v0.2: Simplify spec + add MCP gateway integration

Major revision based on first principles thinking:
- Simplified format: plain Markdown, human readable
- Focus on capabilities (Can/Cannot) not API schemas
- MCP gateway pointer for structured tool access
- Clear positioning vs robots.txt and llms.txt

The agents.md file is the handshake.
The MCP gateway is where real work happens.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

examples/weather-api.md

@@ -0,0 +1,106 @@
+# Example: Weather Service
+
+A simple weather API demonstrating minimal and practical agent.md usage.
+
+## agent.md
+
+```yaml
+---
+protocol_version: "0.1"
+name: "Weather Service"
+description: "Current weather and forecasts for any location"
+
+tools:
+  - name: get_current
+    description: "Get current weather conditions for a location"
+    endpoint: "GET /api/weather/current"
+    parameters:
+      type: object
+      properties:
+        location:
+          type: string
+          description: "City name, address, or coordinates (lat,lon)"
+        units:
+          type: string
+          enum: ["metric", "imperial"]
+          default: "metric"
+      required:
+        - location
+    response:
+      type: json
+      schema:
+        type: object
+        properties:
+          temperature:
+            type: number
+          feels_like:
+            type: number
+          humidity:
+            type: integer
+          conditions:
+            type: string
+          wind_speed:
+            type: number
+    auth: none
+    rate_limit: "60/minute"
+
+  - name: get_forecast
+    description: "Get weather forecast for upcoming days"
+    endpoint: "GET /api/weather/forecast"
+    parameters:
+      type: object
+      properties:
+        location:
+          type: string
+        days:
+          type: integer
+          minimum: 1
+          maximum: 14
+          default: 7
+        units:
+          type: string
+          enum: ["metric", "imperial"]
+          default: "metric"
+      required:
+        - location
+    auth: api_key
+    rate_limit: "30/minute"
+
+  - name: get_alerts
+    description: "Get active weather alerts for a location"
+    endpoint: "GET /api/weather/alerts"
+    parameters:
+      type: object
+      properties:
+        location:
+          type: string
+      required:
+        - location
+    auth: none
+
+auth:
+  api_key:
+    header: "X-Weather-Key"
+    obtain: "https://weather.example/api-keys"
+    description: "Free tier: 1000 requests/day"
+
+rate_limits:
+  global: "1000/day"
+
+contact:
+  url: "https://weather.example/api/docs"
+---
+
+# Weather API for Agents
+
+Simple, reliable weather data.
+
+## Free Tools
+- Current conditions (no key needed)
+- Weather alerts (no key needed)
+
+## API Key Required
+- Extended forecasts (up to 14 days)
+
+Get your free API key at weather.example/api-keys
+```