Add AID v2 well-known discovery

docs/INTERFACE.md

@@ -5,6 +5,7 @@
 - Host: https://agent-guild-5d5r.onrender.com
 - MCP (streamable HTTP): https://agent-guild-5d5r.onrender.com/mcp/
 - MCP x402 payment safety: https://agent-guild-5d5r.onrender.com/mcp/payment-safety/
+- AID v2 discovery: https://agent-guild-5d5r.onrender.com/.well-known/agent
 - ARD catalogue: https://agent-guild-5d5r.onrender.com/.well-known/ai-catalog.json
 - A2A JSON-RPC: https://agent-guild-5d5r.onrender.com/a2a · agent card: https://agent-guild-5d5r.onrender.com/.well-known/agent-card.json
 - Issuer DID: https://agent-guild-5d5r.onrender.com/.well-known/agent-guild-did.json
@@ -24,6 +25,7 @@ guild_mediated requires two-party cryptographic participation, a Guild-observed
 
 - `GET /`
 - `GET /.well-known/402index-verify.txt`
+- `GET /.well-known/agent`
 - `GET /.well-known/agent-guild-did.json`
 - `GET /.well-known/agent-guild.json`
 - `GET /.well-known/agent-skills/agent-guild/SKILL.md`

live/guild/app/main.py

@@ -230,6 +230,7 @@ async def _lifespan(app: "FastAPI"):
 # exactly ONE row per fetch here; downstream measurement deduplicates the
 # privacy-safe actor and excludes our traffic, generic tools and crawlers.
 _DISCOVERY_RESOURCE_SURFACES = {
+    "/.well-known/agent": "aid_v2",
     "/.well-known/ai-catalog.json": "ard_catalog",
     "/.well-known/agent-guild.json": "guild_manifest",
     "/.well-known/integrations.json": "integrations_owner_declaration",
@@ -3897,6 +3898,7 @@ def _manifest() -> dict:
         },
         "discovery": {
             "capabilities": "/capabilities",
+            "aid_v2": "/.well-known/agent",
             "ard_catalog": "/.well-known/ai-catalog.json",
             "ard_agentmap": "/robots.txt",
             "discovery_census": {
@@ -4601,6 +4603,29 @@ def wellknown_integrations():
     )
 
 
+@app.get("/.well-known/agent")
+def wellknown_aid_v2():
+    """AID v2 HTTPS fallback for domain-first agent discovery.
+
+    Agent Identity & Discovery clients query ``_agent.<host>`` first and may
+    fall back to this exact path when no DNS TXT record exists.  Keep the
+    record deliberately minimal: TLS already binds it to this host, and
+    omitting ``k`` avoids claiming the separate RFC 9421 PKA profile.
+    """
+    base = x402.public_host().rstrip("/")
+    return JSONResponse(
+        content={
+            "v": "aid2",
+            "u": f"{base}/mcp",
+            "p": "mcp",
+            "a": "none",
+            "s": "Agent Guild trust and settlement",
+            "d": f"{base}/for-agents",
+        },
+        headers={"Cache-Control": "public, max-age=300, s-maxage=300"},
+    )
+
+
 @app.get("/.well-known/mcp/payment-safety-server-card.json")
 async def wellknown_payment_safety_mcp_server_card():
     """Static discovery for the focused, one-tool payment-safety server."""

live/guild/contract/contract.json

@@ -212,6 +212,12 @@
    ],
    "path": "/.well-known/402index-verify.txt"
   },
+  {
+   "methods": [
+    "GET"
+   ],
+   "path": "/.well-known/agent"
+  },
   {
    "methods": [
     "GET"
@@ -1109,6 +1115,7 @@
  "service": {
   "a2a_endpoint": "https://agent-guild-5d5r.onrender.com/a2a",
   "agent_card": "https://agent-guild-5d5r.onrender.com/.well-known/agent-card.json",
+  "aid_well_known": "https://agent-guild-5d5r.onrender.com/.well-known/agent",
   "ard_catalog": "https://agent-guild-5d5r.onrender.com/.well-known/ai-catalog.json",
   "did_web_document": "https://agent-guild-5d5r.onrender.com/.well-known/did.json",
   "host": "https://agent-guild-5d5r.onrender.com",

live/guild/contract/generate.py

@@ -81,6 +81,7 @@ def build_contract() -> dict:
                 f"{HOST}/.well-known/mcp/"
                 "payment-safety-server-card.json"
             ),
+            "aid_well_known": f"{HOST}/.well-known/agent",
             "ard_catalog": f"{HOST}/.well-known/ai-catalog.json",
             "a2a_endpoint": f"{HOST}/a2a",
             "agent_card": f"{HOST}/.well-known/agent-card.json",
@@ -409,6 +410,7 @@ def derived_interface_md(contract: dict) -> str:
         f"- Host: {s['host']}",
         f"- MCP (streamable HTTP): {s['mcp_url']}",
         f"- MCP x402 payment safety: {s['payment_safety_mcp_url']}",
+        f"- AID v2 discovery: {s['aid_well_known']}",
         f"- ARD catalogue: {s['ard_catalog']}",
         f"- A2A JSON-RPC: {s['a2a_endpoint']} · agent card: {s['agent_card']}",
         f"- Issuer DID: {s['issuer_did_document']}",

live/guild/tests/test_agent_native.py

@@ -16,6 +16,7 @@ def test_discovery_manifest_describes_service():
     assert m["economics"]["pricing_credits"]["best_agent"] == PRICING["best_agent"]
     # an agent can learn how to acquire credits with no human
     assert m["economics"]["acquire_credits"]["trial"]["human_free"] is True
+    assert m["discovery"]["aid_v2"] == "/.well-known/agent"
     assert "measured_lift" in m["evaluation_signals"]
 
 

live/guild/tests/test_aid_discovery.py

@@ -0,0 +1,54 @@
+"""Agent Identity & Discovery (AID) v2 HTTPS fallback."""
+from urllib.parse import urlparse
+
+from fastapi.testclient import TestClient
+
+from app import main, x402
+
+
+def test_aid_v2_well_known_fallback_is_valid_and_cacheable():
+    client = TestClient(main.app)
+    response = client.get(
+        "/.well-known/agent",
+        headers={"user-agent": "aid-python/2.1"},
+        follow_redirects=False,
+    )
+
+    assert response.status_code == 200
+    assert response.headers["content-type"].startswith("application/json")
+    assert response.headers["cache-control"] == (
+        "public, max-age=300, s-maxage=300")
+    assert len(response.content) < 64 * 1024
+
+    base = x402.public_host().rstrip("/")
+    assert response.json() == {
+        "v": "aid2",
+        "u": f"{base}/mcp",
+        "p": "mcp",
+        "a": "none",
+        "s": "Agent Guild trust and settlement",
+        "d": f"{base}/for-agents",
+    }
+    assert urlparse(response.json()["u"]).scheme == "https"
+    assert len(response.json()["s"].encode("utf-8")) <= 60
+
+
+def test_aid_fetch_is_one_noncommercial_discovery_observation():
+    client = TestClient(main.app)
+    before = len(main.store.events)
+
+    response = client.get(
+        "/.well-known/agent",
+        headers={"user-agent": "aid-python/2.1"},
+    )
+
+    assert response.status_code == 200
+    new = main.store.events[before:]
+    observations = [event for event in new
+                    if event["type"] == "discovery_resource_fetched"]
+    assert len(observations) == 1
+    assert observations[0]["discovery_surface"] == "aid_v2"
+    assert not any(event["type"] in {
+        "capability_demand", "offer_served", "paid_offer_served",
+        "paid_offer_shown",
+    } for event in new)