expand detection signatures from agent infrastructure research

Infra domains (12 -> 45): add MCP registries (registry.smithery.ai,
server.smithery.ai, registry.modelcontextprotocol.io, mcp.run, mcp.so,
pulsemcp.com, mcphub.tools, opentools.com, mcpindex.net), observability
platforms (cloud.langfuse.com, eu.api.smith.langchain.com, braintrust,
agentops, wandb weave, arize phoenix, llamatrace), deployment/sandbox
(e2b, toolhouse, composio backend), IDE agent backends (cursor.sh,
githubcopilot.com, windsurf.com)

Domain suffixes (9 -> 16): add .run.tools (Smithery remote MCP),
.e2b.dev (sandbox), .modal.run, .fly.dev, .replit.dev, .repl.co,
.gcpp.cursor.sh (Cursor regional endpoints)

Frameworks (58 -> 69): add anthropic_sdk (x-stainless-* headers),
google_genai_sdk, claude_desktop, opencode, blackboxai, mcp_inspector,
strands_agents, google_adk, vercel_ai_sdk, e2b, agentops. Expand
existing: cursor (x-cursor-* headers, x-ghost-mode), copilot
(GithubCopilot UA, Editor-Version/Plugin-Version headers), claude_code
(anthropic-beta header), openai_assistants (x-stainless-* headers,
OpenAI-Beta), helicone (full Helicone-* header family), portkey
(full x-portkey-* header family), braintrust (x-bt-* headers).
Add mcp_client_name field for MCP initialize fingerprinting.

MCP detector: add MCP-Protocol-Version header detection (definitive
MCP indicator), streamable HTTP transport headers, /events and
/message paths for legacy SSE transport

Endpoint prober: add MEMORY.md and .well-known/agent-identity.json
to metadata paths

MCP methods: add sampling/createMessage

Author: symbibot

agentsniff/cli.py

@@ -15,7 +15,7 @@
 
 from agentsniff.baseline import NetworkBaseline
 from agentsniff.config import ScanConfig, default_config_yaml
-from agentsniff.signatures import get_signature_data, VERIFIED, INVALID, UNVERIFIED
+from agentsniff.signatures import get_signature_data, VERIFIED, INVALID
 from agentsniff.notifier import should_alert, send_alerts
 from agentsniff.scanner import run_scan
 from agentsniff.storage import ScanStore
@@ -72,7 +72,6 @@ def _print_signature_status():
 
     invalid = [k for k, v in status.items() if v == INVALID]
     verified = [k for k, v in status.items() if v == VERIFIED]
-    unverified = [k for k, v in status.items() if v == UNVERIFIED]
 
     if invalid:
         print(

agentsniff/detectors/dns_monitor.py

@@ -13,7 +13,7 @@
 import struct
 from datetime import datetime, timezone
 
-from agentsniff.config import AGENT_INFRA_DOMAINS, LLM_API_DOMAIN_SUFFIXES, ScanConfig
+from agentsniff.config import LLM_API_DOMAIN_SUFFIXES, ScanConfig
 from agentsniff.detectors.base import BaseDetector, DetectorRegistry
 from agentsniff.models import Confidence, DetectionSignal, DetectorType
 

agentsniff/detectors/endpoint_prober.py

@@ -29,9 +29,11 @@
     "/.well-known/agents.json",
     "/.well-known/ai-plugin.json",
     "/.well-known/clawhub.json",
+    "/.well-known/agent-identity.json",
     "/AGENTS.md",
     "/SKILL.md",
     "/SOUL.md",
+    "/MEMORY.md",
 ]
 
 # Paths that indicate OpenAPI/Swagger specs (common in agent API frameworks)

agentsniff/detectors/mcp_detector.py

@@ -19,7 +19,7 @@
 logger = logging.getLogger("agentsniff.mcp_detector")
 
 # Common MCP server paths
-MCP_PATHS = ["/mcp", "/sse", "/mcp/sse", "/jsonrpc", "/rpc", "/api/mcp", "/v1/mcp"]
+MCP_PATHS = ["/mcp", "/sse", "/events", "/mcp/sse", "/message", "/jsonrpc", "/rpc", "/api/mcp", "/v1/mcp"]
 
 # Common MCP ports
 MCP_PORTS = [3000, 3001, 8080, 8000, 8001, 5000, 9000]
@@ -119,21 +119,49 @@ async def _try_jsonrpc_init(
         }
 
         try:
+            # Use streamable HTTP transport headers (MCP 2025-03-26+)
+            headers = {
+                "Content-Type": "application/json",
+                "Accept": "application/json, text/event-stream",
+                "MCP-Protocol-Version": "2025-03-26",
+            }
             async with session.post(
                 url,
                 json=init_request,
-                headers={"Content-Type": "application/json"},
+                headers=headers,
             ) as resp:
                 if resp.status not in (200, 201):
                     return []
 
+                # Check for MCP-Protocol-Version in response headers
+                resp_mcp_version = resp.headers.get("MCP-Protocol-Version")
+                resp_session_id = resp.headers.get("Mcp-Session-Id")
+
                 body = await resp.text()
                 try:
                     data = json.loads(body)
                 except json.JSONDecodeError:
                     return []
 
-                return self._analyze_jsonrpc_response(data, host, port, path, url)
+                signals = self._analyze_jsonrpc_response(data, host, port, path, url)
+
+                # MCP-Protocol-Version header is a definitive MCP indicator
+                if resp_mcp_version and not signals:
+                    signals.append(DetectionSignal(
+                        detector=DetectorType.MCP_DETECTOR,
+                        signal_type="mcp_protocol_header",
+                        description=f"MCP-Protocol-Version header: {resp_mcp_version}",
+                        confidence=Confidence.CONFIRMED,
+                        evidence={
+                            "host": host,
+                            "port": port,
+                            "path": path,
+                            "protocol_version": resp_mcp_version,
+                            "session_id": resp_session_id,
+                        },
+                    ))
+
+                return signals
 
         except (aiohttp.ClientError, asyncio.TimeoutError, OSError):
             return []

agentsniff/signatures/agent_infra_domains.json

@@ -5,10 +5,43 @@
   "api.moltyverse.email",
   "moltyverse.app",
   "smithery.ai",
+  "registry.smithery.ai",
+  "server.smithery.ai",
   "glama.ai",
+  "registry.modelcontextprotocol.io",
+  "staging.registry.modelcontextprotocol.io",
+  "mcp.run",
+  "mcp.so",
+  "pulsemcp.com",
+  "mcphub.tools",
+  "mcp.composio.dev",
+  "opentools.com",
+  "mcpindex.net",
   "api.langfuse.com",
+  "cloud.langfuse.com",
+  "us.cloud.langfuse.com",
   "api.smith.langchain.com",
+  "eu.api.smith.langchain.com",
+  "hub.langchain.com",
   "api.helicone.ai",
+  "gateway.helicone.ai",
+  "ai-gateway.helicone.ai",
+  "api.braintrust.dev",
+  "api.agentops.ai",
+  "otlp.agentops.ai",
+  "trace.wandb.ai",
+  "app.phoenix.arize.com",
+  "llamatrace.com",
   "api.composio.dev",
-  "app.composio.dev"
+  "app.composio.dev",
+  "backend.composio.dev",
+  "app.toolhouse.ai",
+  "api.e2b.dev",
+  "api.portkey.ai",
+  "api2.cursor.sh",
+  "api4.cursor.sh",
+  "cursor.sh",
+  "api.githubcopilot.com",
+  "api.business.githubcopilot.com",
+  "windsurf.com"
 ]

agentsniff/signatures/domain_suffixes.json

@@ -7,5 +7,12 @@
   ".ml.cloud.ibm.com",
   ".cognitiveservices.azure.com",
   ".inference.ai.azure.com",
-  ".volces.com"
+  ".volces.com",
+  ".run.tools",
+  ".e2b.dev",
+  ".modal.run",
+  ".fly.dev",
+  ".replit.dev",
+  ".repl.co",
+  ".gcpp.cursor.sh"
 ]