# Dual-Audience Development Guide: Agent-First APIs & Mobile-First SSR UI

This guide outlines the architectural blueprint and best practices for building modern services within the **Auth-Yes Zero-Trust Ecosystem**.

---

## 1. The Core Philosophy: Dual-Audience Architecture

Every modern application should be built for **two primary audiences**:
1. **🤖 AI Agents & Workloads (Primary Data Consumer):**
   - Headless execution via **Model Context Protocol (MCP)**, REST APIs, or ConnectRPC.
   - Machine-readable, high-density JSON/RPC responses with zero HTML/CSS clutter.
   - Authentication via **Delegated Bearer Tokens (`ay_sess_...`)** or mTLS SPIFFE workload identities.
2. **📱 Humans on Mobile Devices (Primary UI Consumer):**
   - Ultra-fast, zero-friction **Server-Side Rendered (SSR) JSX** touch cards.
   - Passkey (WebAuthn) biometric authentication.
   - Single Sign-On (SSO) entry via the **Auth-Yes Application Launchpad**.

---

## 2. Architectural Blueprint for Subsidiary Apps (e.g. `ed-droid`)

```
                               +---------------------------------------+
                               |         Traefik Edge Ingress          |
                               +---------------------------------------+
                                                   |
                             ForwardAuth Check     |  (Injects X-Forwarded-*)
                          +------------------------+------------------------+
                          |                                                 |
                          v                                                 v
              +-----------------------+                         +-----------------------+
              |   Auth-Yes Service    |                         |    Subsidiary App     |
              | (Validates Session /  |                         |   (e.g., ed-droid)    |
              |  Bearer Token)        |                         +-----------------------+
              +-----------------------+                                     |
                                                                            |
                                               +----------------------------+----------------------------+
                                               |                                                         |
                                               v                                                         v
                                    [ /api/* JSON Endpoints ]                                 [ SSR HTML Mobile Cards ]
                                    - Served for AI Agents & MCP                              - Served for Human Browsers
                                    - Filtered by Scopes / Roles                              - Clean, high-contrast UI
```

---

## 3. How to Build an "Agent-First" Subsidiary App

### Step 1: Ingress Protection via ForwardAuth
In your Traefik/Compose configuration, protect your service domain with Auth-Yes ForwardAuth middleware:
```yaml
labels:
  - "traefik.http.routers.ed-droid.middlewares=auth-yes-forwardauth@docker"
```
When requests arrive:
* Traefik queries `http://auth-api:8000/api/forward-auth`.
* Auth-Yes validates either the browser's `session_id` cookie **or** the incoming `Authorization: Bearer ay_sess_...` token.
* If authorized, Traefik injects:
  - `X-Forwarded-User: <username>`
  - `X-Forwarded-User-Id: <uuid>`
  - `X-Forwarded-Scopes: <scope1,scope2>`
  - `X-Forwarded-App-Id: <app_id>`

### Step 2: Implement Clean JSON API Routes
Provide standard JSON endpoints for all core operations:
```typescript
import { Hono } from "jsr:@hono/hono";

const app = new Hono();

// AI Agents & APIs consume JSON directly:
app.get("/api/fleet", (c) => {
  const user = c.req.header("X-Forwarded-User");
  const fleetData = getFleetForUser(user);
  return c.json({ fleet: fleetData });
});
```

### Step 3: Progressive Content Negotiation (Optional)
If a route serves both humans and AI agents without separate `/api` prefixes, inspect the `Accept` header or `?format=json` query:
```typescript
app.get("/ships/:id", (c) => {
  const ship = getShip(c.req.param("id"));
  
  // If requested by an agent or CLI:
  if (c.req.header("Accept")?.includes("application/json") || c.req.query("format") === "json") {
    return c.json(ship);
  }
  
  // If requested by a human browser:
  return c.html(ShipCardView({ ship }));
});
```

---

## 4. Connecting AI Agents via Model Context Protocol (MCP)

To expose your subsidiary applications to AI assistants (Antigravity, Jules, Claude Desktop):

1. **Mint a Delegated Session in Auth-Yes:**
   - Go to `https://auth.atyg.org/dashboard/sessions` $\rightarrow$ Click **`+ Delegate Agent Session`**.
   - Set Label: `"Antigravity Assistant"`, Lifespan: `12 Hours`, Scope: `ed-droid`.
   - Copy the CLI export string.

2. **Configure the MCP Server:**
   ```json
   {
     "mcpServers": {
       "ed-droid": {
         "command": "deno",
         "args": ["run", "-A", "https://git.atyg.org/tylerg/ed-droid/raw/branch/main/mcp/server.ts"],
         "env": {
           "AUTH_YES_TOKEN": "ay_sess_8de186f564d7..."
         }
       }
     }
   }
   ```

3. **Tool Call Execution:**
   The MCP server attaches `Authorization: Bearer $AUTH_YES_TOKEN` to all internal fetch calls, gaining instant authorized access to fleet telemetry and data with full Merkle audit attribution!

---

## 5. Ephemeral Guest & Support Passes (Magic 1-Click Links)

In addition to Agent Bearer Tokens, Auth-Yes supports **Ephemeral Magic Passes** for friends and external support technicians:

### The Flow:
1. **Spawn Pass:** Under Sessions, click **`+ Spawn Guest / Support Pass`**:
   - **Label:** *"Friend Demo - Elite Dangerous Fleet"*
   - **Lifespan:** *2 Hours* (auto-expires)
   - **Target App:** `ed-droid.atyg.org`
2. **Share 1-Click Link:**
   `https://auth.atyg.org/pass?token=ay_pass_9f8a7b6c...`
3. **Instant Redemption:**
   - When opened in any browser, Auth-Yes automatically sets the `.atyg.org` session cookie with restricted scopes.
   - The browser is immediately redirected to `https://ed-droid.atyg.org`.
   - **Zero friction:** No passkeys to register, no passwords, no email confirmation.
4. **Security & Control:**
   - The guest only has access to the specified target app.
   - The pass is visible on your Sessions dashboard in real time with an instant **`[Revoke]`** button.