parameter rather than a header (not yet applied at runtime).

File system

fs.watch

Form: @source fs.watch path

Option	Type	Current support
events	List FsWatchEvent	Supported. Defaults to Created, Changed, and Deleted when omitted.
recursive	Bool	Supported. When True, watches all files in the directory tree. When False (default), watches only the specified path.

Notes

• fs.watch reports file-system events only. It does not read file contents.

fs.read

Form: @source fs.read path

Option	Type	Current support
decode	DecodeMode	Supported through the decode pipeline.
reloadOn	Signal A	Supported as an explicit trigger option.
debounce	Duration	Supported.
readOnStart	Bool	Supported. Defaults to True.

Notes

• fs.read is the snapshot-reading companion to fs.watch.
• debounce and readOnStart affect runtime reads; reloadOn remains the explicit trigger mechanism.

Streams and messaging

socket.connect

Form: @source socket.connect address

Option	Type	Current support
decode	DecodeMode	Supported through the decode pipeline.
buffer	Int	Supported.
reconnect	Bool	Supported.
heartbeat	Duration	Supported. Spawns a keepalive writer thread that periodically sends a newline to prevent idle timeouts.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• socket.connect currently supports only tcp://host:port URLs.
• It is a raw TCP line-stream surface, not a WebSocket or general framed protocol surface.

mailbox.subscribe

Form: @source mailbox.subscribe mailbox

Option	Type	Current support
decode	DecodeMode	Supported through the decode pipeline.
buffer	Int	Supported.
reconnect	Bool	Supported. When True, the subscriber retries after a disconnection.
heartbeat	Duration	Supported. Publishes periodic Unit heartbeat events at the specified interval.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• mailbox.subscribe is a process-local text bus.

Processes and host context

process.spawn

Form: @source process.spawn command or @source process.spawn command args

The second positional argument, when present, is a List Text.

Option	Type	Current support
cwd	Path	Supported.
env	Map Text Text	Supported.
stdout	StreamMode	Supported. Ignore discards output, Lines publishes text lines, Bytes publishes raw byte chunks.
stderr	StreamMode	Supported. Ignore discards output, Lines publishes text lines, Bytes publishes raw byte chunks.
restartOn	Signal A	Supported as an explicit trigger option.

Notes

• The output type must currently be a sum-shaped ProcessEvent-style signal.
• Recognized event variants are Spawned, Stdout, Stderr, Exited, and Failed.
• stdout: Lines or stdout: Bytes requires a Stdout variant in the output type, and stderr: Lines or stderr: Bytes requires a Stderr variant.

Immediate host-context sources

These built-ins publish one host-context snapshot when the source starts. They do not take options.

Kind	Positional arguments	Published shape	Current notes
process.args	none	List Text	Supported. Publishes the current process arguments.
process.cwd	none	Text	Supported. Publishes the current working directory text.
process.appDir	none	Text	Supported. Publishes the app-relative directory: the resolved entry file's parent for source-backed runs, or the extracted launch directory for packaged executables.
env.get	key	Option Text	Supported. Publishes Some value when the environment variable exists, otherwise None.
stdio.read	none	Text	Supported. Reads stdin once and publishes the text snapshot.
path.home	none	Text	Supported. Fails if HOME is missing.
path.configHome	none	Text	Supported. Uses XDG_CONFIG_HOME, or falls back to $HOME/.config.
path.dataHome	none	Text	Supported. Uses XDG_DATA_HOME, or falls back to $HOME/.local/share.
path.cacheHome	none	Text	Supported. Uses XDG_CACHE_HOME, or falls back to $HOME/.cache.
path.tempDir	none	Text	Supported. Publishes the current process temp directory text.

Database

db.connect

Form: @source db.connect config

Option	Type	Current support
pool	Int	Accepted and validated. The current runtime still opens a single SQLite connection probe per source instance; pool sizing is reserved for later provider-owned pooling work.
activeWhen	Signal Bool	Supported as a lifecycle gate.

Notes

• config must currently evaluate to either a database path Text or a record containing database: Text.
• Relative database paths are resolved against the runtime working directory before publication.
• The current runtime validates that SQLite can open the target and then publishes the normalized Connection record.
• The published Connection.database field is the normalized path the runtime actually opened.
• The intended result shape is Signal (Result DbError Connection).

db.live

Form: @source db.live query

Option	Type	Current support
refreshOn	Signal B	Supported through the existing source reconfiguration lifecycle, including pre-elaborated .changed projections.
debounce	Duration	Supported for refresh reconfiguration; activation still loads immediately.
optimistic	Bool	Supported. When True, the provider may publish the previous known-good value immediately while the query runs. Default: False.
onRollback	Signal DbError	Supported as a lifecycle option. The runtime accepts this signal reference for rollback notification when an optimistic update is reverted.
activeWhen	Signal Bool	Supported through the existing source activation lifecycle.

Notes

• The compiler now recognizes db.live as a built-in provider key.
• Runtime execution now runs the query task on a worker thread and republishes on activation or refresh.
• The intended result shape is Signal (Result DbError A).
• Successful db.commit tasks now advance matching input-backed .changed signals using the current Connection.database path plus changed table names, so db.live refreshOn paths refresh automatically after commits.
• refreshOn is the whole refresh boundary in the current slice. A users.changed projection is accepted, but it is still just an explicit trigger signal routed through that same path.
• commit() now drives TableRef.changed-style refreshes automatically when the commit plan names the changed tables and the table handle resolves to the same normalized Connection.database path.
• Invalidation is still coarse at the table level in this slice. Row-scoped watch behavior remains future work.

GTK input

window.keyDown

Form: @source window.keyDown

Option	Type	Current support
capture	Bool	Supported. When True, the event controller uses the capture propagation phase. Default: False.
repeat	Bool	Supported.
focusOnly	Bool	Supported. When False, key events are captured even when the window is not focused. Default: True.

Notes

• Delivery comes from the focused window key controller.

gtk.darkMode

Form: @source gtk.darkMode

No options. The output must decode to Bool.

Emits the current system dark-mode state (True = dark) once at startup and again each time the user changes the appearance preference in GNOME Settings. Backed by adw::StyleManager::is_dark().

Example

type Theme = Light | Dark

@source gtk.darkMode
signal rawDark : Bool

signal theme : Theme

Notes

• The source fires one initial value before the first render tick, so theme is always populated when the UI first appears.
• Uses adw::StyleManager::default(), so it reflects the system-wide GNOME preference or any app-level override set via adw::StyleManager::set_color_scheme().

clipboard.changed

Form: @source clipboard.changed

No options. The output must decode to Text.

Emits the current clipboard text once at startup and again each time the GDK clipboard content changes. Backed by gdk::Display::default().clipboard(). Non-text clipboard contents (images, files) yield an empty string.

Example

@source clipboard.changed
signal clipboardText : Text

value view =
    <Window title="Clipboard Watcher">
        <Label text={clipboardText} wrap={True} halign="Start" marginStart={12} marginEnd={12} marginTop={12} marginBottom={12} />
    </Window>

Notes

• The source fires one initial value before the first render tick, so clipboardText is always populated when the UI first appears.
• Only the latest clipboard text is kept per tick (coalescing queue); rapid clipboard changes between scheduler ticks collapse to a single update.
• Reads happen asynchronously on the GLib main thread; the signal updates on the next scheduler tick after the read completes.

window.size

Form: @source window.size

No options. The output must decode to { width: Int, height: Int }.

Emits the current window dimensions once at startup and again each time the width or height of the application's root window changes.

Example

@source window.size
signal windowDimensions : { width: Int, height: Int }

value view =
    <Window title="App">
        <Label text={"W=" + Int.toText windowDimensions.width + " H=" + Int.toText windowDimensions.height} halign="Center" valign="Center" />
    </Window>

Notes

• Fires one initial value at startup before the first render tick.
• Width and height changes from the same scheduler tick are coalesced into a single update.

window.focus

Form: @source window.focus

No options. The output must decode to Bool.

Emits True when the application window gains focus and False when it loses focus. Fires once at startup with the initial focus state.

Example

@source window.focus
signal hasFocus : Bool

value view =
    <Window title="App">
        <Label text={if hasFocus "Focused" "Unfocused"} halign="Center" valign="Center" />
    </Window>

Notes

• Backed by GtkWindow::is-active property notifications.
• Fires one initial value at startup.

D-Bus

dbus.ownName

Form: @source dbus.ownName wellKnownName

Option	Type	Current support
bus	Text	Supported. Current accepted values are "session" and "system". Defaults to the session bus.
address	Text	Supported.
flags	List BusNameFlag	Supported with AllowReplacement, ReplaceExisting, and DoNotQueue.

Notes

• The output must currently decode to Text or to a payloadless BusNameState sum with exactly Owned, Queued, and Lost.

dbus.signal

Form: @source dbus.signal path

Option	Type	Current support
bus	Text	Supported. Current accepted values are "session" and "system". Defaults to the session bus.
address	Text	Supported.
interface	Text	Supported.
member	Text	Supported.

Notes

• The output must currently be a record with fields path, interface, member, and body.
• Header fields must decode as Text.
• The body field may currently be Text or List DbusValue.
• Maybe payloads and floating-point D-Bus payloads are still outside the current runtime slice.

dbus.method

Form:

@source dbus.method destination, replyTask with { ... }

Option	Type	Current support
bus	Text	Supported. Current accepted values are "session" and "system". Defaults to the session bus.
address	Text	Supported.
path	Text	Supported.
interface	Text	Supported.
member	Text	Supported.
reply	Text	Supported. Legacy raw GLib-variant text for immediate fixed replies.
replyValues	List DbusValue	Supported. Immediate fixed reply encoded from AIVI DbusValue constructors.

Notes

• The output must currently be a record with fields destination, path, interface, member, and body.
• Header fields must decode as Text.
• The body field may currently be Text or List DbusValue.
• dbus.method currently acts as a service-side method handler: it watches incoming calls whose destination/path/interface/member match the configured filter, publishes the call record into the signal graph, and replies immediately on the wire.
• When present, the optional second source argument must be a Task that returns List DbusValue; the runtime executes it on each incoming call and sends its result as the method reply body.
• Use a comma before replyTask when it starts with an identifier or other apply-able expression, so the parser treats it as a second source argument instead of ordinary function application.
• reply and replyValues are mutually exclusive. Without either option, the runtime replies with Unit.
• A reply task argument is mutually exclusive with reply and replyValues.
• Reply tasks currently do not receive the incoming DbusCall as an explicit parameter; fully call-dependent reply closures remain future work.

dbus.emit

Form: @source dbus.emit path

Option	Type	Current support
bus	Text	Supported. Current accepted values are "session" and "system". Defaults to the session bus.
address	Text	Supported.
interface	Text	Supported.
member	Text	Supported.
body	Text	Supported. Sent as a single string argument.
bodyValues	List DbusValue	Supported. Encoded as a tuple of D-Bus arguments.
refreshOn	Signal B	Supported.
activeWhen	Signal Bool	Supported.

Notes

• The intended output shape is Signal (Result DbusError Unit).
• body and bodyValues are mutually exclusive.
• bodyValues encodes each list element as one D-Bus argument using the current DbusValue runtime slice.

bus.call

Form: @source dbus destination + bus.call path interface member body

Input piece	Type	Current support
destination	Text	Supported through the handle argument.
path	Text	Supported.
interface	Text	Supported.
member	Text	Supported.
body	List DbusValue	Supported. Encoded as a tuple of D-Bus arguments.
bus option	Text	Supported. Current accepted values are "session" and "system". Defaults to the session bus.
address option	Text	Supported.

Notes

• Return type is DbusTask (List DbusValue).
• Reply tuples decode to a List DbusValue, one element per returned D-Bus argument.
• Task failures surface as DbusError values (ServiceUnknown, NameNotOwned, NoReply, AccessDenied, InvalidArgs, DbusProtocolError).
• The reply decoder uses the current DbusValue runtime slice, so maybe payloads and floating-point payloads remain unsupported.

GNOME Online Accounts

goa.mailAccounts

Form: @source goa.mailAccounts

No options.

Notes

• The intended output shape is Signal (Result GoaError (List GoaMailAccount)).
• The runtime publishes one full mail-account snapshot at startup and republishes whenever GOA account objects are added, removed, or change relevant properties.
• Each GoaMailAccount currently includes resolved IMAP/SMTP endpoint data plus auth data from GOA (GoaMailPassword or GoaMailOAuthToken).

IMAP

imap.connect

Form: @source imap.connect accounts

Option	Type	Current support
mailbox	Text	Supported. Defaults to "INBOX".
limit	Int	Supported. Limits fetched headers per account. Defaults to 25.
refreshOn	Signal B	Supported.
activeWhen	Signal Bool	Supported.

Notes

• accounts must currently evaluate to List GoaMailAccount.
• The intended output shape is Signal (Result ImapError (List ImapSnapshot)).
• Each sync cycle selects the configured mailbox on every listed account and fetches up to limit recent message headers.

imap.idle

Form: @source imap.idle accounts

Option	Type	Current support
mailbox	Text	Supported. Defaults to "INBOX".
activeWhen	Signal Bool	Supported.

Notes

• accounts must currently evaluate to List GoaMailAccount.
• The intended output shape is Signal (Result ImapError ImapLiveEvent).
• The current runtime uses a polling fallback and emits NewMessage events when the highest UID changes. Full RFC 2177 IDLE semantics remain future work.

imap.fetchBody

Form: @source imap.fetchBody request

Option	Type	Current support
refreshOn	Signal B	Supported.
activeWhen	Signal Bool	Supported.

Notes

• request must currently evaluate to a record carrying GoaMailAccount-style connection fields plus mailbox: Text and uid: Int.
• The intended output shape is Signal (Result ImapError ImapBody).
• The runtime fetches the full raw message body and extracts best-effort plain-text and HTML bodies.

Custom source providers

Custom @source uses are supported through top-level provider qualified.name declarations.

Current declaration reality:

• provider names are qualified top-level names such as custom.feed,
• supported declaration fields are argument, option, and wakeup,
• wakeup: currently accepts timer, backoff, sourceEvent, or providerTrigger,
• argument and option schemas stay within the current closed proof surface,
• custom providers do not inherit built-in option semantics unless the custom contract declares them.

That means there is no fixed compiler-owned catalog for custom provider keys. Each custom @source some.name ... site is checked against the matching in-program provider some.name contract.