feat(computer): SSH computer selection + status + workspace default (handoff #2)

Mirrors the cwd/workspace UI for the SSH-computer feature:

- New feature library src/features/computer/:
  - logic/view-model.ts (pure): viewComputer/viewComputerStatus/viewTestResult/
    summarizeComputers/formatHost/knownHostLabel + state->badge for the 4
    ComputerStatusResponse states + SaveComputer/LoadComputerStatus/
    TestComputer/LoadComputers ports. 20 view-model tests.
  - ui/ComputerField.svelte: per-conversation selector (dropdown +
    connection-status badge + Test-connection, polling the selected alias).
  - ui/ComputerSelect.svelte: reusable Local/computers dropdown, shared with
    the workspace default-computer control.
- AppStore: computerId state + refreshComputer (at every focus site, parallel
  to refreshCwd) + setComputer (PUT /conversations/:id/computer, null=clear) +
  global computers catalog (GET /computers on boot, like models) +
  computerStatus(alias) + testComputer(alias). chat.send UNCHANGED (resolved
  server-side like cwd).
- App.svelte: ComputerField in the Model sidebar view next to CwdField; adapted
  ports wrap the store.
- workspaces: setDefaultComputer on WorkspaceHttp+WorkspaceStore
  (PUT /workspaces/:id/default-computer); default-computer selector in
  WorkspaceCard (reuses ComputerSelect); router passes store.computers through.
- Re-mirrored .dispatch/transport-contract.reference.md (Computers section +
  ChatRequest.computerId); updated .dispatch/wire.reference.md (Computer/
  ComputerEntry/defaultComputerId + the provider-retry divergence note from
  handoff #1); GLOSSARY + backend-handoff.md (handoff #2, §2e).

Transparency invariant: the computer is USER-facing only (a tool-execution
target, never part of the model prompt); the agent never sees it.

Verify: 795/795 tests green; biome clean; vite build succeeds; 0 typecheck
errors from the computer feature. (11 pre-existing svelte-check errors remain
from the open §2d provider-retry divergence — backend feature/ssh-support
still lacks TurnProviderRetryEvent; not from this feature.)

11 files changed, 712 insertions, 9 deletions

diff --git a/src/features/computer/index.ts b/src/features/computer/index.ts
new file mode 100644
index 0000000..656f6c2
--- /dev/null
+++ b/src/features/computer/index.ts
@@ -0,0 +1,31 @@
+export type {
+	Badge,
+	ComputerListResult,
+	ComputerSaveResult,
+	ComputerStatusResult,
+	ComputerStatusView,
+	ComputerView,
+	LoadComputerStatus,
+	LoadComputers,
+	SaveComputer,
+	TestComputer,
+	TestComputerResult,
+	TestResultView,
+} from "./logic/view-model";
+export {
+	formatHost,
+	knownHostLabel,
+	summarizeComputers,
+	viewComputer,
+	viewComputerStatus,
+	viewComputers,
+	viewTestResult,
+} from "./logic/view-model";
+export { default as ComputerField } from "./ui/ComputerField.svelte";
+export { default as ComputerSelect } from "./ui/ComputerSelect.svelte";
+
+/** Public module manifest — aggregated by the shell's "Loaded Modules" view. */
+export const manifest = {
+	name: "computer",
+	description: "Per-conversation / per-workspace SSH computer selection + status",
+} as const;
diff --git a/src/features/computer/logic/view-model.test.ts b/src/features/computer/logic/view-model.test.ts
new file mode 100644
index 0000000..d9b7f74
--- /dev/null
+++ b/src/features/computer/logic/view-model.test.ts
@@ -0,0 +1,167 @@
+import type { ComputerStatusResponse, TestComputerResponse } from "@dispatch/transport-contract";
+import type { ComputerEntry } from "@dispatch/wire";
+import { describe, expect, it } from "vitest";
+import {
+	formatHost,
+	knownHostLabel,
+	summarizeComputers,
+	viewComputer,
+	viewComputerStatus,
+	viewComputers,
+	viewTestResult,
+} from "./view-model";
+
+function computer(overrides: Partial<ComputerEntry> = {}): ComputerEntry {
+	return {
+		alias: "buildbox",
+		hostName: "10.0.0.5",
+		port: 22,
+		user: "deploy",
+		identityFile: "/home/deploy/.ssh/id_ed25519",
+		knownHost: true,
+		usageCount: 0,
+		...overrides,
+	};
+}
+
+describe("formatHost", () => {
+	it("is user@host with no port when port is the SSH default (22)", () => {
+		expect(formatHost(computer({ port: 22 }))).toBe("[email protected]");
+	});
+
+	it("appends a non-default port", () => {
+		expect(formatHost(computer({ port: 2222 }))).toBe("[email protected]:2222");
+	});
+
+	it("falls back to the alias when hostName is empty", () => {
+		expect(formatHost(computer({ hostName: "" }))).toBe("deploy@buildbox");
+	});
+});
+
+describe("knownHostLabel", () => {
+	it("is 'known host' when known", () => {
+		expect(knownHostLabel(true)).toBe("known host");
+	});
+
+	it("is 'new host' when not known", () => {
+		expect(knownHostLabel(false)).toBe("new host");
+	});
+});
+
+describe("viewComputer", () => {
+	it("projects alias + hostSummary + identity + known-host label", () => {
+		const v = viewComputer(computer());
+		expect(v.alias).toBe("buildbox");
+		expect(v.hostSummary).toBe("[email protected]");
+		expect(v.identityFile).toBe("/home/deploy/.ssh/id_ed25519");
+		expect(v.knownHostLabel).toBe("known host");
+		expect(v.knownHost).toBe(true);
+	});
+
+	it("preserves a null identityFile (default key)", () => {
+		const v = viewComputer(computer({ identityFile: null }));
+		expect(v.identityFile).toBeNull();
+	});
+});
+
+describe("viewComputers", () => {
+	it("maps each entry (and drops usageCount from the view)", () => {
+		const views = viewComputers([
+			computer({ alias: "a", usageCount: 3 }),
+			computer({ alias: "b", hostName: "b.local", usageCount: 0 }),
+		]);
+		expect(views).toHaveLength(2);
+		expect(views.at(0)?.alias).toBe("a");
+		expect(views.at(1)?.hostSummary).toBe("[email protected]");
+	});
+});
+
+describe("summarizeComputers", () => {
+	it("is 'No computers discovered' for an empty list", () => {
+		expect(summarizeComputers([])).toBe("No computers discovered");
+	});
+
+	it("is singular for one computer", () => {
+		expect(summarizeComputers([computer()])).toBe("1 computer");
+	});
+
+	it("is plural for many", () => {
+		expect(summarizeComputers([computer(), computer(), computer()])).toBe("3 computers");
+	});
+});
+
+describe("viewComputerStatus", () => {
+	function status(
+		state: ComputerStatusResponse["state"],
+		overrides: Partial<ComputerStatusResponse> = {},
+	): ComputerStatusResponse {
+		return { alias: "buildbox", state, knownHost: true, ...overrides };
+	}
+
+	it("connected → success badge, not busy, no error", () => {
+		const v = viewComputerStatus(status("connected"));
+		expect(v.statusLabel).toBe("Connected");
+		expect(v.badge).toBe("success");
+		expect(v.busy).toBe(false);
+		expect(v.error).toBeNull();
+	});
+
+	it("connecting → warning badge + busy (spinner), no error", () => {
+		const v = viewComputerStatus(status("connecting"));
+		expect(v.statusLabel).toBe("Connecting…");
+		expect(v.badge).toBe("warning");
+		expect(v.busy).toBe(true);
+		expect(v.error).toBeNull();
+	});
+
+	it("disconnected → neutral badge, NOT busy (a stable idle state)", () => {
+		const v = viewComputerStatus(status("disconnected"));
+		expect(v.statusLabel).toBe("Disconnected");
+		expect(v.badge).toBe("neutral");
+		expect(v.busy).toBe(false);
+		expect(v.error).toBeNull();
+	});
+
+	it("error → error badge, not busy, surfaces the reason", () => {
+		const v = viewComputerStatus(status("error", { error: "auth refused" }));
+		expect(v.statusLabel).toBe("Error");
+		expect(v.badge).toBe("error");
+		expect(v.busy).toBe(false);
+		expect(v.error).toBe("auth refused");
+	});
+
+	it("error falls back to a default reason when the backend omits one", () => {
+		const v = viewComputerStatus(status("error"));
+		expect(v.error).toBe("Connection failed");
+	});
+
+	it("carries the knownHost flag through", () => {
+		const v = viewComputerStatus(status("connected", { knownHost: false }));
+		expect(v.knownHost).toBe(false);
+	});
+});
+
+describe("viewTestResult", () => {
+	it("ok=true → no error, 'Connection OK' label", () => {
+		const r = viewTestResult({ alias: "buildbox", ok: true } as TestComputerResponse);
+		expect(r.ok).toBe(true);
+		expect(r.error).toBeNull();
+		expect(r.label).toBe("Connection OK");
+	});
+
+	it("ok=false → surfaces the failure reason", () => {
+		const r = viewTestResult({
+			alias: "buildbox",
+			ok: false,
+			error: "host unreachable",
+		} as TestComputerResponse);
+		expect(r.ok).toBe(false);
+		expect(r.error).toBe("host unreachable");
+		expect(r.label).toBe("Failed");
+	});
+
+	it("ok=false without a reason falls back to a default", () => {
+		const r = viewTestResult({ alias: "buildbox", ok: false } as TestComputerResponse);
+		expect(r.error).toBe("Connection failed");
+	});
+});
diff --git a/src/features/computer/logic/view-model.ts b/src/features/computer/logic/view-model.ts
new file mode 100644
index 0000000..944456b
--- /dev/null
+++ b/src/features/computer/logic/view-model.ts
@@ -0,0 +1,184 @@
+import type { ComputerStatusResponse, TestComputerResponse } from "@dispatch/transport-contract";
+import type { Computer, ComputerEntry } from "@dispatch/wire";
+
+/**
+ * Pure core for the computer feature — zero DOM, zero effects, zero Svelte.
+ *
+ * A **computer** is a remote SSH target discovered from the user's `~/.ssh/config`
+ * (read-only — there is no CRUD store; the user edits their config to add one).
+ * The computer feature surfaces, per-conversation and per-workspace, WHICH
+ * computer a turn's tools execute on (the computer analog of `cwd`). It is a
+ * USER-facing control only: the computer is a tool-execution target forwarded to
+ * tools and NEVER part of the model prompt (so it does not affect prompt
+ * caching) — the agent never sees it.
+ *
+ * This module holds the pure logic: formatting a `Computer` for display, mapping a
+ * live `ComputerStatusResponse.state` to a display badge, and the one-line
+ * discovered-list summary. The effects (the HTTP list/get/status/test +
+ * per-conversation get/set) are INJECTED via the ports below; the composition root
+ * implements them.
+ */
+
+// ── Injected ports (consumer-defines-port; the composition root adapts the
+//    store's HTTP calls to these shapes). Mirrors cwd-lsp's ports. ──────────────
+
+/** Outcome of `PUT /conversations/:id/computer`; `null` when no real conversation is focused. */
+export type ComputerSaveResult =
+	| { readonly ok: true; readonly computerId: string | null }
+	| { readonly ok: false; readonly error: string };
+
+export type SaveComputer = (computerId: string | null) => Promise<ComputerSaveResult | null>;
+
+/** Outcome of `GET /computers`; `null` when the list couldn't be loaded. */
+export type ComputerListResult =
+	| { readonly ok: true; readonly computers: readonly ComputerEntry[] }
+	| { readonly ok: false; readonly error: string };
+
+export type LoadComputers = () => Promise<ComputerListResult | null>;
+
+/** Outcome of `GET /computers/:alias/status`; `null` when no alias / not loaded. */
+export type ComputerStatusResult =
+	| { readonly ok: true; readonly status: ComputerStatusResponse }
+	| { readonly ok: false; readonly error: string };
+
+export type LoadComputerStatus = (alias: string) => Promise<ComputerStatusResult | null>;
+
+/** Outcome of `POST /computers/:alias/test`. */
+export type TestComputerResult =
+	| { readonly ok: true; readonly response: TestComputerResponse }
+	| { readonly ok: false; readonly error: string };
+
+export type TestComputer = (alias: string) => Promise<TestComputerResult | null>;
+
+// ── Computer → display view ──────────────────────────────────────────────────
+
+export type Badge = "success" | "warning" | "error" | "neutral";
+
+export interface ComputerView {
+	/** The SSH config `Host` alias — also the `computerId` users select. */
+	readonly alias: string;
+	/** A compact `user@host:port` connection string (the resolved config values). */
+	readonly hostSummary: string;
+	/** The resolved `IdentityFile`, or `null` = default `~/.ssh/id_*`. */
+	readonly identityFile: string | null;
+	/** Short label for the known-host indicator, e.g. "known host" / "new host". */
+	readonly knownHostLabel: string;
+	/** Whether the host's key is already in `~/.ssh/known_hosts`. */
+	readonly knownHost: boolean;
+}
+
+/**
+ * Format a computer's connection target as `user@host:port`, omitting the port
+ * when it is the SSH default (22) so the summary stays compact (mirrors how a user
+ * reads an ssh config `Host` block). `hostName` falls back to the alias itself
+ * (the backend resolves this, but this is defensive).
+ */
+export function formatHost(computer: Computer): string {
+	const host = computer.hostName || computer.alias;
+	const port = computer.port === 22 ? "" : `:${computer.port}`;
+	return `${computer.user}@${host}${port}`;
+}
+
+/** The display label for the known-host indicator. */
+export function knownHostLabel(knownHost: boolean): string {
+	return knownHost ? "known host" : "new host";
+}
+
+export function viewComputer(computer: Computer): ComputerView {
+	return {
+		alias: computer.alias,
+		hostSummary: formatHost(computer),
+		identityFile: computer.identityFile,
+		knownHostLabel: knownHostLabel(computer.knownHost),
+		knownHost: computer.knownHost,
+	};
+}
+
+export function viewComputers(computers: readonly ComputerEntry[]): readonly ComputerView[] {
+	return computers.map(viewComputer);
+}
+
+/**
+ * A one-line summary of the discovered list, e.g. "3 computers" / "No computers
+ * discovered" (the latter is the expected state until the `ssh` extension lands).
+ */
+export function summarizeComputers(computers: readonly ComputerEntry[]): string {
+	if (computers.length === 0) return "No computers discovered";
+	return `${computers.length} computer${computers.length === 1 ? "" : "s"}`;
+}
+
+// ── Connection status → display view ──────────────────────────────────────────
+
+export interface ComputerStatusView {
+	readonly alias: string;
+	readonly state: ComputerStatusResponse["state"];
+	readonly statusLabel: string;
+	readonly badge: Badge;
+	/** True while the state is transient (show a spinner). */
+	readonly busy: boolean;
+	/** The error reason when `state === "error"`, else null. */
+	readonly error: string | null;
+	/** Whether the host's key is already in `~/.ssh/known_hosts`. */
+	readonly knownHost: boolean;
+}
+
+/**
+ * Map a computer's live connection state to a display label + badge + busy flag.
+ * Mirrors the LSP/MCP status→badge pattern (each feature owns its own mapping —
+ * the enums differ, so they are not shared). Exhaustive vs the contract:
+ * `connected`→success, `connecting`→warning+busy, `disconnected`→neutral (a stable
+ * idle state, NOT busy), `error`→error.
+ */
+export function viewComputerStatus(status: ComputerStatusResponse): ComputerStatusView {
+	let statusLabel: string;
+	let badge: Badge;
+	let busy = false;
+	switch (status.state) {
+		case "connected":
+			statusLabel = "Connected";
+			badge = "success";
+			break;
+		case "connecting":
+			statusLabel = "Connecting…";
+			badge = "warning";
+			busy = true;
+			break;
+		case "disconnected":
+			statusLabel = "Disconnected";
+			badge = "neutral";
+			break;
+		case "error":
+			statusLabel = "Error";
+			badge = "error";
+			break;
+	}
+	return {
+		alias: status.alias,
+		state: status.state,
+		statusLabel,
+		badge,
+		busy,
+		error: status.state === "error" ? (status.error ?? "Connection failed") : null,
+		knownHost: status.knownHost,
+	};
+}
+
+// ── Test-connection result → display view ───────────────────────────────────
+
+export interface TestResultView {
+	readonly alias: string;
+	readonly ok: boolean;
+	/** The failure reason when `ok` is false, else null. */
+	readonly error: string | null;
+	/** A short result label, e.g. "Connection OK" / "Failed". */
+	readonly label: string;
+}
+
+export function viewTestResult(response: TestComputerResponse): TestResultView {
+	return {
+		alias: response.alias,
+		ok: response.ok,
+		error: response.ok ? null : (response.error ?? "Connection failed"),
+		label: response.ok ? "Connection OK" : "Failed",
+	};
+}
diff --git a/src/features/computer/ui/ComputerField.svelte b/src/features/computer/ui/ComputerField.svelte
new file mode 100644
index 0000000..be3ce9c
--- /dev/null
+++ b/src/features/computer/ui/ComputerField.svelte
@@ -0,0 +1,195 @@
+<script lang="ts">
+	import type { ComputerStatusResponse } from "@dispatch/transport-contract";
+	import ComputerSelect from "./ComputerSelect.svelte";
+	import {
+	viewComputerStatus,
+	type ComputerStatusView,
+	type LoadComputerStatus,
+	type SaveComputer,
+	type TestComputer,
+} from "../logic/view-model";
+	import type { ComputerEntry } from "@dispatch/wire";
+	import { untrack } from "svelte";
+
+	let {
+		computerId,
+		canEdit,
+		computers,
+		save,
+		loadStatus,
+		test,
+	}: {
+		/** The active conversation's persisted computer alias, or null (local/inherit). */
+		computerId: string | null;
+		/** Whether a real conversation is focused (a draft can't persist yet). */
+		canEdit: boolean;
+		/** Discovered computers from `GET /computers` (read-only). */
+		computers: readonly ComputerEntry[];
+		save: SaveComputer;
+		loadStatus: LoadComputerStatus;
+		test: TestComputer;
+	} = $props();
+
+	// ── Save: selecting a dropdown option persists immediately (PUT /computer). ──
+	let saving = $state(false);
+	let error = $state<string | null>(null);
+	let justSaved = $state(false);
+
+	async function select(computerId: string | null) {
+		if (saving || !canEdit) return;
+		saving = true;
+		error = null;
+		justSaved = false;
+		const result = await save(computerId);
+		saving = false;
+		if (result === null) return;
+		if (result.ok) {
+			justSaved = true;
+		} else {
+			error = result.error;
+		}
+	}
+
+	// ── Connection status: poll the selected computer's live state. Owned + ──
+	//    disposed here (never leaks across conversations — the field re-mounts per
+	//    conversation via the {#key} in App.svelte, like CwdField). No poll while
+	//    local (no alias) or while a draft can't persist.
+	let statusView = $state<ComputerStatusView | null>(null);
+	let statusError = $state<string | null>(null);
+
+	async function refreshStatus() {
+		const alias = untrack(() => computerId);
+		if (alias === null) {
+			statusView = null;
+			statusError = null;
+			return;
+		}
+		const result = await loadStatus(alias);
+		if (result === null) return;
+		if (result.ok) {
+			statusView = viewComputerStatus(result.status);
+			statusError = null;
+		} else {
+			statusView = null;
+			statusError = result.error;
+		}
+	}
+
+	// Re-fetch on mount + whenever the selected alias changes (incl. after a save).
+	$effect(() => {
+		void computerId;
+		void refreshStatus();
+	});
+
+	// Poll the status while a computer is selected. `connecting` is transient, so
+	// a faster cadence helps it flip to `connected`; a connected host is stable.
+	const POLL_MS = 4000;
+	$effect(() => {
+		const alias = computerId;
+		if (alias === null) return;
+		const handle = setInterval(() => void refreshStatus(), POLL_MS);
+		return () => clearInterval(handle);
+	});
+
+	// ── Test connection: one-shot probe (POST /computers/:alias/test). ──────────
+	let testing = $state(false);
+	let testResult = $state<{ ok: boolean; error: string | null } | null>(null);
+
+	async function runTest() {
+		const alias = untrack(() => computerId);
+		if (alias === null || testing) return;
+		testing = true;
+		testResult = null;
+		const result = await test(alias);
+		testing = false;
+		if (result === null) return;
+		testResult = result.ok
+			? { ok: true, error: null }
+			: { ok: false, error: result.error };
+	}
+
+	const badgeClass = $derived.by(() => {
+		const b = statusView?.badge ?? "neutral";
+		switch (b) {
+			case "success":
+				return "badge-success";
+			case "warning":
+				return "badge-warning";
+			case "error":
+				return "badge-error";
+			default:
+				return "badge-ghost";
+		}
+	});
+</script>
+
+<div class="flex flex-col gap-1">
+	<span class="text-xs font-semibold uppercase opacity-60">Computer (SSH)</span>
+	<div class="flex items-center gap-2">
+		<ComputerSelect
+			value={computerId}
+			{computers}
+			disabled={!canEdit || saving}
+			onSelect={select}
+		/>
+		{#if saving}
+			<span class="loading loading-spinner loading-xs shrink-0"></span>
+		{/if}
+	</div>
+
+	{#if !canEdit}
+		<p class="text-xs opacity-60">Start or open a conversation to set its computer.</p>
+	{:else if computerId !== null}
+		<!-- Connection status badge + Test affordance for the selected computer. -->
+		<div class="flex flex-wrap items-center gap-2">
+			{#if statusView}
+				<span class="badge badge-sm {badgeClass}" title={statusView.error ?? statusView.statusLabel}>
+					{#if statusView.busy}
+						<span class="loading loading-spinner loading-[10px]"></span>
+					{/if}
+					{statusView.statusLabel}
+				</span>
+			{:else if statusError}
+				<span class="badge badge-sm badge-error" title={statusError}>Status error</span>
+			{:else}
+				<span class="badge badge-sm badge-ghost">—</span>
+			{/if}
+
+			<button
+				type="button"
+				class="btn btn-ghost btn-xs"
+				disabled={testing}
+				onclick={runTest}
+			>
+				{#if testing}
+					<span class="loading loading-spinner loading-[10px]"></span>
+				{:else}
+					Test
+				{/if}
+			</button>
+
+			{#if testResult}
+				<span class="text-xs {testResult.ok ? 'text-success' : 'text-error'}">
+					{testResult.ok ? "Connection OK" : testResult.error ?? "Failed"}
+				</span>
+			{/if}
+		</div>
+		{#if statusView?.error}
+			<p class="text-xs text-error">{statusView.error}</p>
+		{/if}
+	{:else if computers.length === 0}
+		<p class="text-xs opacity-50">
+			No computers discovered — add a `Host` block to your `~/.ssh/config` to use a remote computer.
+		</p>
+	{:else if justSaved && !error}
+		<p class="text-xs text-success">Saved.</p>
+	{/if}
+
+	{#if error}
+		<p class="text-xs text-error">{error}</p>
+	{/if}
+
+	<p class="text-xs opacity-50">
+		Where this conversation's tools run. `null` (Local) runs on the server; an alias runs over SSH. Not seen by the agent.
+	</p>
+</div>
diff --git a/src/features/computer/ui/ComputerSelect.svelte b/src/features/computer/ui/ComputerSelect.svelte
new file mode 100644
index 0000000..d693140
--- /dev/null
+++ b/src/features/computer/ui/ComputerSelect.svelte
@@ -0,0 +1,39 @@
+<script lang="ts">
+	import type { ComputerEntry } from "@dispatch/wire";
+
+	let {
+		value,
+		computers,
+		disabled = false,
+		onSelect,
+	}: {
+		/** The currently selected computer alias, or null for "Local (none)". */
+		value: string | null;
+		/** Discovered computers from `GET /computers` (read-only). */
+		computers: readonly ComputerEntry[];
+		disabled?: boolean;
+		onSelect: (computerId: string | null) => void;
+	} = $props();
+
+	// A `<select>` value is a string; map "" ↔ null (Local). The chosen option's
+	// value is the alias, with "" meaning "clear / local".
+	const selectValue = $derived(value ?? "");
+
+	function onChange(e: Event) {
+		const v = (e.currentTarget as HTMLSelectElement).value;
+		onSelect(v === "" ? null : v);
+	}
+</script>
+
+<select
+	class="select select-bordered select-sm w-full font-mono text-xs"
+	value={selectValue}
+	disabled={disabled}
+	onchange={onChange}
+	aria-label="Computer"
+>
+	<option value="">Local (none)</option>
+	{#each computers as c (c.alias)}
+		<option value={c.alias}>{c.alias}{c.knownHost ? "" : " · new host"}</option>
+	{/each}
+</select>
diff --git a/src/features/workspaces/adapter/http.ts b/src/features/workspaces/adapter/http.ts
index 97fc2e2..6ebfee1 100644
--- a/src/features/workspaces/adapter/http.ts
+++ b/src/features/workspaces/adapter/http.ts
@@ -1,6 +1,7 @@
 import type {
 	DeleteWorkspaceResponse,
 	EnsureWorkspaceRequest,
+	SetWorkspaceDefaultComputerRequest,
 	SetWorkspaceDefaultCwdRequest,
 	SetWorkspaceTitleRequest,
 	Workspace,
@@ -23,6 +24,7 @@ import type {
  * - `GET /workspaces/:id` (404 → null) → get
  * - `PUT /workspaces/:id/title` → rename
  * - `PUT /workspaces/:id/default-cwd` → set/clear default cwd
+ * - `PUT /workspaces/:id/default-computer` → set/clear default computer (SSH handoff #2)
  * - `DELETE /workspaces/:id` (409 for "default") → delete
  */
 export type WorkspaceResult<T> =
@@ -35,6 +37,7 @@ export interface WorkspaceHttp {
 	get(id: string): Promise<Workspace | null>;
 	setTitle(id: string, title: string): Promise<WorkspaceResult<Workspace>>;
 	setDefaultCwd(id: string, defaultCwd: string | null): Promise<WorkspaceResult<Workspace>>;
+	setDefaultComputer(id: string, computerId: string | null): Promise<WorkspaceResult<Workspace>>;
 	delete(id: string): Promise<WorkspaceResult<{ closedCount: number }>>;
 }
 
@@ -118,6 +121,26 @@ export function createWorkspaceHttp(httpBase: string, fetchImpl: typeof fetch):
 			}
 		},
 
+		async setDefaultComputer(id, computerId): Promise<WorkspaceResult<Workspace>> {
+			try {
+				const res = await fetchImpl(
+					`${httpBase}/workspaces/${encodeURIComponent(id)}/default-computer`,
+					{
+						method: "PUT",
+						headers: { "Content-Type": "application/json" },
+						body: JSON.stringify({ computerId } satisfies SetWorkspaceDefaultComputerRequest),
+					},
+				);
+				if (!res.ok) return { ok: false, error: await errText(res) };
+				return { ok: true, value: (await res.json()) as WorkspaceResponse };
+			} catch (err) {
+				return {
+					ok: false,
+					error: err instanceof Error ? err.message : "Set default computer failed",
+				};
+			}
+		},
+
 		async delete(id): Promise<WorkspaceResult<{ closedCount: number }>> {
 			try {
 				const res = await fetchImpl(`${httpBase}/workspaces/${encodeURIComponent(id)}`, {
diff --git a/src/features/workspaces/logic/view-model.test.ts b/src/features/workspaces/logic/view-model.test.ts
index 52f7025..a4ed19c 100644
--- a/src/features/workspaces/logic/view-model.test.ts
+++ b/src/features/workspaces/logic/view-model.test.ts
@@ -36,6 +36,7 @@ describe("pageTitle", () => {
 		id,
 		title,
 		defaultCwd: null,
+		defaultComputerId: null,
 		createdAt: 0,
 		lastActivityAt: 0,
 		conversationCount: 0,
diff --git a/src/features/workspaces/store.svelte.ts b/src/features/workspaces/store.svelte.ts
index 0f662dc..0cf4ce2 100644
--- a/src/features/workspaces/store.svelte.ts
+++ b/src/features/workspaces/store.svelte.ts
@@ -21,6 +21,8 @@ export interface WorkspaceStore {
 	rename(id: string, title: string): Promise<WorkspaceResult<Workspace>>;
 	/** Set/clear a workspace's default cwd. */
 	setDefaultCwd(id: string, defaultCwd: string | null): Promise<WorkspaceResult<Workspace>>;
+	/** Set/clear a workspace's default computer (SSH `Host` alias; null = local). */
+	setDefaultComputer(id: string, computerId: string | null): Promise<WorkspaceResult<Workspace>>;
 	/** Delete a workspace (closes its conversations, reassigns to "default"). */
 	remove(id: string): Promise<WorkspaceResult<{ closedCount: number }>>;
 }
@@ -71,6 +73,12 @@ export function createWorkspaceStore(http: WorkspaceHttp): WorkspaceStore {
 			return result;
 		},
 
+		async setDefaultComputer(id, computerId): Promise<WorkspaceResult<Workspace>> {
+			const result = await http.setDefaultComputer(id, computerId);
+			if (result.ok) void this.refresh();
+			return result;
+		},
+
 		async remove(id): Promise<WorkspaceResult<{ closedCount: number }>> {
 			const result = await http.delete(id);
 			if (result.ok) void this.refresh();
diff --git a/src/features/workspaces/ui/WorkspaceCard.svelte b/src/features/workspaces/ui/WorkspaceCard.svelte
index 6348bb9..4f846bf 100644
--- a/src/features/workspaces/ui/WorkspaceCard.svelte
+++ b/src/features/workspaces/ui/WorkspaceCard.svelte
@@ -1,18 +1,22 @@
 <script lang="ts">
-	import type { WorkspaceEntry } from "@dispatch/wire";
+	import type { ComputerEntry, WorkspaceEntry } from "@dispatch/wire";
 	import { untrack } from "svelte";
 	import type { WorkspaceStore } from "../store.svelte";
 	import { relativeTime } from "../logic/view-model";
 	import { workspacePath } from "../logic/route";
+	import ComputerSelect from "../../computer/ui/ComputerSelect.svelte";
 
 	let {
 		ws,
 		store,
 		onNavigate,
+		computers,
 	}: {
 		ws: WorkspaceEntry;
 		store: WorkspaceStore;
 		onNavigate: (path: string) => void;
+		/** Discovered computers (`GET /computers`), for the default-computer dropdown. */
+		computers: readonly ComputerEntry[];
 	} = $props();
 
 	// ── Title: double-click to rename inline ──────────────────────────────────
@@ -64,6 +68,21 @@
 		if (!result.ok) cwdError = result.error;
 	}
 
+	// ── Default computer: dropdown (Local / discovered SSH aliases) ────────────
+	let savingComputer = $state(false);
+	let computerError = $state<string | null>(null);
+
+	async function saveComputer(computerId: string | null): Promise<void> {
+		if (savingComputer) return;
+		// No-op when unchanged (the select only fires on a real change, but guard).
+		if (computerId === (ws.defaultComputerId ?? null)) return;
+		savingComputer = true;
+		computerError = null;
+		const result = await store.setDefaultComputer(ws.id, computerId);
+		savingComputer = false;
+		if (!result.ok) computerError = result.error;
+	}
+
 	// ── Delete ─────────────────────────────────────────────────────────────────
 	let deleting = $state(false);
 
@@ -159,6 +178,19 @@
 		</button>
 	</div>
 
+	<div class="flex items-center gap-2">
+		<span class="w-8 shrink-0 text-xs opacity-60">ssh</span>
+		<ComputerSelect
+			value={ws.defaultComputerId}
+			{computers}
+			disabled={savingComputer}
+			onSelect={saveComputer}
+		/>
+		{#if savingComputer}
+			<span class="loading loading-spinner loading-xs shrink-0"></span>
+		{/if}
+	</div>
+
 	<div class="flex justify-start">
 		<a
 			class="btn"
@@ -177,4 +209,10 @@
 	{:else if !cwdDirty && !ws.defaultCwd}
 		<p class="text-xs opacity-50">No default cwd set — conversations inherit the server default.</p>
 	{/if}
+
+	{#if computerError}
+		<p class="text-xs text-error">{computerError}</p>
+	{:else if !ws.defaultComputerId}
+		<p class="text-xs opacity-50">No default computer — conversations run locally (no SSH).</p>
+	{/if}
 </li>
diff --git a/src/features/workspaces/ui/WorkspaceCard.test.ts b/src/features/workspaces/ui/WorkspaceCard.test.ts
index 385856d..48b12b3 100644
--- a/src/features/workspaces/ui/WorkspaceCard.test.ts
+++ b/src/features/workspaces/ui/WorkspaceCard.test.ts
@@ -11,6 +11,7 @@ function fakeEntry(overrides: Partial<WorkspaceEntry> = {}): WorkspaceEntry {
 		id: "my-ws",
 		title: "My Workspace",
 		defaultCwd: null,
+		defaultComputerId: null,
 		createdAt: 1,
 		lastActivityAt: 2,
 		conversationCount: 3,
@@ -33,6 +34,12 @@ function fakeStore() {
 				value: fakeEntry({ id, defaultCwd }),
 			}),
 		),
+		setDefaultComputer: vi.fn(
+			async (id: string, computerId: string | null): Promise<WorkspaceResult<WorkspaceEntry>> => ({
+				ok: true,
+				value: fakeEntry({ id, defaultComputerId: computerId }),
+			}),
+		),
 		remove: vi.fn(
 			async (): Promise<WorkspaceResult<{ closedCount: number }>> => ({
 				ok: true,
@@ -47,7 +54,7 @@ describe("WorkspaceCard", () => {
 		const store = fakeStore() as unknown as WorkspaceStore;
 		const onNavigate = vi.fn();
 		render(WorkspaceCard, {
-			props: { ws: fakeEntry(), store, onNavigate },
+			props: { ws: fakeEntry(), store, onNavigate, computers: [] },
 		});
 		expect(screen.getByText("My Workspace")).toBeInTheDocument();
 		expect(screen.getByText("/my-ws")).toBeInTheDocument();
@@ -57,7 +64,9 @@ describe("WorkspaceCard", () => {
 	it("double-clicking the title reveals an edit input", async () => {
 		const user = userEvent.setup();
 		const store = fakeStore() as unknown as WorkspaceStore;
-		render(WorkspaceCard, { props: { ws: fakeEntry(), store, onNavigate: vi.fn() } });
+		render(WorkspaceCard, {
+			props: { ws: fakeEntry(), store, onNavigate: vi.fn(), computers: [] },
+		});
 
 		await user.dblClick(screen.getByText("My Workspace"));
 		expect(screen.getByLabelText("Workspace title")).toHaveValue("My Workspace");
@@ -66,7 +75,9 @@ describe("WorkspaceCard", () => {
 	it("renames via the store on Enter", async () => {
 		const user = userEvent.setup();
 		const store = fakeStore() as unknown as WorkspaceStore;
-		render(WorkspaceCard, { props: { ws: fakeEntry(), store, onNavigate: vi.fn() } });
+		render(WorkspaceCard, {
+			props: { ws: fakeEntry(), store, onNavigate: vi.fn(), computers: [] },
+		});
 
 		await user.dblClick(screen.getByText("My Workspace"));
 		const input = screen.getByLabelText("Workspace title");
@@ -80,7 +91,7 @@ describe("WorkspaceCard", () => {
 		const user = userEvent.setup();
 		const store = fakeStore() as unknown as WorkspaceStore;
 		render(WorkspaceCard, {
-			props: { ws: fakeEntry({ defaultCwd: "/old" }), store, onNavigate: vi.fn() },
+			props: { ws: fakeEntry({ defaultCwd: "/old" }), store, onNavigate: vi.fn(), computers: [] },
 		});
 
 		const input = screen.getByLabelText("Default working directory");
@@ -99,7 +110,7 @@ describe("WorkspaceCard", () => {
 		const user = userEvent.setup();
 		const store = fakeStore() as unknown as WorkspaceStore;
 		render(WorkspaceCard, {
-			props: { ws: fakeEntry({ defaultCwd: "/old" }), store, onNavigate: vi.fn() },
+			props: { ws: fakeEntry({ defaultCwd: "/old" }), store, onNavigate: vi.fn(), computers: [] },
 		});
 
 		const input = screen.getByLabelText("Default working directory");
@@ -113,7 +124,7 @@ describe("WorkspaceCard", () => {
 		const user = userEvent.setup();
 		const store = fakeStore() as unknown as WorkspaceStore;
 		const onNavigate = vi.fn();
-		render(WorkspaceCard, { props: { ws: fakeEntry(), store, onNavigate } });
+		render(WorkspaceCard, { props: { ws: fakeEntry(), store, onNavigate, computers: [] } });
 
 		await user.click(screen.getByRole("link", { name: "Open" }));
 		expect(onNavigate).toHaveBeenCalledWith("/my-ws");
diff --git a/src/features/workspaces/ui/WorkspacesHome.svelte b/src/features/workspaces/ui/WorkspacesHome.svelte
index 5894f0a..bdfd023 100644
--- a/src/features/workspaces/ui/WorkspacesHome.svelte
+++ b/src/features/workspaces/ui/WorkspacesHome.svelte
@@ -1,10 +1,16 @@
 <script lang="ts">
 	import { onMount } from "svelte";
+	import type { ComputerEntry } from "@dispatch/wire";
 	import type { WorkspaceStore } from "../store.svelte";
 	import { isValidSlug, workspacePath } from "../logic/route";
 	import WorkspaceCard from "./WorkspaceCard.svelte";
 
-	let { store, onNavigate }: { store: WorkspaceStore; onNavigate: (path: string) => void } = $props();
+	let {
+		store,
+		onNavigate,
+		computers,
+	}: { store: WorkspaceStore; onNavigate: (path: string) => void; computers: readonly ComputerEntry[] } =
+		$props();
 
 	onMount(() => {
 		void store.refresh();
@@ -78,7 +84,7 @@
 		{:else}
 			<ul class="flex flex-col gap-2">
 				{#each store.list as ws (ws.id)}
-					<WorkspaceCard {ws} {store} {onNavigate} />
+					<WorkspaceCard {ws} {store} {onNavigate} {computers} />
 				{/each}
 			</ul>
 		{/if}