feat(cli): add --open flag to model-name chat command

dispatch <model> --text "..." --open now starts a new conversation AND
signals the frontend to open the tab — no need for a separate
'dispatch send --open' step.

4 files changed, 72 insertions, 1 deletions

diff --git a/frontend-conversation-open-handoff.md b/frontend-conversation-open-handoff.md
new file mode 100644
index 0000000..ae900eb
--- /dev/null
+++ b/frontend-conversation-open-handoff.md
@@ -0,0 +1,53 @@
+# FE handoff — conversation.open (CLI --open flag)
+
+Courier this to `../dispatch-web`. All changes are ADDITIVE.
+
+## What shipped (backend)
+
+The CLI's `--open` flag (`dispatch send <id> --text "..." --open`) calls
+`POST /conversations/:id/open`, which emits a `conversationOpened` bus event. The
+transport-ws extension subscribes and broadcasts a new WS message to ALL connected
+frontend clients.
+
+## New WS message (additive to `WsServerMessage`)
+
+```ts
+interface ConversationOpenMessage {
+  readonly type: "conversation.open";
+  readonly conversationId: string;
+}
+```
+
+The `type` is `"conversation.open"` — add it to the FE's `WsServerMessage` union
+handler. It arrives as a top-level WS message (not inside `chat.delta`).
+
+## What the FE needs to do
+
+1. **Handle the WS message** — when a `"conversation.open"` message arrives, open
+   (or focus) a tab for `conversationId`. The backend just signals; the FE decides
+   whether to actually open/focus or just notify.
+
+2. **Suggested behavior:**
+   - If the conversation is already open in a tab, focus that tab.
+   - If not, open a new tab for it (load its history via `GET /conversations/:id`).
+   - Do NOT auto-focus if the user is actively typing in another tab (optional —
+     your discretion).
+
+3. **No version bumps needed** — `@dispatch/transport-contract` already exports
+   `ConversationOpenMessage` (additive to `WsServerMessage` since `0.13.0`). The FE
+   just needs to add the `type: "conversation.open"` case to its WS message handler.
+
+## No other integration points
+
+- No new HTTP endpoints for the FE (the CLI calls `POST /conversations/:id/open`).
+- No new surface types.
+- No new `AgentEvent` types.
+- The message is a global broadcast (sent to ALL connected clients), not per-
+  conversation.
+
+## Notes
+
+- The `--open` flag can be combined with `--queue` (enqueue + signal) or used
+  without `--queue` (blocking send + signal).
+- Multiple clients (e.g. phone + laptop) all receive the broadcast — each decides
+  independently whether to open/focus.
diff --git a/packages/cli/src/args.test.ts b/packages/cli/src/args.test.ts
index 392d560..70a4868 100644
--- a/packages/cli/src/args.test.ts
+++ b/packages/cli/src/args.test.ts
@@ -51,6 +51,7 @@ describe("parseArgs", () => {
 				conversationId: undefined,
 				reasoningEffort: undefined,
 				showReasoning: false,
+				open: false,
 			});
 		});
 
@@ -66,6 +67,7 @@ describe("parseArgs", () => {
 				conversationId: undefined,
 				reasoningEffort: undefined,
 				showReasoning: false,
+				open: false,
 			});
 		});
 
@@ -100,6 +102,7 @@ describe("parseArgs", () => {
 				conversationId: "abc",
 				reasoningEffort: undefined,
 				showReasoning: true,
+				open: false,
 			});
 		});
 
@@ -115,6 +118,7 @@ describe("parseArgs", () => {
 				conversationId: undefined,
 				reasoningEffort: "high",
 				showReasoning: false,
+				open: false,
 			});
 		});
 
diff --git a/packages/cli/src/args.ts b/packages/cli/src/args.ts
index b4478b0..4d6652e 100644
--- a/packages/cli/src/args.ts
+++ b/packages/cli/src/args.ts
@@ -25,6 +25,7 @@ export type ParsedCommand =
 			readonly conversationId?: string | undefined;
 			readonly reasoningEffort?: ReasoningEffort | undefined;
 			readonly showReasoning: boolean;
+			readonly open: boolean;
 	  }
 	| { readonly kind: "list"; readonly server: string; readonly query?: string }
 	| { readonly kind: "read"; readonly server: string; readonly conversationId: string }
@@ -189,6 +190,7 @@ export function parseArgs(argv: readonly string[], opts: ParseOpts): ParsedComma
 	let conversationId: string | undefined;
 	let reasoningEffort: ReasoningEffort | undefined;
 	let showReasoning = false;
+	let open = false;
 	let server = opts.defaultServer;
 
 	for (let i = 1; i < argv.length; i++) {
@@ -218,6 +220,9 @@ export function parseArgs(argv: readonly string[], opts: ParseOpts): ParsedComma
 			case "--show-reasoning":
 				showReasoning = true;
 				break;
+			case "--open":
+				open = true;
+				break;
 			case "--effort":
 				if (i + 1 >= argv.length)
 					return {
@@ -256,5 +261,6 @@ export function parseArgs(argv: readonly string[], opts: ParseOpts): ParsedComma
 		conversationId,
 		reasoningEffort,
 		showReasoning,
+		open,
 	};
 }
diff --git a/packages/cli/src/main.ts b/packages/cli/src/main.ts
index dd8cfa8..04e7231 100644
--- a/packages/cli/src/main.ts
+++ b/packages/cli/src/main.ts
@@ -25,7 +25,7 @@ const USAGE = `Usage:
   dispatch list [<prefix>] [--server <url>]
   dispatch read <conversationId> [--server <url>]
   dispatch send <conversationId> --text "..." [--queue] [--open] [--cwd <dir>] [--effort <level>] [--server <url>]
-  dispatch <modelName> --text "..." [--file <path>] [--cwd <dir>] [--conversation <id>] [--effort <level>] [--server <url>] [--show-reasoning]
+  dispatch <modelName> --text "..." [--file <path>] [--cwd <dir>] [--conversation <id>] [--effort <level>] [--server <url>] [--show-reasoning] [--open]
   dispatch --help
 
 Effort levels: low, medium, high (default), xhigh, max`;
@@ -153,6 +153,14 @@ async function main(): Promise<void> {
 
 			if (conversationId) {
 				process.stdout.write(`\n[conversation] ${conversationId}\n`);
+
+				if (parsed.open) {
+					await openConversation(
+						{ fetchImpl: globalThis.fetch },
+						{ server: parsed.server, conversationId },
+					);
+					process.stdout.write(`Signaled frontend to open ${conversationId}\n`);
+				}
 			}
 			break;
 		}