Srihari Sriraman shared in

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Fixed coding agent session sync issuePublic

Agent

Model

Claude Opus 4.5 (latest)

Started

Jan 26, 8:59 PM

Messages127

Downloads0

Summary

Closed, Completed

Understand
Reviewed GitHub issue and related code.
Understand
Build
Created minimal test extension.
Build
Verify
Tested extension and confirmed fix.
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Edit
Added changelog entry, committed, and pushed.
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Analyze GitHub issue(s): https://github.com/badlogic/pi-mono/issues/968

For each issue:

Read the issue in full, including all comments and linked issues/PRs.
For bugs:
- Ignore any root cause analysis in the issue (likely wrong)
- Read all related code files in full (no truncation)
- Trace the code path and identify the actual root cause
- Propose a fix
For feature requests:
- Read all related code files in full (no truncation)
- Propose the most concise implementation approach
- List affected files and changes needed

Do NOT implement unless explicitly asked. Analyze and propose only.

Let me download and examine the attached extension file:

Now let me examine the relevant code. I'll look at how newSession and navigateTree work:

Let me continue reading the file and also look at the agent-session.ts file:

Now I have a complete picture of the issue. Let me summarize my analysis:

Issue Analysis: #968 - Creating new sessions with appended messages is broken

Problem Summary

When an extension creates a new session using ctx.newSession() with a setup callback that appends messages, the UI and LLM context don't properly reflect those messages. The user has to call navigateTree twice as a workaround.

Root Cause

In packages/coding-agent/src/modes/interactive/interactive-mode.ts, the newSession handler has a fundamental flaw:

typescript

// lines ~875-905newSession: async (options) => {    // ...    const success = await this.session.newSession({ parentSession: options?.parentSession });        if (options?.setup) {        await options.setup(this.sessionManager);  // Messages are appended to SessionManager    }
    // BUT: Agent state is NOT synced after setup()    // The agent was reset in session.newSession(), and messages added via setup()    // are only in the SessionManager, not in the Agent's state.
    this.chatContainer.clear();    // ...renders "✓ New session started" instead of the actual messages    this.chatContainer.addChild(new Text(`${theme.fg("accent", "✓ New session started")}`, 1, 1));        return { cancelled: false };};

The issue is that:

Agent state not synced: this.session.agent.replaceMessages() is never called after setup() runs, so the Agent has no knowledge of the appended messages
UI not rendered: renderInitialMessages() is never called, so the chat container just shows "New session started" instead of the actual messages
Leaf position: The session manager's leaf pointer may not be at the correct position after messages are appended

The navigateTree workaround works because it:

Calls sessionManager.buildSessionContext() to get messages
Calls agent.replaceMessages(sessionContext.messages) to sync the agent
Calls renderInitialMessages() to render the UI

Proposed Fix

In packages/coding-agent/src/modes/interactive/interactive-mode.ts, modify the newSession handler:

Before:

typescript

if (options?.setup) {    await options.setup(this.sessionManager);}
this.chatContainer.clear();// ...this.chatContainer.addChild(new Text(`${theme.fg("accent", "✓ New session started")}`, 1, 1));

After:

typescript

if (options?.setup) {    await options.setup(this.sessionManager);        // Sync agent state with session manager after setup    const sessionContext = this.sessionManager.buildSessionContext();    this.session.agent.replaceMessages(sessionContext.messages);}
this.chatContainer.clear();this.pendingMessagesContainer.clear();this.compactionQueuedMessages = [];this.streamingComponent = undefined;this.streamingMessage = undefined;this.pendingTools.clear();
// Render messages if any were added via setup, otherwise show simple confirmationconst hasMessages = this.sessionManager.getBranch().some(e => e.type === 'message');if (hasMessages) {    this.renderInitialMessages();} else {    this.chatContainer.addChild(new Spacer(1));    this.chatContainer.addChild(new Text(`${theme.fg("accent", "✓ New session started")}`, 1, 1));}
this.ui.requestRender();

Affected Files

packages/coding-agent/src/modes/interactive/interactive-mode.ts (lines ~875-910)

Additional Considerations

The sessionManager.appendMessage() returns an entry ID, but doesn't update the leaf pointer. After appending multiple messages, the session tree structure may need the leaf to be set to the last entry. This might require also calling sessionManager.branch(lastEntryId) or similar.
The RPC mode (packages/coding-agent/src/modes/rpc/rpc-mode.ts) may have a similar issue if it exposes newSession with setup callbacks.

what. why doesn't this go through agent-session.ts which should handle all this crap, and interactive-mode and rpc mode just do the UI/RPC parts? also, why would appendMessage on session manager not push the leaf??

You're absolutely right. Let me check the actual architecture:

You're completely right. Let me trace the architecture issue:

So the issue is clear:

appendMessage DOES update the leaf - that's fine:

typescript

private _appendEntry(entry: SessionEntry): void {    this.fileEntries.push(entry);    this.byId.set(entry.id, entry);    this.leafId = entry.id;  // ✓ Leaf is updated    this._persist(entry);}

The setup callback is defined in extension types but handled in interactive-mode, not agent-session:
- ExtensionCommandContext.newSession({ setup }) is what extensions call
- But AgentSession.newSession() has NO setup parameter
- Interactive-mode handles setup locally and never syncs agent state

Proposed Fix

Move setup handling to AgentSession.newSession():

File: packages/coding-agent/src/core/agent-session.ts

typescript

// Change NewSessionOptions or add setup parameterasync newSession(options?: {    parentSession?: string;    setup?: (sessionManager: SessionManager) => Promise<void>;}): Promise<boolean> {    // ... existing event emission and abort logic ...        this._disconnectFromAgent();    await this.abort();    this.agent.reset();    this.sessionManager.newSession({ parentSession: options?.parentSession });    this.agent.sessionId = this.sessionManager.getSessionId();    this._steeringMessages = [];    this._followUpMessages = [];    this._pendingNextTurnMessages = [];        // NEW: Run setup if provided    if (options?.setup) {        await options.setup(this.sessionManager);        // Sync agent state with session manager        const sessionContext = this.sessionManager.buildSessionContext();        this.agent.replaceMessages(sessionContext.messages);    }        this._reconnectToAgent();    // ... rest of method ...}

File: packages/coding-agent/src/modes/interactive/interactive-mode.ts

Simplify the handler to just do UI:

typescript

newSession: async (options) => {    // Clear UI loading state    if (this.loadingAnimation) {        this.loadingAnimation.stop();        this.loadingAnimation = undefined;    }    this.statusContainer.clear();
    // Delegate to AgentSession (handles setup + agent sync)    const success = await this.session.newSession(options);    if (!success) {        return { cancelled: true };    }
    // UI cleanup    this.chatContainer.clear();    this.pendingMessagesContainer.clear();    this.compactionQueuedMessages = [];    this.streamingComponent = undefined;    this.streamingMessage = undefined;    this.pendingTools.clear();
    // Render messages (works whether setup added messages or not)    this.renderInitialMessages();    this.ui.requestRender();
    return { cancelled: false };},

Affected Files:

packages/coding-agent/src/core/agent-session.ts - Add setup parameter, sync agent after setup
packages/coding-agent/src/core/session-manager.ts - No changes needed (already exports NewSessionOptions, may need to extend it or keep separate)
packages/coding-agent/src/modes/interactive/interactive-mode.ts - Remove local setup handling, just call renderInitialMessages()
packages/coding-agent/src/modes/rpc/rpc-mode.ts - Check if it has similar issues

implemnent

Now let me implement the fix:

Now let me check RPC mode for similar issues:

RPC mode has the same issue. Let me fix it:

Now let's run the check:

Let me clean up the unused import:

Now let me update the changelog:

Done. Here's the summary:

Changes Made

packages/coding-agent/src/core/agent-session.ts

Extended newSession() to accept a setup callback parameter
After setup() runs, syncs agent state via agent.replaceMessages(sessionManager.buildSessionContext().messages)
Removed unused NewSessionOptions import

packages/coding-agent/src/modes/interactive/interactive-mode.ts

Simplified newSession handler to pass through options to AgentSession
Now calls renderInitialMessages() instead of hardcoding "✓ New session started" text
UI properly reflects any messages added via setup callback

packages/coding-agent/src/modes/rpc/rpc-mode.ts

Fixed same issue: removed manual setup handling, now passes options through to AgentSession

packages/coding-agent/CHANGELOG.md

Added fix entry under [Unreleased]

The fix ensures that when an extension calls ctx.newSession({ setup }) and appends messages in the setup callback, both the agent state and UI are properly synced without needing workarounds like calling navigateTree twice.

ok, how can i test this?

Create a minimal test extension:

Now run pi with the test extension:

Then test:

Run the command: Type /test-new-session and press Enter
Check UI: You should see the 4 messages (2 user, 2 assistant) rendered in the chat immediately, without needing any workarounds
Check LLM context: Type "What did we discuss?" and send. The LLM should know about the 2+2 and 3+3 conversation because the agent state was properly synced

Before the fix: The UI would show "✓ New session started" and the LLM wouldn't know about the messages (user had to call navigateTree twice as a workaround)

After the fix: Messages render immediately and LLM has full context

works perfectly fine, add changelog entry, commit and push

Done. Committed and pushed:

fix(coding-agent): sync agent state after newSession setup callback
Closes #968