diff --git a/plugin/index.ts b/plugin/index.ts
index 7f8ce75..2c2f727 100644
--- a/plugin/index.ts
+++ b/plugin/index.ts
@@ -69,30 +69,29 @@ function extractUntrustedConversationInfo(text: string): Record<string, unknown>
   }
 }
 
-function deriveDecisionInputFromAgentCtx(
-  ctx: Record<string, unknown>,
-): { channel: string; channelId?: string; senderId?: string; content: string } {
-  const channel = normalizeChannel(ctx);
-  const content = typeof ctx.input === "string" ? ctx.input : "";
-  const conv = extractUntrustedConversationInfo(content) || {};
-  const channelIdRaw =
-    (typeof ctx.channelId === "string" && ctx.channelId) ||
+function deriveDecisionInputFromPrompt(
+  prompt: string,
+  messageProvider?: string,
+): {
+  channel: string;
+  channelId?: string;
+  senderId?: string;
+  content: string;
+  conv: Record<string, unknown>;
+} {
+  const conv = extractUntrustedConversationInfo(prompt) || {};
+  const channel = (messageProvider || "").toLowerCase();
+  const channelId =
     (typeof conv.channel_id === "string" && conv.channel_id) ||
     (typeof conv.chat_id === "string" && conv.chat_id.startsWith("channel:")
       ? conv.chat_id.slice("channel:".length)
       : undefined);
-  const senderIdRaw =
-    (typeof ctx.senderId === "string" && ctx.senderId) ||
+  const senderId =
     (typeof conv.sender_id === "string" && conv.sender_id) ||
     (typeof conv.sender === "string" && conv.sender) ||
     undefined;
 
-  return {
-    channel,
-    channelId: channelIdRaw,
-    senderId: senderIdRaw,
-    content,
-  };
+  return { channel, channelId, senderId, content: prompt, conv };
 }
 
 function pruneDecisionMap(now = Date.now()) {
@@ -363,41 +362,32 @@ export default {
       const live = getLivePluginConfig(api, baseConfig as WhisperGateConfig) as WhisperGateConfig & DebugConfig;
       ensurePolicyStateLoaded(api, live);
 
-      // In before_model_resolve, ctx only has: agentId, sessionKey, sessionId, workspaceDir, messageProvider.
-      // senderId/channelId/input are NOT available. Use event.prompt (user message incl. untrusted metadata).
-      const channel = (ctx.messageProvider || "").toLowerCase();
-      if (live.discordOnly !== false && channel !== "discord") return;
-
       const prompt = ((event as Record<string, unknown>).prompt as string) || "";
-      const conv = extractUntrustedConversationInfo(prompt) || {};
-      const senderId =
-        (typeof conv.sender_id === "string" && conv.sender_id) ||
-        (typeof conv.sender === "string" && conv.sender) ||
-        undefined;
-      const channelId =
-        (typeof conv.channel_id === "string" && conv.channel_id) ||
-        (typeof (conv as Record<string, unknown>).conversation_label === "string"
-          ? undefined
-          : undefined);
+      const derived = deriveDecisionInputFromPrompt(prompt, ctx.messageProvider);
+      if (live.discordOnly !== false && derived.channel !== "discord") return;
 
       let rec = sessionDecision.get(key);
       if (!rec || Date.now() - rec.createdAt > DECISION_TTL_MS) {
         if (rec) sessionDecision.delete(key);
         const decision = evaluateDecision({
           config: live,
-          channel,
-          channelId,
+          channel: derived.channel,
+          channelId: derived.channelId,
           channelPolicies: policyState.channelPolicies,
-          senderId,
-          content: prompt,
+          senderId: derived.senderId,
+          content: derived.content,
         });
         rec = { decision, createdAt: Date.now() };
         sessionDecision.set(key, rec);
         pruneDecisionMap();
-        if (shouldDebugLog(live, channelId)) {
+        if (shouldDebugLog(live, derived.channelId)) {
           api.logger.info(
-            `whispergate: debug before_model_resolve recompute session=${key} senderId=${senderId} decision=${decision.reason} ` +
-              `shouldNoReply=${decision.shouldUseNoReply} shouldInject=${decision.shouldInjectEndMarkerPrompt}`,
+            `whispergate: debug before_model_resolve recompute session=${key} ` +
+              `channel=${derived.channel} channelId=${derived.channelId ?? ""} senderId=${derived.senderId ?? ""} ` +
+              `convSenderId=${String((derived.conv as Record<string, unknown>).sender_id ?? "")} ` +
+              `convSender=${String((derived.conv as Record<string, unknown>).sender ?? "")} ` +
+              `convChannelId=${String((derived.conv as Record<string, unknown>).channel_id ?? "")} ` +
+              `decision=${decision.reason} shouldNoReply=${decision.shouldUseNoReply} shouldInject=${decision.shouldInjectEndMarkerPrompt}`,
           );
         }
       }
@@ -425,31 +415,26 @@ export default {
       if (!rec || Date.now() - rec.createdAt > DECISION_TTL_MS) {
         if (rec) sessionDecision.delete(key);
 
-        // before_prompt_build has event.prompt and event.messages available.
-        const channel = (ctx.messageProvider || "").toLowerCase();
         const prompt = ((event as Record<string, unknown>).prompt as string) || "";
-        const conv = extractUntrustedConversationInfo(prompt) || {};
-        const senderId =
-          (typeof conv.sender_id === "string" && conv.sender_id) ||
-          (typeof conv.sender === "string" && conv.sender) ||
-          undefined;
-        const channelId =
-          (typeof conv.channel_id === "string" && conv.channel_id) ||
-          undefined;
+        const derived = deriveDecisionInputFromPrompt(prompt, ctx.messageProvider);
 
         const decision = evaluateDecision({
           config: live,
-          channel,
-          channelId,
+          channel: derived.channel,
+          channelId: derived.channelId,
           channelPolicies: policyState.channelPolicies,
-          senderId,
-          content: prompt,
+          senderId: derived.senderId,
+          content: derived.content,
         });
         rec = { decision, createdAt: Date.now() };
-        if (shouldDebugLog(live, channelId)) {
+        if (shouldDebugLog(live, derived.channelId)) {
           api.logger.info(
-            `whispergate: debug before_prompt_build recompute session=${key} senderId=${senderId} decision=${decision.reason} ` +
-              `shouldNoReply=${decision.shouldUseNoReply} shouldInject=${decision.shouldInjectEndMarkerPrompt}`,
+            `whispergate: debug before_prompt_build recompute session=${key} ` +
+              `channel=${derived.channel} channelId=${derived.channelId ?? ""} senderId=${derived.senderId ?? ""} ` +
+              `convSenderId=${String((derived.conv as Record<string, unknown>).sender_id ?? "")} ` +
+              `convSender=${String((derived.conv as Record<string, unknown>).sender ?? "")} ` +
+              `convChannelId=${String((derived.conv as Record<string, unknown>).channel_id ?? "")} ` +
+              `decision=${decision.reason} shouldNoReply=${decision.shouldUseNoReply} shouldInject=${decision.shouldInjectEndMarkerPrompt}`,
           );
         }
       }