orca/docs/reference/plugin-host-api.md

Orca plugin host API reference

Host API 1.4 ("pluginApi": 1). Workers call a method with await orca.host.call(name, params); panels and custom editors call the same methods through window.orca.host.call(name, params). Each method lists the surfaces allowed to call it; any other surface gets not_permitted. orca.host.has(name) answers synchronously whether this Orca offers a method on the current surface, and orca.api is { major, minor }. See Plugin authoring for the frame API.

Every call is checked against the capabilities the user approved, and params are validated before Orca runs anything: params are strict, so a field this Orca does not know is refused with invalid_params instead of being dropped. Mutations are recorded in the audit log as plugin:<publisher>.<id>.

Methods whose capability is none need no capability but still need the plugin enabled and approved. shell.openExternal and files.saveAs also need transient user activation (a click or key press in the calling frame, within a few seconds), are rate-limited, and run only in the desktop app; frames also reach them as orca.shell.openExternal(url) and orca.files.saveAs({ suggestedName, mimeType, data }), which resolves with { status: "saved" }, or { status: "cancelled" } when the person cancels the dialog. Saved files carry the OS mark for downloaded files.

Methods

Method	Capability	Surfaces	Mutation	Since	Summary
workspace.readContext	workspace:read	worker, panel, editor	no	1.0	Branch, name and terminal ids of the focused workspace, or null when none is focused.
terminal.sendText	terminal:send	worker	yes	1.0	Types text into one terminal named by id, optionally pressing Enter.
notifications.show	notifications:show	worker, panel, editor	yes	1.0	Shows a desktop notification.
storage.get	storage:own	worker, panel, editor	no	1.0	Reads a JSON value from the plugin's private store; null when absent.
storage.set	storage:own	worker, panel, editor	yes	1.0	Writes a JSON value to the plugin's private store.
storage.delete	storage:own	worker, panel, editor	yes	1.0	Removes a key from the plugin's private store.
storage.keys	storage:own	worker, panel, editor	no	1.0	Lists the keys in the plugin's private store.
secrets.get	secrets:own	worker, panel, editor	no	1.0	Reads a secret from the plugin's encrypted secrets file; null when absent.
secrets.set	secrets:own	worker, panel, editor	yes	1.0	Stores a secret in the plugin's encrypted secrets file.
secrets.delete	secrets:own	worker, panel, editor	yes	1.0	Removes a secret from the plugin's encrypted secrets file.
secrets.protection	secrets:own	worker, panel, editor	no	1.1	How secrets are protected at rest: os-keyring, or unavailable (no OS key store, or Linux basic_text), where secrets.set fails.
settings.get	settings:own	worker, panel, editor	no	1.0	Reads every setting the plugin owns.
settings.set	settings:own	worker, panel, editor	yes	1.0	Writes one setting the plugin owns.
shell.openExternal	none	panel, editor	no	1.1	Opens an http:, https: or mailto: URL in the default browser. Needs a click or key press in the frame; desktop app only. Orca asks the person before an http(s) host the plugin was not allowed; opened is false if they cancel.
files.saveAs	none	panel, editor	yes	1.1	Offers data (a string or ArrayBuffer, up to 64 MiB) in Orca's save dialog; the plugin never learns the path. Needs a click or key press in the frame; desktop app only.
plugin.request	none	panel, editor	no	1.2	Asks the plugin's own worker to run the handler it registered with orca.panels.handle(name), starting the worker if needed; resolves with what the handler returned. unknown_method when no handler has that name.
agents.list	agent:read	worker, panel, editor	no	1.2	The agents in the focused workspace: their terminal, title, agent kind and status. agent.status.changed reports each change after.
events.subscribe	none	panel, editor	no	1.2	Delivers a workspace or agent event to this panel as orca.on(event); needs the event's read capability. The frame APIs call it for you.
statusBar.update	none	worker	no	1.2	Changes one of the plugin's contributes.statusBarItems (named by id): fields given replace their current value, visible: false hides it. Desktop app only; lasts until Orca restarts, and is hidden while the plugin is disabled. A plugin with main and status bar items has its worker started when it is enabled and kept running while it stays enabled, so a worker can poll and update its items without an event or a hook.
appearance.read	appearance:write	worker	no	1.4	Reads the current desktop appearance revision for a conditional update.
appearance.apply	appearance:write	worker	yes	1.4	Publishes owned app/editor and terminal colors and selects them in the desktop. Returns publication, not renderer acknowledgement.
workspace.list	workspace:read	worker	no	1.3	Lists every workspace, Git worktrees and folders, on every host Orca reaches.
workspace.open	workspace:write	worker	yes	1.3	Shows a workspace in Orca, as clicking it in the sidebar does; a folder workspace needs the desktop app.
terminal.create	terminal:send	worker	yes	1.3	Opens a terminal in a workspace, optionally running a command, in the background.
terminal.read	terminal:read	worker	no	1.3	Reads a terminal's newest output as plain text, at most 2000 lines.
agent.launch	agent:launch	worker	yes	1.3	Starts an agent's CLI in a new terminal of a workspace, in the background, and returns as soon as it starts; a prompt is sent once the agent is ready.
editor.open	workspace:write	worker	yes	1.3	Opens a file of a workspace in an editor tab of Orca's window; desktop app only. workspace.open shows the workspace.
commands.run	workspace:write	worker	yes	1.3	Runs one of Orca's built-in actions in its window, never a plugin's replacement of it; desktop app only.

workspace.readContext

Branch, name and terminal ids of the focused workspace, or null when none is focused.

(params?: {}) => { branch: string; displayName: string; terminals: { id: string; title?: string }[] } | null

terminal.sendText

Types text into one terminal named by id, optionally pressing Enter.

(params: { terminalId: string; text: string; enter?: boolean }) => { accepted: boolean }

notifications.show

Shows a desktop notification.

(params: { title: string; body?: string }) => { delivered: boolean }

storage.get

Reads a JSON value from the plugin's private store; null when absent.

(params: { key: string }) => { value: JSON }

storage.set

Writes a JSON value to the plugin's private store.

(params: { key: string; value: JSON }) => { ok: true }

storage.delete

Removes a key from the plugin's private store.

(params: { key: string }) => { ok: true }

storage.keys

Lists the keys in the plugin's private store.

(params?: {}) => { keys: string[] }

secrets.get

Reads a secret from the plugin's encrypted secrets file; null when absent.

(params: { key: string }) => { value: string | null }

secrets.set

Stores a secret in the plugin's encrypted secrets file.

(params: { key: string; value: string }) => { ok: true }

secrets.delete

Removes a secret from the plugin's encrypted secrets file.

(params: { key: string }) => { ok: true }

secrets.protection

How secrets are protected at rest: os-keyring, or unavailable (no OS key store, or Linux basic_text), where secrets.set fails.

(params?: {}) => { status: "os-keyring" | "unavailable" }

settings.get

Reads every setting the plugin owns.

(params?: {}) => { settings: Record<string, JSON> }

settings.set

Writes one setting the plugin owns.

(params: { key: string; value: JSON }) => { ok: true }

shell.openExternal

Opens an http:, https: or mailto: URL in the default browser. Needs a click or key press in the frame; desktop app only. Orca asks the person before an http(s) host the plugin was not allowed; opened is false if they cancel.

(params: { url: string }) => { opened: boolean; reason?: "cancelled" | "consent-unavailable" }

files.saveAs

Offers data (a string or ArrayBuffer, up to 64 MiB) in Orca's save dialog; the plugin never learns the path. Needs a click or key press in the frame; desktop app only.

(params: { suggestedName?: string; mimeType?: string; data: string | ArrayBuffer }) => { status: "saved" | "cancelled" }

plugin.request

Asks the plugin's own worker to run the handler it registered with orca.panels.handle(name), starting the worker if needed; resolves with what the handler returned. unknown_method when no handler has that name.

(params: { name: string; input?: JSON; timeoutMs?: number }) => { output: JSON }

agents.list

The agents in the focused workspace: their terminal, title, agent kind and status. agent.status.changed reports each change after.

(params?: {}) => { agents: { terminalId: string | null; title: string | null; agent: string | null; state: "working" | "blocked" | "waiting" | "done"; stateStartedAt: number }[] }

events.subscribe

Delivers a workspace or agent event to this panel as orca.on(event); needs the event's read capability. The frame APIs call it for you.

(params: { event: "workspace.created" | "workspace.removed" | "agent.status.changed" | "workspace.changed" }) => { ok: true }

statusBar.update

Changes one of the plugin's contributes.statusBarItems (named by id): fields given replace their current value, visible: false hides it. Desktop app only; lasts until Orca restarts, and is hidden while the plugin is disabled. A plugin with main and status bar items has its worker started when it is enabled and kept running while it stays enabled, so a worker can poll and update its items without an event or a hook.

(params: { id: string; text?: string; icon?: "activity" | "bar-chart-3" | "bell" | "blocks" | "book" | "bot" | "bug" | "calendar" | "cloud" | "code" | "database" | "file-text" | "flag" | "folder" | "gauge" | "globe" | "hammer" | "layers" | "lightbulb" | "package" | "plug" | "puzzle" | "rocket" | "star" | "terminal" | "wrench" | "zap" | "add" | "remove" | "delete" | "edit" | "refresh" | "search" | "settings" | "check" | "close" | "info" | "warning" | "error" | "open-external" | "copy" | "download" | "upload" | "play" | "pause" | "stop" | "more" | "expand" | "collapse" | "next" | "filter" | "branch" | "file" | "agent" | "link"; tone?: "neutral" | "accent" | "success" | "warning" | "danger"; tooltip?: string; visible?: boolean }) => { ok: true }

appearance.read

Reads the current desktop appearance revision for a conditional update.

(params?: {}) => { revision: string }

appearance.apply

Publishes owned app/editor and terminal colors and selects them in the desktop. Returns publication, not renderer acknowledgement.

(params: { expectedRevision: string; app: string; terminal: string }) => { revision: string; themeId: string; mode: "dark" | "light"; delivery: "published" }

workspace.list

Lists every workspace, Git worktrees and folders, on every host Orca reaches.

(params?: {}) => { workspaces: { id: string; kind: "worktree" | "folder"; name: string; path: string; branch: string | null; hostId: string | null }[]; truncated: boolean }

workspace.open

Shows a workspace in Orca, as clicking it in the sidebar does; a folder workspace needs the desktop app.

(params: { workspaceId: string }) => { opened: true }

terminal.create

Opens a terminal in a workspace, optionally running a command, in the background.

(params: { workspaceId: string; title?: string; command?: string }) => { terminalId: string }

terminal.read

Reads a terminal's newest output as plain text, at most 2000 lines.

(params: { terminalId: string; maxLines?: number }) => { lines: string[]; truncated: boolean }

agent.launch

Starts an agent's CLI in a new terminal of a workspace, in the background, and returns as soon as it starts; a prompt is sent once the agent is ready.

(params: { workspaceId: string; agent: string; prompt?: string }) => { terminalId: string }

editor.open

Opens a file of a workspace in an editor tab of Orca's window; desktop app only. workspace.open shows the workspace.

(params: { workspaceId: string; path: string }) => { opened: true }

commands.run

Runs one of Orca's built-in actions in its window, never a plugin's replacement of it; desktop app only.

(params: { action: "worktree.history.back" | "worktree.history.forward" | "sidebar.left.toggle" | "sidebar.sleepingWorkspaces.toggle" | "floatingWorkspace.maximize" | "tab.rename" | "workspace.rename" | "workspace.openBoard" | "view.tasks" | "sidebar.right.toggle" | "sidebar.explorer.toggle" | "sidebar.search.toggle" | "sidebar.sourceControl.toggle" | "sidebar.checks.toggle" | "sidebar.ports.toggle" }) => { ran: true }

Events

A worker receives the events its manifest lists in contributes.events through orca.events.on(event, handler), which returns { dispose() }. Each needs main, the trusted-worker profile and its domain's capability (workspace:read or agent:read). orca plugin types writes the payloads as PluginEvents in orca/host.

Event	Payload	Summary
workspace.created	{ workspaceId: string; kind: "worktree" | "folder"; path: string; branch: string }	A worktree workspace was created.
workspace.removed	{ workspaceId: string; kind: "worktree" | "folder"; path: string }	A worktree workspace was removed.
agent.status.changed	{ workspaceId: string | null; paneKey: string; terminalId?: string; title?: string; state: "working" | "blocked" | "waiting" | "done"; receivedAt: number; mainAgent?: { state: "working" | "blocked" | "waiting" | "done"; outcome?: "success" | "failure" | "cancellation" | "superseded" | "interruption" | "unconfirmed"; stateStartedAt: number } }	An agent in a terminal pane changed status; workspaceId is null when Orca cannot tie the pane to a workspace, and terminalId names its terminal when Orca lists it.
workspace.changed	{ context: { branch: string; displayName: string; terminals: { id: string; title?: string }[] } | null }	The focused workspace changed, or its terminals were opened, closed or renamed; context is what workspace.readContext now answers. Each new subscriber first gets the current context.

Hooks

A worker changes or stops what Orca is about to do with orca.hooks.on(hook, (event, next) => ...), which returns { dispose() }. Each hook must be listed in contributes.hooks (main and the trusted-worker profile; no capability). Return next(event) to go on, with the fields the hook allows changed; return a result such as { deny: reason } to stop; return nothing to pass. Plugins run one after another (installed plugins by key, then development folders), then Orca acts on what is left. Orca starts the workers of plugins that list hooks (or status bar items) as soon as they are enabled and keeps them running until they are disabled. A handler that takes longer than 2 s, a worker that does not start within the worker ready timeout, a throw, a crash or a disabled plugin counts as having passed, and orca plugin logs shows the hook, the plugin and how long it took. A guard that must fail closed sets "onError": "deny" on its contributes.hooks entry; then those failures refuse the action, naming the plugin. Decide before any other awaited call: an awaited host call ahead of your { deny } can fail or time out and let the action through.

Hooks run in the workers of the Orca that handles the request, before it acts: for an SSH or WSL terminal or workspace, that is the desktop, before the work is sent to its host. A paired client reaching a remote Orca server is decided by that server's plugins. orca plugin types writes the events as PluginHooks in orca/host; orca/testing mountWorker(...).hooks.fire(hook, event) returns what the chain decided.

Hook	Event	Stop result	next may change	Summary
terminal.send	{ terminalId: string; text: string; enter: boolean; inputKind: "driving" | "orchestration" | "launch" }	{ deny: string }	text, enter	Text Orca, the CLI or a plugin is about to send to a terminal. A person typing (on the desktop, a phone or a paired client) is never hooked, and prompts Orca submits to an agent take agent.prompt.before instead. Writes to one terminal stay in order while a hook decides. Rewrite text or enter with next, or return { deny } to refuse the send.
workspace.create.before	{ kind: "worktree" | "folder"; projectId: string; name: string; branch?: string; base?: string }	{ deny: string }	name, branch, base	A worktree or folder workspace is about to be created. Change name, branch or base with next, or return { deny } to refuse it.
workspace.create.after	{ workspaceId: string; kind: "worktree" | "folder"; path: string; branch: string }	none	nothing	A worktree or folder workspace was created. Observe only: Orca does not wait for it, and results are ignored.
agent.launch.before	{ agent: string; workspaceId: string | null; workspaceKind: "worktree" | "folder" | null; terminalId?: string; command: string; env: Record<string, string> }	{ deny: string }	command, env	Orca is about to start an agent CLI in a terminal, from any launcher (new tab, workspace create, CLI, automation, orchestration). Change command or add env with next, or return { deny } to refuse the launch. Restores of saved sessions are not hooked.
agent.prompt.before	{ agent: string | null; terminalId: string; prompt: string; inputKind: "driving" | "orchestration" | "launch" }	{ deny: string }	prompt	Orca is about to submit a prompt to an agent in a terminal: a launch prompt, an orchestration dispatch, an issue or task prompt, or orca terminal send to an agent. A prompt a person submits is never hooked, and writes to one terminal stay in order while it decides. Rewrite prompt with next, or return { deny } to refuse it.
agent.tool.before	{ agent: string; workspaceId: string | null; terminalId?: string; tool: string; input: JSON; callId?: string }	{ deny: string }	input	An agent in an Orca terminal is about to run a tool. Claude Code waits for the answer: return { deny } to refuse the call (the agent sees the reason) or change input with next; the person is still asked as usual. Other agents only report the call, so their results are ignored. Agents on SSH or WSL hosts are not hooked yet.
agent.tool.after	{ agent: string; workspaceId: string | null; terminalId?: string; tool: string; input: JSON; callId?: string; output?: JSON }	none	nothing	An agent in an Orca terminal finished a tool call (successfully or not). Observe only: Orca does not wait for it.
editor.save.before	{ workspaceId: string | null; path: string; languageId?: string; text: string }	{ deny: string }	text	The person is about to save a text file from an Orca editor tab (an explicit save, not autosave). Change text with next (format on save) or return { deny } to refuse the save, which shows your reason. Edits made while the hook ran stay unsaved.

Errors

A failed call rejects with an Error carrying code, message, retryable and, for rate_limited, retryAfterMs. Treat a code not listed here as action_failed:

• invalid_request: the call itself is malformed.
• invalid_params: params do not match the method, including a field this Orca does not know; the message names it.
• unknown_method: the method does not exist in this Orca.
• capability_denied: the manifest does not declare the capability.
• consent_required: the plugin is disabled or the user has not approved this version.
• not_permitted: the method or document is not available here, e.g. a worker-only method from a panel.
• rate_limited: calls arrive faster than the budget; retryAfterMs says when to try again.
• unavailable: the service behind the method is not running yet.
• action_failed: the method ran and failed.
• cancelled: the caller aborted the call through its signal.
• timeout: Orca gave up waiting.
• conflict: the call was made against a stale version, e.g. an editor edit after an outside change.
• too_large: the message is larger than Orca accepts.

Stability and deprecation

Plugins are in Alpha: the manifest v2 format and catalog format are stable contracts; items listed as experimental in Plugin authoring may change.

• Host API 1 is frozen. Within pluginApi 1, methods, params and results only grow: a new method or a new optional param arrives with a higher Since minor, and nothing listed here is removed, renamed or narrowed.
• Deprecation. A method to be retired is marked deprecated in this table and keeps working for the rest of the major.
• New majors. A breaking change ships as a new pluginApi major beside the old one. Orca refuses a manifest whose pluginApi names a major it does not implement, with "update Orca", instead of loading it against the wrong API.
• Detect, do not assume. Check orca.host.has(name) or orca.api.minor before calling a method newer than the oldest Orca you support; a call that slips through fails with unknown_method.