Load conversation history into new agent session system prompts

Update pnpm-lock.yaml

lint

Author: charlesvien

apps/twig/src/main/services/agent/schemas.ts

@@ -13,6 +13,24 @@ export const credentialsSchema = z.object({
 
 export type Credentials = z.infer<typeof credentialsSchema>;
 
+// Content block schema (shared across prompt input and conversation history)
+export const contentBlockSchema = z
+  .object({
+    type: z.string(),
+    text: z.string().optional(),
+    _meta: z.record(z.string(), z.unknown()).nullish(),
+  })
+  .passthrough();
+
+export const conversationHistoryTurnSchema = z.object({
+  role: z.enum(["user", "assistant"]),
+  content: z.array(contentBlockSchema),
+});
+
+export type ConversationHistoryTurn = z.infer<
+  typeof conversationHistoryTurnSchema
+>;
+
 // Session config schema
 export const sessionConfigSchema = z.object({
   taskId: z.string(),
@@ -27,6 +45,8 @@ export const sessionConfigSchema = z.object({
   additionalDirectories: z.array(z.string()).optional(),
   /** Permission mode to use for the session (e.g. "default", "acceptEdits", "plan", "bypassPermissions") */
   permissionMode: z.string().optional(),
+  /** Conversation history to inject into the system prompt for new sessions */
+  conversationHistory: z.array(conversationHistoryTurnSchema).optional(),
 });
 
 export type SessionConfig = z.infer<typeof sessionConfigSchema>;
@@ -45,6 +65,7 @@ export const startSessionInput = z.object({
   runMode: z.enum(["local", "cloud"]).optional(),
   adapter: z.enum(["claude", "codex"]).optional(),
   additionalDirectories: z.array(z.string()).optional(),
+  conversationHistory: z.array(conversationHistoryTurnSchema).optional(),
 });
 
 export type StartSessionInput = z.infer<typeof startSessionInput>;
@@ -102,14 +123,6 @@ export const sessionResponseSchema = z.object({
 export type SessionResponse = z.infer<typeof sessionResponseSchema>;
 
 // Prompt input/output
-export const contentBlockSchema = z
-  .object({
-    type: z.string(),
-    text: z.string().optional(),
-    _meta: z.record(z.string(), z.unknown()).nullish(),
-  })
-  .passthrough();
-
 export const promptInput = z.object({
   sessionId: z.string(),
   prompt: z.array(contentBlockSchema),
@@ -160,6 +173,7 @@ export const reconnectSessionInput = z.object({
   /** Additional directories Claude can access beyond cwd (for worktree support) */
   additionalDirectories: z.array(z.string()).optional(),
   permissionMode: z.string().optional(),
+  conversationHistory: z.array(conversationHistoryTurnSchema).optional(),
 });
 
 export type ReconnectSessionInput = z.infer<typeof reconnectSessionInput>;

apps/twig/src/main/services/agent/service.ts

@@ -33,6 +33,7 @@ import type { SleepService } from "../sleep/service.js";
 import {
   AgentServiceEvent,
   type AgentServiceEvents,
+  type ConversationHistoryTurn,
   type Credentials,
   type InterruptReason,
   type PromptOutput,
@@ -178,6 +179,8 @@ interface SessionConfig {
   additionalDirectories?: string[];
   /** Permission mode to use for the session */
   permissionMode?: string;
+  /** Conversation history to inject into the system prompt for new sessions */
+  conversationHistory?: ConversationHistoryTurn[];
 }
 
 interface ManagedSession {
@@ -423,6 +426,7 @@ export class AgentService extends TypedEventEmitter<AgentServiceEvents> {
       adapter,
       additionalDirectories,
       permissionMode,
+      conversationHistory,
     } = config;
 
     if (!isRetry) {
@@ -599,6 +603,7 @@ export class AgentService extends TypedEventEmitter<AgentServiceEvents> {
               taskRunId,
               systemPrompt,
               ...(permissionMode && { permissionMode }),
+              ...(conversationHistory?.length && { conversationHistory }),
               ...(additionalDirectories?.length && {
                 claudeCode: {
                   options: { additionalDirectories },
@@ -1320,6 +1325,10 @@ For git operations while detached:
           : undefined,
       permissionMode:
         "permissionMode" in params ? params.permissionMode : undefined,
+      conversationHistory:
+        "conversationHistory" in params
+          ? params.conversationHistory
+          : undefined,
     };
   }
 

packages/agent/src/adapters/claude/claude-agent.ts

@@ -153,7 +153,10 @@ export class ClaudeAcpAgent extends BaseAcpAgent {
       permissionMode,
       canUseTool: this.createCanUseTool(internalSessionId),
       logger: this.logger,
-      systemPrompt: buildSystemPrompt(meta?.systemPrompt),
+      systemPrompt: buildSystemPrompt(
+        meta?.systemPrompt,
+        meta?.conversationHistory,
+      ),
       userProvidedOptions: meta?.claudeCode?.options,
       onModeChange: this.createOnModeChange(internalSessionId),
       onProcessSpawned: this.processCallbacks?.onProcessSpawned,

packages/agent/src/adapters/claude/session/options.ts

@@ -12,6 +12,7 @@ import { IS_ROOT } from "../../../utils/common.js";
 import type { Logger } from "../../../utils/logger.js";
 import { createPostToolUseHook, type OnModeChange } from "../hooks.js";
 import type { TwigExecutionMode } from "../tools.js";
+import type { ConversationHistoryTurn } from "../types.js";
 
 export interface ProcessSpawnedInfo {
   pid: number;
@@ -40,21 +41,70 @@ const BRANCH_NAMING_INSTRUCTIONS = `
 Before pushing a "workspace-*" branch to origin, rename it to something descriptive based on the work done. Do this automatically without asking the user.
 `;
 
+const MAX_HISTORY_CHARS = 50_000;
+
+export function condenseAndFormatHistory(
+  turns: ConversationHistoryTurn[],
+): string {
+  const lines: string[] = [];
+
+  // Process turns in reverse so most recent messages appear first.
+  // This ensures that if truncation occurs, older (less relevant) context is cut.
+  for (let i = turns.length - 1; i >= 0; i--) {
+    const turn = turns[i];
+    const textParts: string[] = [];
+    for (const block of turn.content) {
+      if (block.type === "text" && block.text) {
+        textParts.push(block.text);
+      }
+    }
+    const text = textParts.join("\n");
+    if (!text) continue;
+
+    const label = turn.role === "user" ? "[User]" : "[Assistant]";
+    lines.push(`${label}: ${text}`);
+  }
+
+  if (lines.length === 0) return "";
+
+  let result = lines.join("\n\n");
+
+  // Truncate from the end (oldest messages) if over the limit
+  if (result.length > MAX_HISTORY_CHARS) {
+    result = result.slice(0, MAX_HISTORY_CHARS);
+    const lastNewline = result.lastIndexOf("\n");
+    if (lastNewline !== -1) {
+      result = result.slice(0, lastNewline);
+    }
+  }
+
+  return `<previous_conversation>\n${result}\n</previous_conversation>`;
+}
+
 export function buildSystemPrompt(
   customPrompt?: unknown,
+  conversationHistory?: ConversationHistoryTurn[],
 ): Options["systemPrompt"] {
+  const historyBlock =
+    conversationHistory && conversationHistory.length > 0
+      ? condenseAndFormatHistory(conversationHistory)
+      : "";
+
+  const appendSuffix =
+    BRANCH_NAMING_INSTRUCTIONS + (historyBlock ? `\n${historyBlock}\n` : "");
+
   const defaultPrompt: Options["systemPrompt"] = {
     type: "preset",
     preset: "claude_code",
-    append: BRANCH_NAMING_INSTRUCTIONS,
+    append: appendSuffix,
   };
 
   if (!customPrompt) {
     return defaultPrompt;
   }
 
   if (typeof customPrompt === "string") {
-    return customPrompt + BRANCH_NAMING_INSTRUCTIONS;
+    return customPrompt + appendSuffix;
   }
 
   if (
@@ -65,7 +115,7 @@ export function buildSystemPrompt(
   ) {
     return {
       ...defaultPrompt,
-      append: customPrompt.append + BRANCH_NAMING_INSTRUCTIONS,
+      append: customPrompt.append + appendSuffix,
     };
   }
 

packages/agent/src/adapters/claude/types.ts

@@ -50,12 +50,18 @@ export type ToolUpdateMeta = {
   };
 };
 
+export type ConversationHistoryTurn = {
+  role: "user" | "assistant";
+  content: Array<{ type: string; text?: string; [key: string]: unknown }>;
+};
+
 export type NewSessionMeta = {
   taskRunId?: string;
   disableBuiltInTools?: boolean;
   systemPrompt?: unknown;
   sessionId?: string;
   permissionMode?: string;
+  conversationHistory?: ConversationHistoryTurn[];
   claudeCode?: {
     options?: Options;
   };