feat(l7): add JSON-RPC policy enforcement

.github/workflows/e2e-test.yml

@@ -44,6 +44,9 @@ jobs:
             cmd: "mise run --no-deps --skip-deps e2e:podman:rootless"
             apt_packages: "openssh-client podman uidmap"
             rootless: true
+          - suite: mcp
+            cmd: "mise run --no-deps --skip-deps e2e:mcp"
+            apt_packages: ""
     container:
       image: ghcr.io/nvidia/openshell/ci:latest
       credentials:
@@ -65,6 +68,17 @@ jobs:
       - uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
         with:
           ref: ${{ inputs['checkout-ref'] || github.sha }}
+          persist-credentials: false
+
+      - name: Check out MCP conformance tests
+        if: matrix.suite == 'mcp'
+        uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+        with:
+          repository: modelcontextprotocol/conformance
+          # Pin after v0.1.16 to include the tools_call client scenario fix.
+          ref: b9041ea41b0188581803459dbae71bc7e02fd995
+          path: .cache/mcp-conformance
+          persist-credentials: false
 
       - name: Install OS test dependencies
         if: matrix.apt_packages != ''
@@ -104,6 +118,7 @@ jobs:
       - name: Run tests
         env:
           OPENSHELL_SUPERVISOR_IMAGE: ${{ format('ghcr.io/nvidia/openshell/supervisor:{0}', inputs.image-tag) }}
+          OPENSHELL_MCP_CONFORMANCE_CLIENT_IMAGE: ${{ format('openshell-mcp-conformance-client:{0}', inputs.image-tag) }}
           E2E_CMD: ${{ matrix.cmd }}
         run: |
           if [ "${{ matrix.rootless }}" = "true" ]; then

architecture/sandbox.md

@@ -49,6 +49,15 @@ paths, such as proxy support files or GPU device paths when a GPU is present.
 All ordinary agent egress is routed through the sandbox proxy. The proxy
 identifies the calling binary, checks trust-on-first-use binary identity, rejects
 unsafe internal destinations, and evaluates the active policy.
+For inspected HTTP traffic, the proxy can enforce REST method/path rules,
+WebSocket upgrade and text-message rules, GraphQL operation rules, and
+JSON-RPC method and params rules on sandbox-to-server request bodies. JSON-RPC
+request inspection buffers up to the endpoint `json_rpc.max_body_bytes` limit.
+Literal dotted keys in JSON-RPC params are accepted. If a literal key and a
+flattened nested selector path produce the same matcher key, the literal key
+takes precedence.
+JSON-RPC responses and server-to-client MCP messages on response or SSE streams
+are relayed but are not currently parsed for policy enforcement.
 
 `https://inference.local` is special. It bypasses OPA network policy and is
 handled by the inference interception path:

crates/openshell-cli/src/policy_update.rs

@@ -205,6 +205,7 @@ fn group_allow_rules(specs: &[String]) -> Result<BTreeMap<(String, u32), Vec<L7R
                     operation_type: String::new(),
                     operation_name: String::new(),
                     fields: Vec::new(),
+                    params: HashMap::default(),
                 }),
             });
     }
@@ -226,6 +227,7 @@ fn group_deny_rules(specs: &[String]) -> Result<BTreeMap<(String, u32), Vec<L7De
                 operation_type: String::new(),
                 operation_name: String::new(),
                 fields: Vec::new(),
+                params: HashMap::default(),
             });
     }
     Ok(grouped)

crates/openshell-policy/src/lib.rs

@@ -135,6 +135,8 @@ struct NetworkEndpointDef {
     graphql_persisted_queries: BTreeMap<String, GraphqlOperationDef>,
     #[serde(default, skip_serializing_if = "is_zero_u32")]
     graphql_max_body_bytes: u32,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    json_rpc: Option<JsonRpcConfigDef>,
 }
 
 // Signature dictated by serde's `skip_serializing_if`, which requires `&T`.
@@ -149,6 +151,17 @@ fn is_zero_u32(v: &u32) -> bool {
     *v == 0
 }
 
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(deny_unknown_fields)]
+struct JsonRpcConfigDef {
+    #[serde(default, skip_serializing_if = "is_zero_u32")]
+    max_body_bytes: u32,
+}
+
+fn json_rpc_config_from_proto(max_body_bytes: u32) -> Option<JsonRpcConfigDef> {
+    (max_body_bytes > 0).then_some(JsonRpcConfigDef { max_body_bytes })
+}
+
 #[derive(Debug, Serialize, Deserialize)]
 #[serde(deny_unknown_fields)]
 struct GraphqlOperationDef {
@@ -183,6 +196,8 @@ struct L7AllowDef {
     operation_name: String,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     fields: Vec<String>,
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    params: BTreeMap<String, QueryMatcherDef>,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -216,6 +231,8 @@ struct L7DenyRuleDef {
     operation_name: String,
     #[serde(default, skip_serializing_if = "Vec::is_empty")]
     fields: Vec<String>,
+    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
+    params: BTreeMap<String, QueryMatcherDef>,
 }
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -232,6 +249,24 @@ struct NetworkBinaryDef {
 // YAML → proto conversion
 // ---------------------------------------------------------------------------
 
+fn matcher_def_to_proto(matcher: QueryMatcherDef) -> L7QueryMatcher {
+    match matcher {
+        QueryMatcherDef::Glob(glob) => L7QueryMatcher { glob, any: vec![] },
+        QueryMatcherDef::Any(any) => L7QueryMatcher {
+            glob: String::new(),
+            any: any.any,
+        },
+    }
+}
+
+fn matcher_proto_to_def(matcher: L7QueryMatcher) -> QueryMatcherDef {
+    if matcher.any.is_empty() {
+        QueryMatcherDef::Glob(matcher.glob)
+    } else {
+        QueryMatcherDef::Any(QueryAnyDef { any: matcher.any })
+    }
+}
+
 fn to_proto(raw: PolicyFile) -> SandboxPolicy {
     let network_policies = raw
         .network_policies
@@ -281,16 +316,15 @@ fn to_proto(raw: PolicyFile) -> SandboxPolicy {
                                             .query
                                             .into_iter()
                                             .map(|(key, matcher)| {
-                                                let proto = match matcher {
-                                                    QueryMatcherDef::Glob(glob) => {
-                                                        L7QueryMatcher { glob, any: vec![] }
-                                                    }
-                                                    QueryMatcherDef::Any(any) => L7QueryMatcher {
-                                                        glob: String::new(),
-                                                        any: any.any,
-                                                    },
-                                                };
-                                                (key, proto)
+                                                (key, matcher_def_to_proto(matcher))
+                                            })
+                                            .collect(),
+                                        params: r
+                                            .allow
+                                            .params
+                                            .into_iter()
+                                            .map(|(key, matcher)| {
+                                                (key, matcher_def_to_proto(matcher))
                                             })
                                             .collect(),
                                     }),
@@ -310,18 +344,12 @@ fn to_proto(raw: PolicyFile) -> SandboxPolicy {
                                     query: d
                                         .query
                                         .into_iter()
-                                        .map(|(key, matcher)| {
-                                            let proto = match matcher {
-                                                QueryMatcherDef::Glob(glob) => {
-                                                    L7QueryMatcher { glob, any: vec![] }
-                                                }
-                                                QueryMatcherDef::Any(any) => L7QueryMatcher {
-                                                    glob: String::new(),
-                                                    any: any.any,
-                                                },
-                                            };
-                                            (key, proto)
-                                        })
+                                        .map(|(key, matcher)| (key, matcher_def_to_proto(matcher)))
+                                        .collect(),
+                                    params: d
+                                        .params
+                                        .into_iter()
+                                        .map(|(key, matcher)| (key, matcher_def_to_proto(matcher)))
                                         .collect(),
                                 })
                                 .collect(),
@@ -347,6 +375,10 @@ fn to_proto(raw: PolicyFile) -> SandboxPolicy {
                                 })
                                 .collect(),
                             graphql_max_body_bytes: e.graphql_max_body_bytes,
+                            json_rpc_max_body_bytes: e
+                                .json_rpc
+                                .as_ref()
+                                .map_or(0, |config| config.max_body_bytes),
                         }
                     })
                     .collect(),
@@ -452,14 +484,14 @@ fn from_proto(policy: &SandboxPolicy) -> PolicyFile {
                                                 .query
                                                 .into_iter()
                                                 .map(|(key, matcher)| {
-                                                    let yaml_matcher = if matcher.any.is_empty() {
-                                                        QueryMatcherDef::Glob(matcher.glob)
-                                                    } else {
-                                                        QueryMatcherDef::Any(QueryAnyDef {
-                                                            any: matcher.any,
-                                                        })
-                                                    };
-                                                    (key, yaml_matcher)
+                                                    (key, matcher_proto_to_def(matcher))
+                                                })
+                                                .collect(),
+                                            params: a
+                                                .params
+                                                .into_iter()
+                                                .map(|(key, matcher)| {
+                                                    (key, matcher_proto_to_def(matcher))
                                                 })
                                                 .collect(),
                                         },
@@ -481,14 +513,14 @@ fn from_proto(policy: &SandboxPolicy) -> PolicyFile {
                                         .query
                                         .iter()
                                         .map(|(key, matcher)| {
-                                            let yaml_matcher = if matcher.any.is_empty() {
-                                                QueryMatcherDef::Glob(matcher.glob.clone())
-                                            } else {
-                                                QueryMatcherDef::Any(QueryAnyDef {
-                                                    any: matcher.any.clone(),
-                                                })
-                                            };
-                                            (key.clone(), yaml_matcher)
+                                            (key.clone(), matcher_proto_to_def(matcher.clone()))
+                                        })
+                                        .collect(),
+                                    params: d
+                                        .params
+                                        .iter()
+                                        .map(|(key, matcher)| {
+                                            (key.clone(), matcher_proto_to_def(matcher.clone()))
                                         })
                                         .collect(),
                                 })
@@ -512,6 +544,7 @@ fn from_proto(policy: &SandboxPolicy) -> PolicyFile {
                                 })
                                 .collect(),
                             graphql_max_body_bytes: e.graphql_max_body_bytes,
+                            json_rpc: json_rpc_config_from_proto(e.json_rpc_max_body_bytes),
                         }
                     })
                     .collect(),
@@ -1699,6 +1732,60 @@ network_policies:
         assert_eq!(ep.deny_rules[0].fields, vec!["deleteRepository"]);
     }
 
+    #[test]
+    fn round_trip_preserves_json_rpc_max_body_bytes() {
+        let yaml = r"
+version: 1
+network_policies:
+  mcp:
+    name: mcp
+    endpoints:
+      - host: mcp.example.com
+        port: 443
+        protocol: json-rpc
+        enforcement: enforce
+        json_rpc:
+          max_body_bytes: 131072
+        rules:
+          - allow:
+              method: initialize
+    binaries:
+      - path: /usr/bin/curl
+";
+        let proto1 = parse_sandbox_policy(yaml).expect("parse failed");
+        let yaml_out = serialize_sandbox_policy(&proto1).expect("serialize failed");
+        let proto2 = parse_sandbox_policy(&yaml_out).expect("re-parse failed");
+
+        let ep = &proto2.network_policies["mcp"].endpoints[0];
+        assert_eq!(ep.protocol, "json-rpc");
+        assert_eq!(ep.json_rpc_max_body_bytes, 131_072);
+    }
+
+    #[test]
+    fn parse_rejects_unsupported_json_rpc_config_fields() {
+        let yaml = r"
+version: 1
+network_policies:
+  mcp:
+    endpoints:
+      - host: mcp.example.com
+        port: 443
+        protocol: json-rpc
+        json_rpc:
+          max_body_bytes: 131072
+          on_parse_error: deny
+          batch_policy: all
+        access: full
+    binaries:
+      - path: /usr/bin/curl
+";
+
+        assert!(
+            parse_sandbox_policy(yaml).is_err(),
+            "unsupported json_rpc fields must not be silently accepted"
+        );
+    }
+
     #[test]
     fn round_trip_preserves_websocket_credential_rewrite() {
         let yaml = r"

crates/openshell-policy/src/merge.rs

@@ -747,6 +747,7 @@ fn expand_access_preset(protocol: &str, access: &str) -> Option<Vec<L7Rule>> {
                     operation_type: String::new(),
                     operation_name: String::new(),
                     fields: Vec::new(),
+                    params: HashMap::default(),
                 }),
             })
             .collect(),
@@ -961,6 +962,7 @@ mod tests {
                 operation_type: String::new(),
                 operation_name: String::new(),
                 fields: Vec::new(),
+                params: HashMap::default(),
             }),
         }
     }

crates/openshell-providers/src/profiles.rs

@@ -201,6 +201,8 @@ pub struct EndpointProfile {
     pub graphql_persisted_queries: HashMap<String, GraphqlOperationProfile>,
     #[serde(default, skip_serializing_if = "is_zero")]
     pub graphql_max_body_bytes: u32,
+    #[serde(default, skip_serializing_if = "is_zero")]
+    pub json_rpc_max_body_bytes: u32,
     #[serde(default, skip_serializing_if = "String::is_empty")]
     pub path: String,
 }
@@ -744,6 +746,7 @@ fn endpoint_to_proto(endpoint: &EndpointProfile) -> NetworkEndpoint {
             .map(|(name, operation)| (name.clone(), graphql_operation_to_proto(operation)))
             .collect(),
         graphql_max_body_bytes: endpoint.graphql_max_body_bytes,
+        json_rpc_max_body_bytes: endpoint.json_rpc_max_body_bytes,
         path: endpoint.path.clone(),
     }
 }
@@ -774,6 +777,7 @@ fn endpoint_from_proto(endpoint: &NetworkEndpoint) -> EndpointProfile {
             .map(|(name, operation)| (name.clone(), graphql_operation_from_proto(operation)))
             .collect(),
         graphql_max_body_bytes: endpoint.graphql_max_body_bytes,
+        json_rpc_max_body_bytes: endpoint.json_rpc_max_body_bytes,
         path: endpoint.path.clone(),
     }
 }
@@ -817,6 +821,7 @@ fn allow_to_proto(allow: &L7AllowProfile) -> L7Allow {
         operation_type: allow.operation_type.clone(),
         operation_name: allow.operation_name.clone(),
         fields: allow.fields.clone(),
+        params: HashMap::new(),
     }
 }
 
@@ -849,6 +854,7 @@ fn deny_rule_to_proto(rule: &L7DenyRuleProfile) -> L7DenyRule {
         operation_type: rule.operation_type.clone(),
         operation_name: rule.operation_name.clone(),
         fields: rule.fields.clone(),
+        params: HashMap::new(),
     }
 }
 

crates/openshell-sandbox/src/mechanistic_mapper.rs

@@ -355,6 +355,7 @@ fn build_l7_rules(samples: &HashMap<(String, String), u32>) -> Vec<L7Rule> {
                 operation_type: String::new(),
                 operation_name: String::new(),
                 fields: Vec::new(),
+                params: HashMap::new(),
             }),
         });
     }