Fix connector Connect: use the link flow and surface failures

Root cause found by probing the live API: Composio v3 rejects
POST /connected_accounts for Composio-managed OAuth auth configs with a
400 pointing at POST /connected_accounts/link, and the renderer threw
the failure away inside a .then, so clicking Connect did nothing and no
browser opened.

- createConnectedAccount now calls POST /connected_accounts/link with
  auth_config_id and user_id and reads connected_account_id and
  redirect_url; the local mirror records INITIALIZING until the poll
  adopts Composio's real status.
- Connect failures (and a blocked external-URL open) now show as a
  single line on the page instead of vanishing.

src/main/services/composio/composio-client.ts

@@ -94,19 +94,21 @@ export class ComposioClient {
     return id;
   }
 
-  /** Starts a connection for a user; the redirect URL completes it in the browser. */
+  /**
+   * Starts a connection for a user; the redirect URL completes it in the
+   * browser. Composio-managed auth configs only accept the link flow —
+   * POST /connected_accounts is rejected for them with a 400.
+   */
   async createConnectedAccount(input: { authConfigId: string; userId: string }): Promise<{
     id: string;
-    status: string;
     redirectUrl: string | null;
   }> {
-    const response = await this.request("POST", `${BASE_URL}/connected_accounts`, {
-      auth_config: { id: input.authConfigId },
-      connection: { user_id: input.userId },
+    const response = await this.request("POST", `${BASE_URL}/connected_accounts/link`, {
+      auth_config_id: input.authConfigId,
+      user_id: input.userId,
     });
     return {
-      id: String(response.id ?? ""),
-      status: String(response.status ?? ""),
+      id: String(response.connected_account_id ?? ""),
       redirectUrl: typeof response.redirect_url === "string" ? response.redirect_url : null,
     };
   }

src/main/services/composio/composio-connection-service.ts

@@ -26,8 +26,10 @@ export class ComposioConnectionService {
   /**
    * Starts (or restarts) the company's connection for a toolkit: creates a
    * Composio-managed auth config once per toolkit, initiates the connected
-   * account for the company user, and records the pending account locally.
-   * The returned redirect URL completes authorization in the browser.
+   * account for the company user via the link flow, and records the pending
+   * account locally as INITIALIZING — the poll that follows adopts Composio's
+   * real status. The returned redirect URL completes authorization in the
+   * browser.
    */
   async connectToolkit(orgId: string, toolkitSlug: string, toolkitName: string): Promise<ConnectComposioToolkitResult> {
     const slug = normalizeSlug(toolkitSlug);
@@ -48,8 +50,8 @@ export class ComposioConnectionService {
         auth_config_id = excluded.auth_config_id,
         status = excluded.status,
         updated_at = excluded.updated_at
-    `).run(account.id, orgId, slug, toolkitName.trim() || slug, authConfigId, account.status || "INITIATED", now, now);
-    return { accountId: account.id, status: account.status, redirectUrl: account.redirectUrl };
+    `).run(account.id, orgId, slug, toolkitName.trim() || slug, authConfigId, "INITIALIZING", now, now);
+    return { accountId: account.id, redirectUrl: account.redirectUrl };
   }
 
   /** Pulls account statuses from Composio and updates the local mirror. */

src/renderer/src/pages/ConnectorsPage.tsx

@@ -26,6 +26,7 @@ export function ConnectorsPage({ snapshot, actions }: PageProps) {
   const employee = requireActiveEmployee(snapshot);
   const [catalogSlot, setCatalogSlot] = useState<CatalogSlot>(null);
   const [busySlug, setBusySlug] = useState<string | null>(null);
+  const [connectError, setConnectError] = useState<string | null>(null);
   const pollTimer = useRef<ReturnType<typeof setTimeout> | null>(null);
   const catalog: CatalogState = catalogSlot && catalogSlot.orgId === orgId ? catalogSlot.state : { phase: "loading" };
 
@@ -90,14 +91,19 @@ export function ConnectorsPage({ snapshot, actions }: PageProps) {
 
   const connect = (toolkit: ComposioToolkitSummaryDto) => {
     setBusySlug(toolkit.slug);
+    setConnectError(null);
     void window.agentCompany
       .connectComposioToolkit({ orgId, toolkitSlug: toolkit.slug, toolkitName: toolkit.name })
-      .then((result) => {
-        if (!result.ok) throw new Error(result.error.message);
-        if (result.data.redirectUrl) {
-          void window.agentCompany.openExternalUrl(result.data.redirectUrl);
+      .then(async (result) => {
+        if (!result.ok) {
+          setConnectError(result.error.message);
+          return;
         }
         pollUntilActive(toolkit.slug, 0);
+        if (result.data.redirectUrl) {
+          const opened = await window.agentCompany.openExternalUrl(result.data.redirectUrl);
+          if (!opened.ok) setConnectError(opened.error.message);
+        }
       })
       .finally(() => setBusySlug(null));
   };
@@ -112,6 +118,21 @@ export function ConnectorsPage({ snapshot, actions }: PageProps) {
     <div style={{ maxWidth: 1060 }}>
       <h2 style={{ margin: "0 0 18px", fontSize: 16, fontWeight: 600 }}>Connectors</h2>
 
+      {connectError && (
+        <div
+          style={{
+            color: "var(--text-2)",
+            fontSize: 13,
+            marginBottom: 14,
+            overflow: "hidden",
+            textOverflow: "ellipsis",
+            whiteSpace: "nowrap",
+          }}
+        >
+          {connectError}
+        </div>
+      )}
+
       <ConnectedList accounts={accounts} grants={grants} agents={agents} onGrant={grant} onRevoke={revoke} />
 
       {catalog.phase === "loading" && (

src/shared/commands/composio.ts

@@ -21,7 +21,6 @@ export interface ConnectComposioToolkitInput {
 
 export interface ConnectComposioToolkitResult {
   accountId: string;
-  status: string;
   redirectUrl: string | null;
 }