feat(channels): add systemPrompt support for WhatsApp and Signal

Add per-group and per-DM system prompt configuration for WhatsApp and
Signal channels, mirroring the existing Telegram implementation.

- Add systemPrompt to DmConfig type and schema
- Add systemPrompt to WhatsApp group config (both root and account)
- Add SignalGroupConfig type with systemPrompt and groups config
- Add resolveChannelGroupSystemPrompt() and resolveChannelDmSystemPrompt()
  helpers in group-policy.ts
- Pass GroupSystemPrompt to inbound context in WhatsApp and Signal handlers

src/config/group-policy.ts

@@ -8,6 +8,8 @@ export type GroupPolicyChannel = ChannelId;
 export type ChannelGroupConfig = {
   requireMention?: boolean;
   tools?: GroupToolPolicyConfig;
+  /** Custom system prompt for this group. */
+  systemPrompt?: string;
 };
 
 export type ChannelGroupPolicy = {
@@ -105,3 +107,67 @@ export function resolveChannelGroupToolsPolicy(params: {
   if (defaultConfig?.tools) return defaultConfig.tools;
   return undefined;
 }
+
+/**
+ * Resolve group-specific system prompt from channel config.
+ * Falls back to wildcard (`*`) config if specific group not found.
+ */
+export function resolveChannelGroupSystemPrompt(params: {
+  cfg: ClawdbotConfig;
+  channel: GroupPolicyChannel;
+  groupId?: string | null;
+  accountId?: string | null;
+}): string | undefined {
+  const { groupConfig, defaultConfig } = resolveChannelGroupPolicy(params);
+  if (groupConfig?.systemPrompt?.trim()) return groupConfig.systemPrompt.trim();
+  if (defaultConfig?.systemPrompt?.trim()) return defaultConfig.systemPrompt.trim();
+  return undefined;
+}
+
+type ChannelDmsConfig = Record<
+  string,
+  { historyLimit?: number; systemPrompt?: string } | undefined
+>;
+
+function resolveChannelDms(
+  cfg: ClawdbotConfig,
+  channel: GroupPolicyChannel,
+  accountId?: string | null,
+): ChannelDmsConfig | undefined {
+  const normalizedAccountId = normalizeAccountId(accountId);
+  const channelConfig = cfg.channels?.[channel] as
+    | {
+        accounts?: Record<string, { dms?: ChannelDmsConfig }>;
+        dms?: ChannelDmsConfig;
+      }
+    | undefined;
+  if (!channelConfig) return undefined;
+  const accountDms =
+    channelConfig.accounts?.[normalizedAccountId]?.dms ??
+    channelConfig.accounts?.[
+      Object.keys(channelConfig.accounts ?? {}).find(
+        (key) => key.toLowerCase() === normalizedAccountId.toLowerCase(),
+      ) ?? ""
+    ]?.dms;
+  return accountDms ?? channelConfig.dms;
+}
+
+/**
+ * Resolve DM-specific system prompt from channel config.
+ * Falls back to wildcard (`*`) config if specific DM not found.
+ */
+export function resolveChannelDmSystemPrompt(params: {
+  cfg: ClawdbotConfig;
+  channel: GroupPolicyChannel;
+  dmId?: string | null;
+  accountId?: string | null;
+}): string | undefined {
+  const dms = resolveChannelDms(params.cfg, params.channel, params.accountId);
+  if (!dms) return undefined;
+  const normalizedId = params.dmId?.trim();
+  const dmConfig = normalizedId ? dms[normalizedId] : undefined;
+  const defaultConfig = dms["*"];
+  if (dmConfig?.systemPrompt?.trim()) return dmConfig.systemPrompt.trim();
+  if (defaultConfig?.systemPrompt?.trim()) return defaultConfig.systemPrompt.trim();
+  return undefined;
+}

src/config/types.messages.ts

@@ -8,6 +8,8 @@ export type GroupChatConfig = {
 
 export type DmConfig = {
   historyLimit?: number;
+  /** Custom system prompt for this DM conversation. */
+  systemPrompt?: string;
 };
 
 export type QueueConfig = {

src/config/types.signal.ts

@@ -6,10 +6,20 @@ import type {
 } from "./types.base.js";
 import type { ChannelHeartbeatVisibilityConfig } from "./types.channels.js";
 import type { DmConfig } from "./types.messages.js";
+import type { GroupToolPolicyConfig } from "./types.tools.js";
 
 export type SignalReactionNotificationMode = "off" | "own" | "all" | "allowlist";
 export type SignalReactionLevel = "off" | "ack" | "minimal" | "extensive";
 
+export type SignalGroupConfig = {
+  /** Require explicit bot mention in group messages (default: true). */
+  requireMention?: boolean;
+  /** Tool policy overrides for this group. */
+  tools?: GroupToolPolicyConfig;
+  /** Custom system prompt for this group. */
+  systemPrompt?: string;
+};
+
 export type SignalAccountConfig = {
   /** Optional display name for this account (used in CLI/UI lists). */
   name?: string;
@@ -57,6 +67,8 @@ export type SignalAccountConfig = {
   dmHistoryLimit?: number;
   /** Per-DM config overrides keyed by user ID. */
   dms?: Record<string, DmConfig>;
+  /** Per-group config overrides keyed by group ID. */
+  groups?: Record<string, SignalGroupConfig>;
   /** Outbound text chunk size (chars). Default: 4000. */
   textChunkLimit?: number;
   /** Chunking mode: "length" (default) splits by size; "newline" splits on every newline. */

src/config/types.whatsapp.ts

@@ -70,6 +70,8 @@ export type WhatsAppConfig = {
     {
       requireMention?: boolean;
       tools?: GroupToolPolicyConfig;
+      /** Custom system prompt for this group. */
+      systemPrompt?: string;
     }
   >;
   /** Acknowledgment reaction sent immediately upon message receipt. */
@@ -135,6 +137,8 @@ export type WhatsAppAccountConfig = {
     {
       requireMention?: boolean;
       tools?: GroupToolPolicyConfig;
+      /** Custom system prompt for this group. */
+      systemPrompt?: string;
     }
   >;
   /** Acknowledgment reaction sent immediately upon message receipt. */

src/config/zod-schema.core.ts

@@ -92,6 +92,7 @@ export const GroupChatSchema = z
 export const DmConfigSchema = z
   .object({
     historyLimit: z.number().int().min(0).optional(),
+    systemPrompt: z.string().optional(),
   })
   .strict();
 

src/config/zod-schema.providers-core.ts

@@ -474,6 +474,14 @@ export const SlackConfigSchema = SlackAccountSchema.extend({
   }
 });
 
+export const SignalGroupSchema = z
+  .object({
+    requireMention: z.boolean().optional(),
+    tools: ToolPolicySchema,
+    systemPrompt: z.string().optional(),
+  })
+  .strict();
+
 export const SignalAccountSchemaBase = z
   .object({
     name: z.string().optional(),
@@ -499,6 +507,7 @@ export const SignalAccountSchemaBase = z
     historyLimit: z.number().int().min(0).optional(),
     dmHistoryLimit: z.number().int().min(0).optional(),
     dms: z.record(z.string(), DmConfigSchema.optional()).optional(),
+    groups: z.record(z.string(), SignalGroupSchema.optional()).optional(),
     textChunkLimit: z.number().int().positive().optional(),
     chunkMode: z.enum(["length", "newline"]).optional(),
     blockStreaming: z.boolean().optional(),

src/config/zod-schema.providers-whatsapp.ts

@@ -41,6 +41,7 @@ export const WhatsAppAccountSchema = z
           .object({
             requireMention: z.boolean().optional(),
             tools: ToolPolicySchema,
+            systemPrompt: z.string().optional(),
           })
           .strict()
           .optional(),
@@ -105,6 +106,7 @@ export const WhatsAppConfigSchema = z
           .object({
             requireMention: z.boolean().optional(),
             tools: ToolPolicySchema,
+            systemPrompt: z.string().optional(),
           })
           .strict()
           .optional(),

src/signal/monitor/event-handler.ts

@@ -20,6 +20,10 @@ import { logInboundDrop, logTypingFailure } from "../../channels/logging.js";
 import { createReplyPrefixContext } from "../../channels/reply-prefix.js";
 import { recordInboundSession } from "../../channels/session.js";
 import { createTypingCallbacks } from "../../channels/typing.js";
+import {
+  resolveChannelDmSystemPrompt,
+  resolveChannelGroupSystemPrompt,
+} from "../../config/group-policy.js";
 import { readSessionUpdatedAt, resolveStorePath } from "../../config/sessions.js";
 import { danger, logVerbose, shouldLogVerbose } from "../../globals.js";
 import { enqueueSystemEvent } from "../../infra/system-events.js";
@@ -123,6 +127,22 @@ export function createSignalEventHandler(deps: SignalEventHandlerDeps) {
       });
     }
     const signalTo = entry.isGroup ? `group:${entry.groupId}` : `signal:${entry.senderRecipient}`;
+
+    // Resolve system prompt from group or DM config
+    const groupSystemPrompt = entry.isGroup
+      ? resolveChannelGroupSystemPrompt({
+          cfg: deps.cfg,
+          channel: "signal",
+          groupId: entry.groupId,
+          accountId: deps.accountId,
+        })
+      : resolveChannelDmSystemPrompt({
+          cfg: deps.cfg,
+          channel: "signal",
+          dmId: entry.senderPeerId,
+          accountId: deps.accountId,
+        });
+
     const ctxPayload = finalizeInboundContext({
       Body: combinedBody,
       RawBody: entry.bodyText,
@@ -148,6 +168,7 @@ export function createSignalEventHandler(deps: SignalEventHandlerDeps) {
       CommandAuthorized: entry.commandAuthorized,
       OriginatingChannel: "signal" as const,
       OriginatingTo: signalTo,
+      GroupSystemPrompt: groupSystemPrompt,
     });
 
     await recordInboundSession({

src/web/auto-reply/monitor/process-message.ts

@@ -16,6 +16,10 @@ import { finalizeInboundContext } from "../../../auto-reply/reply/inbound-contex
 import { toLocationContext } from "../../../channels/location.js";
 import { createReplyPrefixContext } from "../../../channels/reply-prefix.js";
 import type { loadConfig } from "../../../config/config.js";
+import {
+  resolveChannelDmSystemPrompt,
+  resolveChannelGroupSystemPrompt,
+} from "../../../config/group-policy.js";
 import {
   readSessionUpdatedAt,
   recordSessionMetaFromInbound,
@@ -255,6 +259,22 @@ export async function processMessage(params: {
       ? (resolveIdentityNamePrefix(params.cfg, params.route.agentId) ?? "[clawdbot]")
       : undefined);
 
+  // Resolve system prompt from group or DM config
+  const groupSystemPrompt =
+    params.msg.chatType === "group"
+      ? resolveChannelGroupSystemPrompt({
+          cfg: params.cfg,
+          channel: "whatsapp",
+          groupId: conversationId,
+          accountId: params.route.accountId,
+        })
+      : resolveChannelDmSystemPrompt({
+          cfg: params.cfg,
+          channel: "whatsapp",
+          dmId: dmRouteTarget,
+          accountId: params.route.accountId,
+        });
+
   const ctxPayload = finalizeInboundContext({
     Body: combinedBody,
     RawBody: params.msg.body,
@@ -288,6 +308,7 @@ export async function processMessage(params: {
     Surface: "whatsapp",
     OriginatingChannel: "whatsapp",
     OriginatingTo: params.msg.from,
+    GroupSystemPrompt: groupSystemPrompt,
   });
 
   if (dmRouteTarget) {