refactor: always use assistant+tool injection, skip for GitHub Copilot when last message is user role

Author: Tarquinen

lib/messages/inject.ts

@@ -7,7 +7,6 @@ import {
     extractParameterKey,
     buildToolIdList,
     createSyntheticAssistantMessageWithToolPart,
-    createSyntheticUserMessage,
 } from "./utils"
 import { getFilePathFromParameters, isProtectedFilePath } from "../protected-file-patterns"
 import { getLastUserMessage } from "../shared-utils"
@@ -143,22 +142,15 @@ export const insertPruneToolContext = (
     const isGitHubCopilot =
         providerID === "github-copilot" || providerID === "github-copilot-enterprise"
 
-    logger.info("Injecting prunable-tools list", {
-        providerID,
-        isGitHubCopilot,
-        injectionType: isGitHubCopilot ? "assistant-with-tool-part" : "user-message",
-    })
-
-    const variant = state.variant ?? (lastUserMessage.info as UserMessage).variant
     if (isGitHubCopilot) {
-        messages.push(
-            createSyntheticAssistantMessageWithToolPart(
-                lastUserMessage,
-                prunableToolsContent,
-                variant,
-            ),
-        )
-    } else {
-        messages.push(createSyntheticUserMessage(lastUserMessage, prunableToolsContent, variant))
+        const lastMessage = messages[messages.length - 1]
+        if (lastMessage?.info?.role === "user") {
+            return
+        }
     }
+
+    const variant = state.variant ?? userInfo.variant
+    messages.push(
+        createSyntheticAssistantMessageWithToolPart(lastUserMessage, prunableToolsContent, variant),
+    )
 }

lib/messages/utils.ts

@@ -7,37 +7,6 @@ const SYNTHETIC_MESSAGE_ID = "msg_01234567890123456789012345"
 const SYNTHETIC_PART_ID = "prt_01234567890123456789012345"
 const SYNTHETIC_CALL_ID = "call_01234567890123456789012345"
 
-export const createSyntheticUserMessage = (
-    baseMessage: WithParts,
-    content: string,
-    variant?: string,
-): WithParts => {
-    const userInfo = baseMessage.info as UserMessage
-    return {
-        info: {
-            id: SYNTHETIC_MESSAGE_ID,
-            sessionID: userInfo.sessionID,
-            role: "user",
-            time: { created: Date.now() },
-            agent: userInfo.agent || "code",
-            model: {
-                providerID: userInfo.model.providerID,
-                modelID: userInfo.model.modelID,
-            },
-            ...(variant !== undefined && { variant }),
-        },
-        parts: [
-            {
-                id: SYNTHETIC_PART_ID,
-                sessionID: userInfo.sessionID,
-                messageID: SYNTHETIC_MESSAGE_ID,
-                type: "text",
-                text: content,
-            },
-        ],
-    }
-}
-
 export const createSyntheticAssistantMessageWithToolPart = (
     baseMessage: WithParts,
     content: string,