feat(opencode-go): muse-spark-1.2 and Responses tool fixes (#3820)

- Add muse-spark-1.2-contributor as responses-only model on OpenCode Go
- Normalize object tool schemas without properties in OpenCode Go executor
- Make fallback Responses call_ids unique across same-millisecond calls
- Make Responses output coercion fail-soft for circular and non-stringifiable values

open-sse/executors/opencode-go.js

@@ -61,9 +61,12 @@ function normalizeResponsesTools(body) {
     const name = rawName.trim();
     if (!name) return false;
     const description = typeof tool.description === "string" ? tool.description : (typeof fn?.description === "string" ? fn.description : "");
-    const parameters = (tool.parameters && typeof tool.parameters === "object" && !Array.isArray(tool.parameters))
+    let parameters = (tool.parameters && typeof tool.parameters === "object" && !Array.isArray(tool.parameters))
       ? tool.parameters
       : (fn?.parameters && typeof fn.parameters === "object" && !Array.isArray(fn.parameters) ? fn.parameters : { type: "object", properties: {} });
+    // Mirror the request translator: {type:"object"} without properties is rejected
+    // by strict Responses backends, so fill in the empty properties map.
+    if (parameters.type === "object" && !parameters.properties) parameters = { ...parameters, properties: {} };
     for (const k of Object.keys(tool)) delete tool[k];
     tool.type = "function";
     tool.name = name.slice(0, MAX_TOOL_NAME_LEN);

open-sse/providers/registry/opencode-go.js

@@ -52,6 +52,7 @@ export default {
     { id: "qwen3.6-plus", name: "Qwen 3.6 Plus", supportedFormats: ["openai", "claude"] },
     // Muse Spark is served by /zen/go/v1/responses only — responses-only entry forces
     // chatCore past the sourceFormat-matched transports into translation (see chatCore guard).
+    { id: "muse-spark-1.2-contributor", name: "Muse Spark 1.2 Contributor", targetFormat: "openai-responses", supportedFormats: ["openai-responses"] },
     { id: "muse-spark-1.3-contributor", name: "Muse Spark 1.3 Contributor", targetFormat: "openai-responses", supportedFormats: ["openai-responses"] },
   ],
   features: {

open-sse/translator/formats/responsesApi.js

@@ -26,8 +26,13 @@ export function normalizeResponsesInput(input) {
 // Strict Responses upstreams reject overlong call_ids with InputValidationError (#393).
 export const MAX_RESPONSES_CALL_ID_LEN = 64;
 
+// Fallback ids share one Date.now() when a batch of items is sanitized in a tight
+// loop — a per-process sequence keeps same-millisecond ids unique so
+// function_call ↔ function_call_output correlation never collides.
+let responsesCallIdSeq = 0;
+
 export function clampResponsesCallId(id) {
-  if (typeof id !== "string" || !id) return `call_${Date.now()}`;
+  if (typeof id !== "string" || !id) return `call_${Date.now()}_${(responsesCallIdSeq += 1)}`;
   return id.length > MAX_RESPONSES_CALL_ID_LEN ? id.substring(0, MAX_RESPONSES_CALL_ID_LEN) : id;
 }
 
@@ -55,7 +60,15 @@ export function coerceResponsesArguments(value) {
 export function coerceResponsesOutput(value) {
   if (typeof value === "string") return value;
   if (value === undefined || value === null) return "";
-  if (Array.isArray(value)) return value.map((c) => c?.text ?? JSON.stringify(c)).join("");
+  if (Array.isArray(value)) {
+    return value.map((c) => {
+      try {
+        return c?.text ?? JSON.stringify(c);
+      } catch {
+        return String(c);
+      }
+    }).join("");
+  }
   try {
     return JSON.stringify(value);
   } catch {