(MOT-3868) fix(harness): publish typed request schema for harness::react

harness/src/functions/mod.rs

@@ -214,7 +214,7 @@ pub fn register_all(iii: &Arc<IIIClient>, deps: &Arc<Deps>) {
         deps,
         react::REACT_ID,
         react::REACT_DESC,
-        |d, ev: Value, meta| async move { react::handle(&d, ev, meta).await },
+        |d, ev: react::ReactEvent, meta| async move { react::handle(&d, ev.0, meta).await },
     );
 
     tracing::info!("all harness::* functions registered");

harness/src/functions/react.rs

@@ -52,6 +52,50 @@ pub const REACT_DESC: &str =
      events and callbacks: bind it via engine::register_trigger with the sub-agent spec in \
      `metadata`.";
 
+/// Fired-event payload of a reactive subscription: arbitrary JSON produced by
+/// the originating trigger, then appended to the spawned sub-agent task.
+///
+/// The handler keeps a lossless `serde_json::Value` payload internally because
+/// trigger events are not always objects. This wrapper exists so registration
+/// publishes a real schema instead of `AnyValue`, which the registry publish
+/// gate rejects.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(transparent)]
+pub struct ReactEvent(pub Value);
+
+impl JsonSchema for ReactEvent {
+    fn schema_name() -> String {
+        "ReactEvent".to_string()
+    }
+
+    fn json_schema(_: &mut schemars::r#gen::SchemaGenerator) -> schemars::schema::Schema {
+        use schemars::schema::{InstanceType, Metadata, SchemaObject};
+        SchemaObject {
+            instance_type: Some(
+                vec![
+                    InstanceType::Null,
+                    InstanceType::Boolean,
+                    InstanceType::Number,
+                    InstanceType::String,
+                    InstanceType::Array,
+                    InstanceType::Object,
+                ]
+                .into(),
+            ),
+            metadata: Some(Box::new(Metadata {
+                description: Some(
+                    "Arbitrary fired-event payload from the subscribed trigger; appended to the \
+                     spawned sub-agent task."
+                        .to_string(),
+                ),
+                ..Default::default()
+            })),
+            ..Default::default()
+        }
+        .into()
+    }
+}
+
 /// iii-state scope holding join accumulator records (one key per `join.id`).
 const JOIN_SCOPE: &str = "harness::react_join";
 

harness/src/surface.rs

@@ -6,9 +6,11 @@
 //! `harness::on-config-change`) are intentionally excluded — they are not part
 //! of the agent-facing surface.
 
+use crate::functions::react::REACT_ID;
 use crate::functions::{
     function_resolve::{FunctionResolveRequest, FunctionResolveResponse},
     function_trigger::{FunctionTriggerRequest, FunctionTriggerResponse},
+    react::{ReactEvent, ReactResult},
     send::{SendRequest, SendResponse},
     spawn::{SpawnRequest, SpawnResponse},
     status::{StatusReport, StatusRequest},
@@ -62,5 +64,6 @@ pub fn catalog() -> Vec<FunctionSpec> {
         spec::<FunctionResolveRequest, FunctionResolveResponse>(FUNCTION_RESOLVE_ID),
         spec::<StopRequest, StopResponse>(STOP_ID),
         spec::<StatusRequest, Option<StatusReport>>(STATUS_ID),
+        spec::<ReactEvent, ReactResult>(REACT_ID),
     ]
 }

harness/tests/golden/schemas/harness.react.json

@@ -0,0 +1,44 @@
+{
+  "function_id": "harness::react",
+  "request_schema": {
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "description": "Arbitrary fired-event payload from the subscribed trigger; appended to the spawned sub-agent task.",
+    "title": "ReactEvent",
+    "type": [
+      "null",
+      "boolean",
+      "number",
+      "string",
+      "array",
+      "object"
+    ]
+  },
+  "response_schema": {
+    "$schema": "http://json-schema.org/draft-07/schema#",
+    "properties": {
+      "child_session_id": {
+        "description": "The spawned sub-agent's child session id, when spawn returned one.",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "note": {
+        "description": "Why nothing spawned (missing spec, join not yet complete, already fired, error). Present iff `!spawned`.",
+        "type": [
+          "string",
+          "null"
+        ]
+      },
+      "spawned": {
+        "description": "Whether a `harness::spawn` was dispatched this call.",
+        "type": "boolean"
+      }
+    },
+    "required": [
+      "spawned"
+    ],
+    "title": "ReactResult",
+    "type": "object"
+  }
+}

harness/tests/schemas.rs

@@ -40,6 +40,7 @@ fn catalog_lists_all_functions_in_registration_order() {
             "harness::function::resolve",
             "harness::stop",
             "harness::status",
+            "harness::react",
         ]
     );
 }