diff --git a/src/lib/api.test.ts b/src/lib/api.test.ts
index abfc7de..ec3f5d9 100644
--- a/src/lib/api.test.ts
+++ b/src/lib/api.test.ts
@@ -56,7 +56,7 @@ describe("api client", () => {
     ]);
     const r = await api.ping();
     expect(r.ok).toBe(false);
-    expect(r.reason).toMatch(/401/);
+    expect(r.reason).toMatch(/rejected|401|sign-in/i);
   });
 
   it("workItems() returns the items array", async () => {
diff --git a/src/lib/api.ts b/src/lib/api.ts
index 9387b07..3f5dbf5 100644
--- a/src/lib/api.ts
+++ b/src/lib/api.ts
@@ -19,6 +19,14 @@ const DEFAULT_CONFIG: ApiConfig = {
 
 const TOKEN_KEY = "fm.mc.token.v1";
 
+function friendlyAuthError(status: number, kind: string): string {
+  if (status === 502 || status === 504) return `${kind} unavailable: the EA2 backend is not reachable from this environment right now. Try again shortly.`;
+  if (status === 503) return `${kind} unavailable: the auth service is temporarily down. Try again shortly.`;
+  if (status === 404) return `${kind} is not wired to this environment yet.`;
+  if (status === 401 || status === 403) return `${kind} rejected: check the email and password.`;
+  return `${kind} failed (HTTP ${status}). Try again or contact the operator on call.`;
+}
+
 let inflightLogin: Promise<string> | null = null;
 
 async function login(cfg: ApiConfig, signal?: AbortSignal): Promise<string> {
@@ -30,7 +38,7 @@ async function login(cfg: ApiConfig, signal?: AbortSignal): Promise<string> {
       body: JSON.stringify({ email: cfg.email }),
       signal,
     });
-    if (!r.ok) throw new Error(`dev-login ${r.status}`);
+    if (!r.ok) throw new Error(friendlyAuthError(r.status, "Developer sign-in"));
     const body = (await r.json()) as { access_token: string };
     sessionStorage.setItem(TOKEN_KEY, body.access_token);
     return body.access_token;
@@ -213,8 +221,7 @@ export const api = {
     };
     const r = await instrumentedFetch("POST", `${this.config.baseUrl}/api/v1/auth/login`, init, { email, password });
     if (!r.ok) {
-      const text = await r.text().catch(() => "");
-      throw new Error(`Login failed: ${r.status} ${text.slice(0, 100)}`);
+      throw new Error(friendlyAuthError(r.status, "Sign-in"));
     }
     const data = await r.json() as { access_token: string; refresh_token?: string };
     this.setBearer(data.access_token);
@@ -230,8 +237,7 @@ export const api = {
     };
     const r = await instrumentedFetch("POST", `${this.config.baseUrl}/api/v1/auth/dev-login`, init, { email });
     if (!r.ok) {
-      const text = await r.text().catch(() => "");
-      throw new Error(`Dev-login failed: ${r.status} ${text.slice(0, 100)}`);
+      throw new Error(friendlyAuthError(r.status, "Developer sign-in"));
     }
     const data = await r.json() as { access_token: string; refresh_token?: string };
     this.setBearer(data.access_token);
diff --git a/src/scenes/Login.tsx b/src/scenes/Login.tsx
index d944183..c0ae28f 100644
--- a/src/scenes/Login.tsx
+++ b/src/scenes/Login.tsx
@@ -206,9 +206,22 @@ export default function Login() {
                   key={p.key}
                   type="button"
                   className="persona-chip"
-                  onClick={() => setEmail(p.email)}
+                  onClick={async () => {
+                    setEmail(p.email);
+                    if (!devLoginEnabled) return;
+                    setLoading(true);
+                    setError(null);
+                    try {
+                      await loginAs(p.email, undefined, { method: "dev" });
+                      setScene("landing");
+                    } catch (err) {
+                      setError((err as Error).message);
+                    } finally {
+                      setLoading(false);
+                    }
+                  }}
                   disabled={loading}
-                  title={p.email}
+                  title={`Sign in as ${p.title}`}
                 >
                   {p.title}
                 </button>