feat: add MCP service interfaces

Co-Authored-By: Anda Bot <noreply@anda.bot>

Author: zensh

README.md

@@ -34,6 +34,10 @@ Agent Identity
       +--> Agent Discourse -- may resolve --> third-party Agent Profile service
 ```
 
+## MCP Service Interfaces
+
+Services that implement Agent Profile Protocol or Agent Discourse Protocol may also expose their capabilities through an MCP server for direct MCP client access. These MCP surfaces are adapters over the existing services, not new Agent Protocols. See [docs/mcp/service-interfaces/2025-11-25.md](docs/mcp/service-interfaces/2025-11-25.md).
+
 ## Maturity
 
 All specifications in this repository are currently **drafts**. Implementers should expect clarifications, test vectors, JSON Schemas, and conformance tests to be added before a stable 1.0 release.
@@ -54,6 +58,8 @@ docs/
     agent-identity/
     agent-profile/
     agent-discourse/
+  mcp/
+    service-interfaces/
 ```
 
 ## SDKs

README.zh-CN.md

@@ -34,6 +34,10 @@ Agent Identity
       +--> Agent Discourse -- may resolve --> third-party Agent Profile service
 ```
 
+## MCP Service Interfaces
+
+实现 Agent Profile Protocol 或 Agent Discourse Protocol 的服务也可以通过 MCP server 暴露服务能力，让 MCP client 直接连接调用。这些 MCP surface 是已有服务能力上的适配层，不是新的 Agent Protocols。参见 [docs/mcp/service-interfaces/2025-11-25.zh-CN.md](docs/mcp/service-interfaces/2025-11-25.zh-CN.md)。
+
 ## 成熟度
 
 本仓库中的所有规范当前均为 **草案**。在稳定的 1.0 版本发布前，实现者应预期规范将会增加澄清说明、测试向量、JSON Schema 和一致性测试。
@@ -54,6 +58,8 @@ docs/
     agent-identity/
     agent-profile/
     agent-discourse/
+  mcp/
+    service-interfaces/
 ```
 
 ## SDK

crates/agent-protocols/src/discourse.rs

@@ -17,6 +17,7 @@ use sha3::{Digest, Sha3_256};
 
 use crate::error::{Result, SdkError};
 use crate::identity::{verify_envelope, AgentId, Envelope, Event};
+use crate::mcp::McpServiceInterfaceDiscovery;
 
 pub const PROTOCOL: &str = "agent-discourse/1.0";
 
@@ -474,6 +475,8 @@ pub struct DiscourseProtocolDiscovery {
     pub profile: Option<ProfileResolverMetadata>,
     #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
     pub endpoints: BTreeMap<String, String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub mcp: Option<McpServiceInterfaceDiscovery>,
 }
 
 #[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]

crates/agent-protocols/src/lib.rs

@@ -9,6 +9,7 @@ pub mod error;
 #[cfg(feature = "http-client")]
 pub mod http_client;
 pub mod identity;
+pub mod mcp;
 pub mod profile;
 
 pub use error::{Result, SdkError};

crates/agent-protocols/src/mcp.rs

@@ -0,0 +1,65 @@
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+use std::collections::BTreeMap;
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub enum McpAuthorizationMode {
+    #[serde(rename = "none")]
+    None,
+    #[serde(rename = "agent-jwt")]
+    AgentJwt,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub struct McpAuthorizationMetadata {
+    pub mode: McpAuthorizationMode,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub agent_jwt_audience: Option<String>,
+}
+
+#[derive(Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
+pub struct McpServiceInterfaceDiscovery {
+    pub spec_version: String,
+    pub endpoint: String,
+    pub transport: String,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub authorization: Option<McpAuthorizationMetadata>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub tools: Vec<String>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub resources: Vec<String>,
+    #[serde(default, skip_serializing_if = "Vec::is_empty")]
+    pub prompts: Vec<String>,
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    pub extra: BTreeMap<String, Value>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn mcp_service_interface_discovery_round_trips() {
+        let discovery = McpServiceInterfaceDiscovery {
+            spec_version: "2025-11-25".to_owned(),
+            endpoint: "https://profiles.example.com/mcp".to_owned(),
+            transport: "streamable-http".to_owned(),
+            authorization: Some(McpAuthorizationMetadata {
+                mode: McpAuthorizationMode::AgentJwt,
+                agent_jwt_audience: Some("https://profiles.example.com".to_owned()),
+            }),
+            tools: vec!["agent_profile.get".to_owned()],
+            resources: vec!["agent-profile://profiles/{agent_id}".to_owned()],
+            prompts: Vec::new(),
+            extra: BTreeMap::new(),
+        };
+
+        let encoded = serde_json::to_value(&discovery).unwrap();
+        assert_eq!(encoded["spec_version"], "2025-11-25");
+        assert_eq!(encoded["authorization"]["mode"], "agent-jwt");
+        assert!(encoded.get("prompts").is_none());
+
+        let decoded: McpServiceInterfaceDiscovery = serde_json::from_value(encoded).unwrap();
+        assert_eq!(decoded, discovery);
+    }
+}

crates/agent-protocols/src/profile.rs

@@ -4,6 +4,7 @@ use std::collections::BTreeMap;
 
 use crate::error::{Result, SdkError};
 use crate::identity::{verify_envelope, AgentId, Envelope, Event};
+use crate::mcp::McpServiceInterfaceDiscovery;
 
 pub const PROTOCOL: &str = "agent-profile/1.0";
 pub const PROFILE_UPDATE: &str = "profile.update";
@@ -114,6 +115,8 @@ pub struct ProfileServiceDiscovery {
     pub protocol: String,
     pub service: String,
     pub endpoints: ProfileServiceEndpoints,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub mcp: Option<McpServiceInterfaceDiscovery>,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     pub features: Vec<String>,
 }