systemMessageComposition experimental configuration for more control over constructed system message

core/config/load.ts

@@ -369,7 +369,7 @@ async function intermediateToFinalConfig(
               ideSettings,
               writeLog,
               config.completionOptions,
-              config.systemMessage,
+              config.systemMessage
             );
 
             if (llm?.providerName === "free-trial") {
@@ -397,8 +397,8 @@ async function intermediateToFinalConfig(
       (config.contextProviders || [])
         .filter(isContextProviderWithParams)
         .find((cp) => cp.name === "codebase") as
-        | ContextProviderWithParams
-        | undefined
+      | ContextProviderWithParams
+      | undefined
     )?.params || {};
 
   const DEFAULT_CONTEXT_PROVIDERS = [
@@ -991,5 +991,6 @@ export {
   finalToBrowserConfig,
   intermediateToFinalConfig,
   loadContinueConfigFromJson,
-  type BrowserSerializedContinueConfig,
+  type BrowserSerializedContinueConfig
 };
+

core/config/types.ts

@@ -1047,6 +1047,7 @@ declare global {
     useChromiumForDocsCrawling?: boolean;
     useTools?: boolean;
     modelContextProtocolServers?: MCPOptions[];
+    systemMessageComposition?: "legacy" | "append" | "prepend" | "placeholders";
   }
 
   interface AnalyticsConfig {

core/index.d.ts

@@ -43,13 +43,13 @@ export interface IndexingProgressUpdate {
   desc: string;
   shouldClearIndexes?: boolean;
   status:
-    | "loading"
-    | "indexing"
-    | "done"
-    | "failed"
-    | "paused"
-    | "disabled"
-    | "cancelled";
+  | "loading"
+  | "indexing"
+  | "done"
+  | "failed"
+  | "paused"
+  | "disabled"
+  | "cancelled";
   debugInfo?: string;
 }
 
@@ -675,10 +675,10 @@ export interface IDE {
   getCurrentFile(): Promise<
     | undefined
     | {
-        isUntitled: boolean;
-        path: string;
-        contents: string;
-      }
+      isUntitled: boolean;
+      path: string;
+      contents: string;
+    }
   >;
 
   getLastFileSaveTimestamp?(): number;
@@ -862,11 +862,11 @@ export interface CustomCommand {
 export interface Prediction {
   type: "content";
   content:
-    | string
-    | {
-        type: "text";
-        text: string;
-      }[];
+  | string
+  | {
+    type: "text";
+    text: string;
+  }[];
 }
 
 export interface ToolExtras {
@@ -1134,6 +1134,7 @@ export interface ExperimentalConfig {
    */
   useChromiumForDocsCrawling?: boolean;
   modelContextProtocolServers?: MCPOptions[];
+  systemMessageComposition?: "legacy" | "append" | "prepend" | "placeholders";
 }
 
 export interface AnalyticsConfig {
@@ -1204,9 +1205,9 @@ export interface Config {
   embeddingsProvider?: EmbeddingsProviderDescription | ILLM;
   /** The model that Continue will use for tab autocompletions. */
   tabAutocompleteModel?:
-    | CustomLLM
-    | ModelDescription
-    | (CustomLLM | ModelDescription)[];
+  | CustomLLM
+  | ModelDescription
+  | (CustomLLM | ModelDescription)[];
   /** Options for tab autocomplete */
   tabAutocompleteOptions?: Partial<TabAutocompleteOptions>;
   /** UI styles customization */
@@ -1298,9 +1299,9 @@ export type PackageDetailsSuccess = PackageDetails & {
 export type PackageDocsResult = {
   packageInfo: ParsedPackageInfo;
 } & (
-  | { error: string; details?: never }
-  | { details: PackageDetailsSuccess; error?: never }
-);
+    | { error: string; details?: never }
+    | { details: PackageDetailsSuccess; error?: never }
+  );
 
 export interface TerminalOptions {
   reuseTerminal?: boolean;

core/llm/constructMessages.ts

@@ -1,4 +1,5 @@
 import {
+  BrowserSerializedContinueConfig,
   ChatHistoryItem,
   ChatMessage,
   MessagePart,
@@ -11,15 +12,158 @@ import { modelSupportsTools } from "./autodetect";
 const TOOL_USE_RULES = `When using tools, follow the following guidelines:
 - Avoid calling tools unless they are absolutely necessary. For example, if you are asked a simple programming question you do not need web search. As another example, if the user asks you to explain something about code, do not create a new file.`;
 
+const CODE_BLOCK_INSTRUCTIONS = "Always include the language and file name in the info string when you write code blocks, for example '```python file.py'."
+
+// Helper function to strip whitespace
+function stripWhitespace(text: string, stripLeading = false, stripTrailing = false): string {
+  let result = text;
+  if (stripLeading) {
+    result = result.replace(/^[\s\n]+/, '');
+  }
+  if (stripTrailing) {
+    result = result.replace(/[\s\n]+$/, '');
+  }
+  return result;
+}
+
+// Helper function for placeholder replacement with whitespace handling
+function replacePlaceholder(
+  text: string,
+  placeholder: string,
+  replacement: string
+): string {
+  if (!text.includes(placeholder)) {
+    return text;
+  }
+
+  const placeholderIndex = text.indexOf(placeholder);
+  const placeholderLength = placeholder.length;
+
+  // Check surroundings to determine whitespace needs
+  const isAtBeginning = placeholderIndex === 0;
+  const isAtEnd = placeholderIndex + placeholderLength === text.length;
+
+  if (!replacement) {
+    // No replacement to add - just replace with empty string and clean up
+    let processed = text.replace(placeholder, "");
+    return stripWhitespace(processed, isAtBeginning, isAtEnd);
+  } else {
+    // Add replacement with appropriate whitespace
+    let formattedReplacement = replacement;
+
+    if (!isAtBeginning && !(/[\n\s]$/.test(text.substring(0, placeholderIndex)))) {
+      formattedReplacement = "\n\n" + formattedReplacement;
+    };
+
+    if (!isAtEnd && !(/^[\n\s]/.test(text.substring(placeholderIndex + placeholderLength)))) {
+      formattedReplacement = formattedReplacement + "\n\n";
+    };
+
+    return text.replace(placeholder, formattedReplacement);
+  }
+}
+
 function constructSystemPrompt(
   modelDescription: ModelDescription,
   useTools: boolean,
+  continueConfig: BrowserSerializedContinueConfig
 ): string | null {
-  let systemMessage =
-    "Always include the language and file name in the info string when you write code blocks, for example '```python file.py'.";
-  if (useTools && modelSupportsTools(modelDescription)) {
-    systemMessage += "\n\n" + TOOL_USE_RULES;
+
+  let systemMessage = "";
+  // We we have no access to the LLM class, we final systemMessage have to be the same as in core/llm/index.ts
+  const userSystemMessage = modelDescription.systemMessage ?? continueConfig.systemMessage;
+
+  // Get templates from model description or use defaults
+  const codeBlockTemplate = modelDescription.promptTemplates?.codeBlockInstructions ?? CODE_BLOCK_INSTRUCTIONS;
+
+  const toolUseTemplate = modelDescription.promptTemplates?.toolUseRules ?? TOOL_USE_RULES;
+
+  // Determine which instructions to include
+  const codeBlockInstructions = codeBlockTemplate;
+  const toolUseInstructions = useTools && modelSupportsTools(modelDescription) ? toolUseTemplate : "";
+
+  switch ((continueConfig.experimental?.systemMessageComposition || "legacy")) {
+    case "prepend":
+      // Put user system message first, then default instructions
+      systemMessage = userSystemMessage || "";
+
+      if (systemMessage && codeBlockInstructions) {
+        systemMessage += "\n\n" + codeBlockInstructions;
+      } else if (codeBlockInstructions) {
+        systemMessage = codeBlockInstructions;
+      }
+
+      if (systemMessage && toolUseInstructions) {
+        systemMessage += "\n\n" + toolUseInstructions;
+      } else if (toolUseInstructions) {
+        systemMessage = toolUseInstructions;
+      }
+      break;
+
+    case "placeholders":
+    case "placeholders":
+      if (userSystemMessage) {
+        // Define placeholders
+        const allDefaultInstructions = [
+          codeBlockInstructions,
+          toolUseInstructions
+        ].filter(Boolean).join("\n\n");
+
+        // Replace placeholders in user system message
+        let processedMessage = userSystemMessage;
+
+        // Replace all placeholders using our helper function
+        processedMessage = replacePlaceholder(
+          processedMessage,
+          "{DEFAULT_INSTRUCTIONS}",
+          allDefaultInstructions
+        );
+
+        processedMessage = replacePlaceholder(
+          processedMessage,
+          "{CODE_BLOCK_INSTRUCTIONS}",
+          codeBlockInstructions
+        );
+
+        processedMessage = replacePlaceholder(
+          processedMessage,
+          "{TOOL_USE_RULES}",
+          toolUseInstructions
+        );
+
+        systemMessage = processedMessage;
+      } else {
+        // Fall back to legacy behavior if no user system message
+        systemMessage = codeBlockInstructions;
+        if (toolUseInstructions) {
+          systemMessage += "\n\n" + toolUseInstructions;
+        }
+      }
+      break;
+
+
+    case "legacy":
+    case "append":
+    default:
+      systemMessage = codeBlockInstructions;
+      if (useTools && modelSupportsTools(modelDescription)) {
+        systemMessage += "\n\n" + toolUseTemplate;
+      }
+      // logic moved from core/llm/countTokens.ts
+      if (userSystemMessage && userSystemMessage.trim() !== "") {
+        const shouldAddNewLines = systemMessage !== "";
+        if (shouldAddNewLines) {
+          systemMessage += "\n\n";
+        }
+        systemMessage += userSystemMessage;
+      }
+      if (userSystemMessage === "") {
+        // Used defined explicit empty system message will be forced
+        systemMessage = "";
+      }
+      break;
   }
+
   return systemMessage;
 }
 
@@ -30,13 +174,14 @@ export function constructMessages(
   history: ChatHistoryItem[],
   modelDescription: ModelDescription,
   useTools: boolean,
+  continueConfig: BrowserSerializedContinueConfig,
 ): ChatMessage[] {
   const filteredHistory = history.filter(
     (item) => item.message.role !== "system",
   );
   const msgs: ChatMessage[] = [];
 
-  const systemMessage = constructSystemPrompt(modelDescription, useTools);
+  const systemMessage = constructSystemPrompt(modelDescription, useTools, continueConfig);
   if (systemMessage) {
     msgs.push({
       role: "system",

core/llm/countTokens.ts

@@ -27,9 +27,9 @@ class LlamaEncoding implements Encoding {
 }
 
 class NonWorkerAsyncEncoder implements AsyncEncoder {
-  constructor(private readonly encoding: Encoding) {}
+  constructor(private readonly encoding: Encoding) { }
 
-  async close(): Promise<void> {}
+  async close(): Promise<void> { }
 
   async encode(text: string): Promise<number[]> {
     return this.encoding.encode(text);
@@ -383,8 +383,8 @@ function compileChatMessages(
 ): ChatMessage[] {
   let msgsCopy = msgs
     ? msgs
-        .map((msg) => ({ ...msg }))
-        .filter((msg) => !chatMessageIsEmpty(msg) && msg.role !== "system")
+      .map((msg) => ({ ...msg }))
+      .filter((msg) => !chatMessageIsEmpty(msg) && msg.role !== "system")
     : [];
 
   msgsCopy = addSpaceToAnyEmptyMessages(msgsCopy);
@@ -397,6 +397,7 @@ function compileChatMessages(
     msgsCopy.push(promptMsg);
   }
 
+  /* Original logic, moved to core/llm/constructMessages.ts
   if (
     (systemMessage && systemMessage.trim() !== "") ||
     msgs?.[0]?.role === "system"
@@ -419,6 +420,29 @@ function compileChatMessages(
     // Insert as second to last
     // Later moved to top, but want second-priority to last user message
     msgsCopy.splice(-1, 0, systemChatMsg);
+  }*/
+
+  if (
+    msgs?.[0]?.role === "system"
+  ) {
+    let content = "";
+
+    content = renderChatMessage(msgs?.[0]);
+
+    const systemChatMsg: ChatMessage = {
+      role: "system",
+      content,
+    };
+    // Insert as second to last
+    // Later moved to top, but want second-priority to last user message
+    msgsCopy.splice(-1, 0, systemChatMsg);
+  } else if (systemMessage && systemMessage.trim() !== "") {
+    // In case core/llm/constructMessages.ts constructSystemPrompt() is not called
+    const systemChatMsg: ChatMessage = {
+      role: "system",
+      content: systemMessage,
+    };
+    msgsCopy.splice(-1, 0, systemChatMsg);
   }
 
   let functionTokens = 0;
@@ -469,5 +493,6 @@ export {
   pruneLinesFromTop,
   pruneRawPromptFromTop,
   pruneStringFromBottom,
-  pruneStringFromTop,
+  pruneStringFromTop
 };
+