From 36e306f1bc6b307feb83eb92bfcddf6efda80f09 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Thu, 5 Mar 2026 05:04:45 +0000
Subject: [PATCH 01/15] update

---
 examples/src/phonic_realtime_agent.ts         | 15 +++++-
 plugins/phonic/src/realtime/realtime_model.ts | 46 ++++++++++++-------
 2 files changed, 42 insertions(+), 19 deletions(-)

diff --git a/examples/src/phonic_realtime_agent.ts b/examples/src/phonic_realtime_agent.ts
index 2102fab2a..59e92bd10 100644
--- a/examples/src/phonic_realtime_agent.ts
+++ b/examples/src/phonic_realtime_agent.ts
@@ -32,8 +32,9 @@ export default defineAgent({
       // Uses PHONIC_API_KEY environment variable when apiKey is not provided
       llm: new phonic.realtime.RealtimeModel({
         voice: 'sabrina',
-        welcomeMessage: 'Hey there, how can I help you today?',
+        // welcomeMessage: 'Hey there, how can I help you today?',
         audioSpeed: 1.2,
+        baseUrl: 'http://localhost:3520',
       }),
     });
 
@@ -43,7 +44,17 @@ export default defineAgent({
     });
 
     await ctx.connect();
+
+    // await session.generateReply({
+    //   instructions: 'greet the user and ask about their day',
+    // });
+
+    // setInterval(async () => {
+    //   await session.generateReply({
+    //     instructions: 'tell the user that you like Port of Parity Parity, which is a restaurant in san francisco',
+    //   });
+    // }, 15 * 1000);
   },
 });
 
-cli.runApp(new ServerOptions({ agent: fileURLToPath(import.meta.url) }));
+cli.runApp(new ServerOptions({ agent: fileURLToPath(import.meta.url), agentName: "qiong-generate-1" }));
diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index 6baf75499..cf22744fe 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -261,7 +261,7 @@ export class RealtimeSession extends llm.RealtimeSession {
         'updateChatCtx called but no new tool call outputs to send. Phonic does not support general chat context updates.',
       );
     } else {
-      this.startNewAssistantTurn();
+      this.startNewAssistantTurn({ userInitiated: false });
     }
   }
 
@@ -322,11 +322,20 @@ export class RealtimeSession extends llm.RealtimeSession {
     }
   }
 
-  // TODO @Phonic-Co: Implement generateReply
-  async generateReply(_instructions?: string): Promise<llm.GenerationCreatedEvent> {
-    throw new Error(
-      'generateReply is not yet supported by the Phonic realtime model. Consider using `welcomeMessage` instead.',
-    );
+  async generateReply(instructions?: string): Promise<llm.GenerationCreatedEvent> {
+    const systemMessage = instructions ?? 'Please say something.'
+    const payload = { type: 'generate_reply' as const, system_message: systemMessage };
+
+    // temp
+    if (this.socket) {
+      const ws = this.socket.socket;
+      ws?.send(JSON.stringify(payload));
+    } else {
+      this.logger.warn('Cannot send generate_reply: WebSocket not available');
+    }
+
+    this.closeCurrentGeneration({ interrupted: false });
+    return this.startNewAssistantTurn({ userInitiated: true });
   }
 
   async commitAudio(): Promise<void> {
@@ -412,7 +421,9 @@ export class RealtimeSession extends llm.RealtimeSession {
 
     switch (message.type) {
       case 'assistant_started_speaking':
-        this.startNewAssistantTurn();
+        if (this.currentGeneration === undefined) {
+          this.startNewAssistantTurn({ userInitiated: false });
+        }
         break;
       case 'assistant_finished_speaking':
         this.finishAssistantTurn();
@@ -469,7 +480,7 @@ export class RealtimeSession extends llm.RealtimeSession {
      */
     if (this.currentGeneration === undefined && message.text) {
       this.logger.debug('Starting new generation due to text in audio chunk');
-      this.startNewAssistantTurn();
+      this.startNewAssistantTurn({ userInitiated: false });
     }
 
     const gen = this.currentGeneration;
@@ -521,7 +532,7 @@ export class RealtimeSession extends llm.RealtimeSession {
 
     if (this.currentGeneration === undefined) {
       this.logger.warn('Encountered tool call but no active generation. Starting new turn.');
-      this.startNewAssistantTurn();
+      this.startNewAssistantTurn({ userInitiated: false });
     }
 
     this.currentGeneration!.functionChannel.write(
@@ -553,11 +564,9 @@ export class RealtimeSession extends llm.RealtimeSession {
     });
   }
 
-  private startNewAssistantTurn(): void {
-    if (this.currentGeneration) {
-      this.closeCurrentGeneration({ interrupted: true });
-    }
-
+  private startNewAssistantTurn(options: {
+    userInitiated: boolean;
+  }): llm.GenerationCreatedEvent {
     const responseId = shortuuid('PS_');
 
     const textChannel = stream.createStreamChannel<string>();
@@ -581,12 +590,15 @@ export class RealtimeSession extends llm.RealtimeSession {
       outputText: '',
     };
 
-    this.emit('generation_created', {
+    const generationEvent: llm.GenerationCreatedEvent = {
       messageStream: messageChannel.stream(),
       functionStream: functionChannel.stream(),
-      userInitiated: false,
+      userInitiated: options.userInitiated,
       responseId,
-    });
+    };
+
+    this.emit('generation_created', generationEvent);
+    return generationEvent;
   }
 
   private finishAssistantTurn(): void {

From b45bee7915be6f8bdf78793e7658fffdceb0d7a8 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 01:46:11 +0000
Subject: [PATCH 02/15] Update sdk

---
 examples/src/phonic_realtime_agent.ts         | 12 +++---------
 plugins/phonic/package.json                   |  2 +-
 plugins/phonic/src/realtime/realtime_model.ts |  7 +------
 pnpm-lock.yaml                                | 10 +++++-----
 4 files changed, 10 insertions(+), 21 deletions(-)

diff --git a/examples/src/phonic_realtime_agent.ts b/examples/src/phonic_realtime_agent.ts
index 59e92bd10..b3a3b46cf 100644
--- a/examples/src/phonic_realtime_agent.ts
+++ b/examples/src/phonic_realtime_agent.ts
@@ -45,15 +45,9 @@ export default defineAgent({
 
     await ctx.connect();
 
-    // await session.generateReply({
-    //   instructions: 'greet the user and ask about their day',
-    // });
-
-    // setInterval(async () => {
-    //   await session.generateReply({
-    //     instructions: 'tell the user that you like Port of Parity Parity, which is a restaurant in san francisco',
-    //   });
-    // }, 15 * 1000);
+    await session.generateReply({
+      instructions: 'Greet the user, asking about their day.',
+    });
   },
 });
 
diff --git a/plugins/phonic/package.json b/plugins/phonic/package.json
index 219af9fae..6e06b2412 100644
--- a/plugins/phonic/package.json
+++ b/plugins/phonic/package.json
@@ -41,7 +41,7 @@
     "typescript": "^5.0.0"
   },
   "dependencies": {
-    "phonic": "^0.30.39"
+    "phonic": "^0.31.2"
   },
   "peerDependencies": {
     "@livekit/agents": "workspace:*",
diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index cf22744fe..245f18165 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -323,13 +323,8 @@ export class RealtimeSession extends llm.RealtimeSession {
   }
 
   async generateReply(instructions?: string): Promise<llm.GenerationCreatedEvent> {
-    const systemMessage = instructions ?? 'Please say something.'
-    const payload = { type: 'generate_reply' as const, system_message: systemMessage };
-
-    // temp
     if (this.socket) {
-      const ws = this.socket.socket;
-      ws?.send(JSON.stringify(payload));
+      this.socket.sendGenerateReply({ type: 'generate_reply', system_message: instructions });
     } else {
       this.logger.warn('Cannot send generate_reply: WebSocket not available');
     }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 94cda9f29..c8a126114 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -752,8 +752,8 @@ importers:
   plugins/phonic:
     dependencies:
       phonic:
-        specifier: ^0.30.39
-        version: 0.30.39
+        specifier: ^0.31.2
+        version: 0.31.2
     devDependencies:
       '@livekit/agents':
         specifier: workspace:*
@@ -4393,8 +4393,8 @@ packages:
     resolution: {integrity: sha512-vE7JKRyES09KiunauX7nd2Q9/L7lhok4smP9RZTDeD4MVs72Dp2qNFVz39Nz5a0FVEW0BJR6C0DYrq6unoziZA==}
     engines: {node: '>= 14.16'}
 
-  phonic@0.30.39:
-    resolution: {integrity: sha512-4XcTtzt9Q32GkufSilpPl+6qyTpgJasjUKz4tMfuQ65VHglOygDcMISbmDwKuFJSJUURb1l8T0Kw5GnEXSHCFA==}
+  phonic@0.31.2:
+    resolution: {integrity: sha512-vpFBFpJYCjgqG2RPe+z3EmwLu/HN8CX1A9kEvNestpm/PWhaGLcEL3ySZmm+AOCaDeRykdhdJ5smEFKj20gd4Q==}
     engines: {node: '>=18.0.0'}
 
   picocolors@1.0.1:
@@ -8958,7 +8958,7 @@ snapshots:
 
   pathval@2.0.0: {}
 
-  phonic@0.30.39:
+  phonic@0.31.2:
     dependencies:
       ws: 8.18.3
     transitivePeerDependencies:

From 9b21cb0bb16256254e7c9cf5a2130e5cc5aa6d97 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 02:13:56 +0000
Subject: [PATCH 03/15] cleanup

---
 examples/src/phonic_realtime_agent.ts         |  4 +---
 plugins/phonic/README.md                      | 10 +++++++++-
 plugins/phonic/src/realtime/realtime_model.ts |  6 ++++--
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/examples/src/phonic_realtime_agent.ts b/examples/src/phonic_realtime_agent.ts
index b3a3b46cf..660ad9277 100644
--- a/examples/src/phonic_realtime_agent.ts
+++ b/examples/src/phonic_realtime_agent.ts
@@ -32,9 +32,7 @@ export default defineAgent({
       // Uses PHONIC_API_KEY environment variable when apiKey is not provided
       llm: new phonic.realtime.RealtimeModel({
         voice: 'sabrina',
-        // welcomeMessage: 'Hey there, how can I help you today?',
         audioSpeed: 1.2,
-        baseUrl: 'http://localhost:3520',
       }),
     });
 
@@ -51,4 +49,4 @@ export default defineAgent({
   },
 });
 
-cli.runApp(new ServerOptions({ agent: fileURLToPath(import.meta.url), agentName: "qiong-generate-1" }));
+cli.runApp(new ServerOptions({ agent: fileURLToPath(import.meta.url) }));
diff --git a/plugins/phonic/README.md b/plugins/phonic/README.md
index 4b7bec8a4..f58c25b09 100644
--- a/plugins/phonic/README.md
+++ b/plugins/phonic/README.md
@@ -5,6 +5,9 @@ Realtime voice AI integration for [Phonic](https://phonic.co/) with LiveKit Agen
 ## Usage
 
 ```typescript
+// SPDX-FileCopyrightText: 2026 LiveKit, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
 import { type JobContext, ServerOptions, cli, defineAgent, llm, voice } from '@livekit/agents';
 import * as phonic from '@livekit/agents-plugin-phonic';
 import { fileURLToPath } from 'node:url';
@@ -18,6 +21,7 @@ const toggleLight = llm.tool({
   }),
   execute: async ({ light_id, state }) => {
     console.log(`Turning ${state} light ${light_id}`);
+    await new Promise((resolve) => setTimeout(resolve, 1_000));
     return `Light ${light_id} turned ${state}`;
   },
 });
@@ -35,7 +39,6 @@ export default defineAgent({
       // Uses PHONIC_API_KEY environment variable when apiKey is not provided
       llm: new phonic.realtime.RealtimeModel({
         voice: 'sabrina',
-        welcomeMessage: 'Hey there, how can I help you today?',
         audioSpeed: 1.2,
       }),
     });
@@ -46,10 +49,15 @@ export default defineAgent({
     });
 
     await ctx.connect();
+
+    await session.generateReply({
+      instructions: 'Greet the user, asking about their day.',
+    });
   },
 });
 
 cli.runApp(new ServerOptions({ agent: fileURLToPath(import.meta.url) }));
+
 ```
 
 ## Configuration
diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index 245f18165..d10ca1478 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -559,7 +559,9 @@ export class RealtimeSession extends llm.RealtimeSession {
     });
   }
 
-  private startNewAssistantTurn(options: {
+  private startNewAssistantTurn({
+    userInitiated,
+  }: {
     userInitiated: boolean;
   }): llm.GenerationCreatedEvent {
     const responseId = shortuuid('PS_');
@@ -588,7 +590,7 @@ export class RealtimeSession extends llm.RealtimeSession {
     const generationEvent: llm.GenerationCreatedEvent = {
       messageStream: messageChannel.stream(),
       functionStream: functionChannel.stream(),
-      userInitiated: options.userInitiated,
+      userInitiated,
       responseId,
     };
 

From da0631c2e29ced8846e4f97c4f29d7e0333f2220 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 03:30:14 +0000
Subject: [PATCH 04/15] Add changeset

---
 .changeset/curvy-rooms-agree.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/curvy-rooms-agree.md

diff --git a/.changeset/curvy-rooms-agree.md b/.changeset/curvy-rooms-agree.md
new file mode 100644
index 000000000..16464796d
--- /dev/null
+++ b/.changeset/curvy-rooms-agree.md
@@ -0,0 +1,5 @@
+---
+'@livekit/agents-plugin-phonic': patch
+---
+
+Add generateReply support to Phonic plugin

From 7539f78c3b70ecf371b304cc558098e481277cc4 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 04:11:11 +0000
Subject: [PATCH 05/15] Add back safety check

---
 plugins/phonic/src/realtime/realtime_model.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index d10ca1478..9c5894a5e 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -564,6 +564,10 @@ export class RealtimeSession extends llm.RealtimeSession {
   }: {
     userInitiated: boolean;
   }): llm.GenerationCreatedEvent {
+    if (this.currentGeneration) {
+      this.closeCurrentGeneration({ interrupted: true });
+    }
+
     const responseId = shortuuid('PS_');
 
     const textChannel = stream.createStreamChannel<string>();

From 9a2a6ea6650ebf5d143649549da09b53bd50de8e Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 18:18:03 +0000
Subject: [PATCH 06/15] Allow updating chat context prior to config senting and
 to add system messages

---
 plugins/phonic/src/realtime/realtime_model.ts | 39 +++++++++++++++----
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index 9c5894a5e..2428468f6 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -202,7 +202,9 @@ export class RealtimeSession extends llm.RealtimeSession {
   private connectTask: Promise<void>;
   private toolDefinitions: Record<string, unknown>[] = [];
   private pendingToolCallIds = new Set<string>();
+  private lastAgentChatCtx = llm.ChatContext.empty();
   private readyToStart = false;
+  private systemPromptPostfix = '';
 
   constructor(realtimeModel: RealtimeModel) {
     super(realtimeModel);
@@ -243,9 +245,21 @@ export class RealtimeSession extends llm.RealtimeSession {
   }
 
   async updateChatCtx(chatCtx: llm.ChatContext): Promise<void> {
-    let sent = false;
-    for (const item of chatCtx.items) {
-      if (item.type === 'function_call_output' && this.pendingToolCallIds.has(item.callId)) {
+    if (!this.configSent) {
+      if (chatCtx.items.length > 0) {
+        this.logger.debug("updateChatCtx called prior to config being sent to Phonic. Including conversation state in system instructions.")
+        const turnHistory = chatCtx.items.filter((item) => item.type === 'message').map((item) => `${item.role}: ${item.content.join('\n')}`).join('\n');
+        this.systemPromptPostfix = "This conversation is being continued from an existing conversation. The following is the conversation history. You are the assistant speaking to the user." + turnHistory
+      }
+    }
+
+    const diffOps = llm.computeChatCtxDiff(this._chatCtx, chatCtx);
+    let sentToolCallOutput = false;
+    let sentAddSystemMessage = false;
+  
+    for (const [, itemId] of diffOps.toCreate) {
+      const item = chatCtx.getById(itemId);
+      if (item?.type === 'function_call_output' && this.pendingToolCallIds.has(item.callId)) {
         this.pendingToolCallIds.delete(item.callId);
         this.logger.info(`Sending tool call output for ${item.name} (call_id: ${item.callId})`);
         this.socket?.sendToolCallOutput({
@@ -253,14 +267,25 @@ export class RealtimeSession extends llm.RealtimeSession {
           tool_call_id: item.callId,
           output: item.output,
         });
-        sent = true;
+        sentToolCallOutput = true;
+      }
+      if (item?.type === 'message' && item.role === 'system' && typeof item.content === 'string') {
+        this.socket?.sendAddSystemMessage({
+          type: 'add_system_message',
+          system_message: item.content,
+        });
+        sentAddSystemMessage = true;
       }
     }
-    if (!sent) {
+
+    this._chatCtx = chatCtx.copy()
+
+    if (!sentToolCallOutput && !sentAddSystemMessage) {
       this.logger.warn(
         'updateChatCtx called but no new tool call outputs to send. Phonic does not support general chat context updates.',
       );
-    } else {
+    }
+    if (sentToolCallOutput) {
       this.startNewAssistantTurn({ userInitiated: false });
     }
   }
@@ -394,7 +419,7 @@ export class RealtimeSession extends llm.RealtimeSession {
       project: this.options.project,
       welcome_message: this.options.welcomeMessage,
       generate_welcome_message: this.options.generateWelcomeMessage,
-      system_prompt: this.options.instructions,
+      system_prompt: this.options.instructions + this.systemPromptPostfix,
       voice_id: this.options.voice,
       input_format: 'pcm_44100',
       output_format: 'pcm_44100',

From 17fe458caf21fb8aef5cf311829b176d861b2900 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 18:18:47 +0000
Subject: [PATCH 07/15] Allow developer

---
 plugins/phonic/src/realtime/realtime_model.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index 2428468f6..9a1bffd93 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -269,7 +269,7 @@ export class RealtimeSession extends llm.RealtimeSession {
         });
         sentToolCallOutput = true;
       }
-      if (item?.type === 'message' && item.role === 'system' && typeof item.content === 'string') {
+      if (item?.type === 'message' && (item.role === 'system' || item.role === 'developer') && typeof item.content === 'string') {
         this.socket?.sendAddSystemMessage({
           type: 'add_system_message',
           system_message: item.content,

From 75dda35decdafba0bd6edfceb919c4a51d541df1 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 19:11:00 +0000
Subject: [PATCH 08/15] fixes

---
 examples/src/phonic_realtime_agent.ts         | 14 +++++++++++++
 plugins/phonic/src/realtime/realtime_model.ts | 20 +++++++++++--------
 2 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/examples/src/phonic_realtime_agent.ts b/examples/src/phonic_realtime_agent.ts
index 660ad9277..fac2fea61 100644
--- a/examples/src/phonic_realtime_agent.ts
+++ b/examples/src/phonic_realtime_agent.ts
@@ -46,6 +46,20 @@ export default defineAgent({
     await session.generateReply({
       instructions: 'Greet the user, asking about their day.',
     });
+
+    setTimeout(async () => {
+      const agent = session.currentAgent;
+      const chatCtx = agent.chatCtx.copy();
+      chatCtx.addMessage({
+        role: 'system',
+        content:
+          'You really like the Port of Peri Peri (restaurant in San Francisco). Let the user know that.',
+      });
+      await agent.updateChatCtx(chatCtx);
+      // session.generateReply({
+      //   instructions: 'Mention to the user that you really like the Port of Peri Peri restaurant.',
+      // });
+    }, 10000);
   },
 });
 
diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index 9a1bffd93..1d75bf3b5 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -248,9 +248,10 @@ export class RealtimeSession extends llm.RealtimeSession {
     if (!this.configSent) {
       if (chatCtx.items.length > 0) {
         this.logger.debug("updateChatCtx called prior to config being sent to Phonic. Including conversation state in system instructions.")
-        const turnHistory = chatCtx.items.filter((item) => item.type === 'message').map((item) => `${item.role}: ${item.content.join('\n')}`).join('\n');
-        this.systemPromptPostfix = "This conversation is being continued from an existing conversation. The following is the conversation history. You are the assistant speaking to the user." + turnHistory
+        const turnHistory = chatCtx.items.filter((item) => item.type === 'message' && 'textContent' in item).map((item) => `${item.role}: ${item.textContent}`).join('\n');
+        this.systemPromptPostfix = "\n\nThis conversation is being continued from an existing conversation. You are the assistant speaking to the user. The following is the conversation history:\n" + turnHistory
       }
+      return;
     }
 
     const diffOps = llm.computeChatCtxDiff(this._chatCtx, chatCtx);
@@ -269,12 +270,15 @@ export class RealtimeSession extends llm.RealtimeSession {
         });
         sentToolCallOutput = true;
       }
-      if (item?.type === 'message' && (item.role === 'system' || item.role === 'developer') && typeof item.content === 'string') {
-        this.socket?.sendAddSystemMessage({
-          type: 'add_system_message',
-          system_message: item.content,
-        });
-        sentAddSystemMessage = true;
+      if (item?.type === 'message') {
+        if ((item.role === 'system' || item.role === 'developer') && item.textContent) {
+          this.logger.debug(`Sending add system message: ${item.textContent}`);
+          this.socket?.sendAddSystemMessage({
+            type: 'add_system_message',
+            system_message: item.textContent,
+          });
+          sentAddSystemMessage = true;
+        }
       }
     }
 

From c1bf6ba8651772ff195292a32170c09c1c4ef1b2 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 19:12:36 +0000
Subject: [PATCH 09/15] remove

---
 examples/src/phonic_realtime_agent.ts | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/examples/src/phonic_realtime_agent.ts b/examples/src/phonic_realtime_agent.ts
index fac2fea61..c80fca4a4 100644
--- a/examples/src/phonic_realtime_agent.ts
+++ b/examples/src/phonic_realtime_agent.ts
@@ -56,9 +56,6 @@ export default defineAgent({
           'You really like the Port of Peri Peri (restaurant in San Francisco). Let the user know that.',
       });
       await agent.updateChatCtx(chatCtx);
-      // session.generateReply({
-      //   instructions: 'Mention to the user that you really like the Port of Peri Peri restaurant.',
-      // });
     }, 10000);
   },
 });

From 915142228c9a59c6bcbcdd89653ef7d36e2a3ab7 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Fri, 6 Mar 2026 19:32:37 +0000
Subject: [PATCH 10/15] format

---
 plugins/phonic/src/realtime/realtime_model.ts | 23 +++++++++++++++----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index 1d75bf3b5..ddff52ee7 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -247,9 +247,22 @@ export class RealtimeSession extends llm.RealtimeSession {
   async updateChatCtx(chatCtx: llm.ChatContext): Promise<void> {
     if (!this.configSent) {
       if (chatCtx.items.length > 0) {
-        this.logger.debug("updateChatCtx called prior to config being sent to Phonic. Including conversation state in system instructions.")
-        const turnHistory = chatCtx.items.filter((item) => item.type === 'message' && 'textContent' in item).map((item) => `${item.role}: ${item.textContent}`).join('\n');
-        this.systemPromptPostfix = "\n\nThis conversation is being continued from an existing conversation. You are the assistant speaking to the user. The following is the conversation history:\n" + turnHistory
+        this.logger.debug(
+          'updateChatCtx called prior to config being sent to Phonic. Including conversation state in system instructions.',
+        );
+        const turnHistory = chatCtx.items
+          .filter(
+            (item): item is llm.ChatMessage =>
+              item.type === 'message' &&
+              'textContent' in item &&
+              item.textContent !== undefined &&
+              item.textContent.trim() !== '',
+          )
+          .map((item) => `${item.role}: ${item.textContent}`)
+          .join('\n');
+        this.systemPromptPostfix =
+          '\n\nThis conversation is being continued from an existing conversation. You are the assistant speaking to the user. The following is the conversation history:\n' +
+          turnHistory;
       }
       return;
     }
@@ -257,7 +270,7 @@ export class RealtimeSession extends llm.RealtimeSession {
     const diffOps = llm.computeChatCtxDiff(this._chatCtx, chatCtx);
     let sentToolCallOutput = false;
     let sentAddSystemMessage = false;
-  
+
     for (const [, itemId] of diffOps.toCreate) {
       const item = chatCtx.getById(itemId);
       if (item?.type === 'function_call_output' && this.pendingToolCallIds.has(item.callId)) {
@@ -282,7 +295,7 @@ export class RealtimeSession extends llm.RealtimeSession {
       }
     }
 
-    this._chatCtx = chatCtx.copy()
+    this._chatCtx = chatCtx.copy();
 
     if (!sentToolCallOutput && !sentAddSystemMessage) {
       this.logger.warn(

From 1904d8e9bf839b514c52f41712ca4229b4c6616d Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Mon, 9 Mar 2026 18:37:19 +0000
Subject: [PATCH 11/15] Fixes

---
 plugins/phonic/src/realtime/realtime_model.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index ddff52ee7..db42a523d 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -202,7 +202,6 @@ export class RealtimeSession extends llm.RealtimeSession {
   private connectTask: Promise<void>;
   private toolDefinitions: Record<string, unknown>[] = [];
   private pendingToolCallIds = new Set<string>();
-  private lastAgentChatCtx = llm.ChatContext.empty();
   private readyToStart = false;
   private systemPromptPostfix = '';
 
@@ -263,6 +262,7 @@ export class RealtimeSession extends llm.RealtimeSession {
         this.systemPromptPostfix =
           '\n\nThis conversation is being continued from an existing conversation. You are the assistant speaking to the user. The following is the conversation history:\n' +
           turnHistory;
+        this._chatCtx = chatCtx.copy();
       }
       return;
     }

From 0ffb85ba68d7d0545fecf22df940611cdac5b909 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Mon, 9 Mar 2026 20:23:42 +0000
Subject: [PATCH 12/15] update example

---
 examples/src/phonic_realtime_agent.ts | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/examples/src/phonic_realtime_agent.ts b/examples/src/phonic_realtime_agent.ts
index c80fca4a4..e873166d4 100644
--- a/examples/src/phonic_realtime_agent.ts
+++ b/examples/src/phonic_realtime_agent.ts
@@ -48,12 +48,13 @@ export default defineAgent({
     });
 
     setTimeout(async () => {
+      if (session.agentState === 'initializing') return;
       const agent = session.currentAgent;
       const chatCtx = agent.chatCtx.copy();
       chatCtx.addMessage({
         role: 'system',
         content:
-          'You really like the Port of Peri Peri (restaurant in San Francisco). Let the user know that.',
+          "The user's name is Alex. He is from San Francisco and likes hiking. Use this information in your conversation.",
       });
       await agent.updateChatCtx(chatCtx);
     }, 10000);

From 95f91410ca0c38a9fa51a0021bddefb466a84864 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Mon, 9 Mar 2026 21:19:27 +0000
Subject: [PATCH 13/15] Add changeset

---
 .changeset/silly-rats-walk.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/silly-rats-walk.md

diff --git a/.changeset/silly-rats-walk.md b/.changeset/silly-rats-walk.md
new file mode 100644
index 000000000..af530f812
--- /dev/null
+++ b/.changeset/silly-rats-walk.md
@@ -0,0 +1,5 @@
+---
+'@livekit/agents-plugin-phonic': patch
+---
+
+Add support for updateChatCtx to rehydrate conversations prior to conversation start to add system messages during an ongoing conversation

From 9259fde46b60988b90269f0705b55237080c86d0 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Mon, 9 Mar 2026 21:28:20 +0000
Subject: [PATCH 14/15] require defined instructions

---
 plugins/phonic/src/realtime/realtime_model.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index db42a523d..d699e3f6c 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -428,6 +428,14 @@ export class RealtimeSession extends llm.RealtimeSession {
     await this.toolsReady.await;
     if (this.closed) return;
 
+    if (this.options.instructions === undefined) {
+      this.emitError(
+        new Error('Instructions are required to start a conversation with Phonic.'),
+        false,
+      );
+      return;
+    }
+
     this.configSent = true;
     this.socket.sendConfig({
       type: 'config',

From c8efe5cb6581161731cf413bdfd2d1ed36378372 Mon Sep 17 00:00:00 2001
From: Qiong Zhou Huang <qiong@phonic.co>
Date: Mon, 9 Mar 2026 21:42:23 +0000
Subject: [PATCH 15/15] guard against empty turns

---
 plugins/phonic/src/realtime/realtime_model.ts | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/plugins/phonic/src/realtime/realtime_model.ts b/plugins/phonic/src/realtime/realtime_model.ts
index d699e3f6c..47d712b6f 100644
--- a/plugins/phonic/src/realtime/realtime_model.ts
+++ b/plugins/phonic/src/realtime/realtime_model.ts
@@ -246,9 +246,6 @@ export class RealtimeSession extends llm.RealtimeSession {
   async updateChatCtx(chatCtx: llm.ChatContext): Promise<void> {
     if (!this.configSent) {
       if (chatCtx.items.length > 0) {
-        this.logger.debug(
-          'updateChatCtx called prior to config being sent to Phonic. Including conversation state in system instructions.',
-        );
         const turnHistory = chatCtx.items
           .filter(
             (item): item is llm.ChatMessage =>
@@ -259,9 +256,14 @@ export class RealtimeSession extends llm.RealtimeSession {
           )
           .map((item) => `${item.role}: ${item.textContent}`)
           .join('\n');
-        this.systemPromptPostfix =
-          '\n\nThis conversation is being continued from an existing conversation. You are the assistant speaking to the user. The following is the conversation history:\n' +
-          turnHistory;
+        if (turnHistory.trim() !== '') {
+          this.logger.debug(
+            'updateChatCtx called with messages prior to config being sent to Phonic. Including conversation state in system instructions.',
+          );
+          this.systemPromptPostfix =
+            '\n\nThis conversation is being continued from an existing conversation. You are the assistant speaking to the user. The following is the conversation history:\n' +
+            turnHistory;
+        }
         this._chatCtx = chatCtx.copy();
       }
       return;