Conversation history shows duplicate 'Warmup' titles and loads wrong conversations

Claude Code Bug Report: Conversation History Loading Issue

Summary

Conversation history UI displays duplicate "Warmup" titles for multiple distinct conversations, and selecting a specific conversation loads the wrong conversation content.

Environment

OS: Linux (WSL2) - Linux 6.6.87.2-microsoft-standard-WSL2
Claude Code Version: 2.0.17 (from ~/.vscode-server/extensions/anthropic.claude-code-2.0.17)
VSCode: Remote (WSL)
Working Directory: /home/hrothgarious/bke
Date of Issue: October 16, 2025

Expected Behavior

Each conversation in the history list should display a unique, descriptive title or first message
Selecting a conversation from the history should load that specific conversation
Different conversations should be distinguishable in the UI

Actual Behavior

Multiple distinct conversations all show "Warmup" as the title in the conversation history list
Selecting a specific conversation loads different/wrong conversation content
User cannot distinguish between conversations or reliably resume a previous conversation

Evidence from Filesystem

Conversation files are stored in ~/.claude/projects/-home-hrothgarious-bke/ as JSONL files.

Actual Conversations from Today (Oct 16):

1. File: `c7bc33e6-dd71-409e-9a42-c45b27c6789f.jsonl`

Size: 250KB
Messages: 69
Last Modified: 17:23
Actual First Message: "@medial_axis/curve_descriptor.py"
Topic: Curve analysis and splitting work
Shows in UI as: "Warmup" (incorrect)

2. File: `0d0d6579-39e9-4511-a347-9b3bb2319bb8.jsonl`

Size: 128KB
Messages: 87
Last Modified: 17:03
Topic: Grasshopper MCP forking and development
Shows in UI as: "Warmup" (incorrect)

3. File: `7cfe8332-8326-4c3c-aa76-fcf2b755eaf0.jsonl`

Size: 295KB
Messages: 210
Last Modified: 17:38 (current/ongoing)
Topic: GitHub MCP server installation discussion
Shows in UI as: "Warmup" (incorrect)

JSONL Structure

First line of each conversation file:

{
  "parentUuid": null,
  "isSidechain": true,
  "userType": "external",
  "cwd": "/home/hrothgarious/bke",
  "sessionId": "7cfe8332-8326-4c3c-aa76-fcf2b755eaf0",
  "version": "2.0.17",
  "gitBranch": "",
  "type": "user",
  "message": {
    "role": "user",
    "content": "Warmup"
  },
  "uuid": "4aeee286-9ecf-48e1-803a-0c7689c2a31e",
  "timestamp": "2025-10-16T14:00:03.919Z"
}

Root Cause Analysis

The issue appears to be that:

The conversation history UI is using the FIRST user message ("Warmup") as the conversation title
Many users type "Warmup" as their first message to initialize the session
The UI should either:
- Skip "Warmup" messages when determining conversation titles
- Use the second user message or a summary of the conversation
- Use timestamps or other metadata to disambiguate

Impact

Severity: High - Users lose access to their previous work
Frequency: Reproducible - Affects all conversations that start with "Warmup"
Data Loss: No actual data loss (files intact), but data is effectively inaccessible through the UI
Workaround: Access conversation JSONL files directly from filesystem (requires technical knowledge)

Steps to Reproduce

Start multiple conversation sessions
Begin each session with the message "Warmup"
Have substantive conversations with different topics
Close and reopen VSCode/Claude Code
Attempt to select a specific previous conversation from the history
Observe that:
- All conversations show "Warmup" as title
- Selecting a conversation may load wrong content

Suggested Fixes

Short-term: Skip common initialization messages ("Warmup", "Hello", etc.) when generating conversation titles
Medium-term: Use AI to generate descriptive titles from the first few substantial messages
Long-term:
- Add explicit conversation naming/titling feature
- Show timestamp + first non-trivial message
- Show file tree or code files discussed as subtitle/metadata

Additional Context

User reported:

"I recall I had two relatively long conversations today"
"I tried all conversation from today and I cannot find the one"
"when I select the right one the same warm up conversation comes along and this is wrong"

The user was unable to resume their work through the UI and required filesystem-level investigation to identify the correct conversation files.

Related Files

Conversation storage: ~/.claude/projects/-home-hrothgarious-bke/*.jsonl
Extension location: ~/.vscode-server/extensions/anthropic.claude-code-2.0.17

Contact

Issue can be reproduced in the environment described above. Conversation JSONL files available for inspection if needed for debugging.

I'd submitted a duplicate here. I can add that:

The issue occurs with the extension 2.0.19 as well
The issue occurs on Windows as well
The issue occurs whether the Haiku model is 3.5 or 4.5
When I launch the CLI that is bundled with the extension, the issue doesn't appear (or at least titles that are NOT "Warmup" show up for the conversations). Thus, perhaps the issue is specific to the extension and doesn't even apply to the CLI that is bundled with the extension.
I think the issue occurred for me without me using "Warmup" as the prompt, but that prompt somehow ended up replacing the prompts that I did use (at least for one-prompt conversations).

I have this issue too and imo I think some kind of agent setting is being overriden when haiku model got triggered. This also happens when I use agent sdk with fork_session=true, resume={session_id}

It's not that users start conversations with "Warmup"

It looks like Claude Code itself started sending a "Warmup" message from user side. Which in turn triggers assistant response of the sorts of "Hi, I'm Claude Code, ready to work on your project ..."

started happening on the day of haiku 4.5 release

My conversation history has been flooded by sessions named "Warmup" as well

This is happening for me as well. VSCode Plugin v2.0.21

Numerous conversations all starting with "Warmup" and then a confused Claude trying to figure out what you want to do. Completely wiped out a bunch of conversations.

Same problem here, I'm building a script to remove this files until they fixed.

Same issue on macOS

Environment:

macOS (Darwin 24.4.0)
Claude Agent SDK: 2.0.19, 2.0.21, 2.0.22 (all affected)
Last working version: 2.0.13 (October 16, 2025)
First broken session: October 17, 2025 @ 3:16 PM (SDK 2.0.19)

我也遇到了，这个影响很大

Same issue here. All my past conversations were deleted

Same here! MacOS.
First broken session: October 20, 2025
I saw the session, closed VS Code and opened another file and wanted to continue with the session and suddenly saw "Warmup" in all!

2.0.24 (Claude Code)

Can you please let us know the version you're seeing this in?

2.0.24

2.0.25 and this warmup still exists.

raw jsonl of an example chat:

{"type": "summary"}
{"type": "summary"}
{"uuid": "1", "parentUuid": null, "sessionId": "2", "timestamp": "2025-10-22T10:50:15.112Z", "type": "user", "message": {"role": "user", "content": "Warmup"}}
{"uuid": "3", "parentUuid": "1", "sessionId": "2", "timestamp": "2025-10-22T10:50:20.158Z", "type": "assistant", "message": {"role": "assistant", "content": [{"type": "text", "text": "I'm ready to assist you with the Conare project. I've reviewed the system instructions and understand:\n\n**Key principles I'll follow:**\n- Minimal, elegant code changes\n- Nuxt 4 pre-release structure (app/ for frontend, root for backend)\n- [TRUNCATED: 1170 chars total]"}]}}
{"type": "file-history-snapshot"}
{"uuid": "4", "parentUuid": null, "sessionId": "2", "timestamp": "2025-10-22T10:50:30.921Z", "type": "user", "message": {"role": "user", "content": "tf"}}

my first actual message was "tf"

Found the issue, fix inbound!

Found the issue, fix inbound!

thanks!

We just shipped a hotfix for this in v2.0.27. Apologies for the inconvenience. Let us know if you still run into it with the new update!

not sure if this fix was intended for VSCode extension only. but Claude still sends the same warmup messages

raw jsonl of the chat in 2.0.27:

{"type": "summary"}
{"type": "summary"}
{"type": "summary"}
{"uuid": "1", "parentUuid": null, "sessionId": "2", "timestamp": "2025-10-25T08:25:52.590Z", "type": "user", "message": {"role": "user", "content": "Warmup"}}
{"uuid": "3", "parentUuid": "1", "sessionId": "2", "timestamp": "2025-10-25T08:25:57.256Z", "type": "assistant", "message": {"role": "assistant", "content": [{"type": "text", "text": "I'm Claude Code, Anthropic's official CLI for Claude. I'm ready to help you navigate and explore this codebase efficiently.\n\n [TRUNCATED]"}]}}
{"type": "file-history-snapshot"}
{"uuid": "4", "parentUuid": null, "sessionId": "2", "timestamp": "2025-10-25T08:25:58.043Z", "type": "user", "message": {"role": "user", "content": "hello54321"}}
{"uuid": "5", "parentUuid": "4", "sessionId": "2", "timestamp": "2025-10-25T08:26:01.967Z", "type": "assistant", "message": {"role": "assistant", "content": [{"type": "text", "text": "Hello! I see your test message. The vibe-rules are loading correctly (I can see \"test1234\" and \"hello54321\" in the context).\n\nHow can I help you today?"}]}}

This keeps happening. would you guys open the issue please

This keeps happening. would you guys open the issue please

same to me

@hackyon-anthropic

@hackyon-anthropic can we get the issue re-opened please?

@FutureExcited

Can you check that you have updated and post screenshots of your issue?

@FutureExcited this gets sent but it shouldn't show up in your message history.

Double Warmup Sessions + No Summaries Generated

Just discovered that SDK v2.0.28 is creating TWO warmup phantom sessions on every initialization, not just one:

agent-{id1}.jsonl - Haiku 4.5 warmup
agent-{id2}.jsonl - Sonnet 4.5 warmup

Both created simultaneously (1ms apart) with isSidechain: true and marked with the same parent sessionId.

Impact during development:

Every app restart = 2 phantom sessions
Every hot reload = 2 more phantom sessions
After a few hours of dev work = hundreds of agent-*.jsonl files cluttering the sessions directory

Additional Impact - No Summaries:
Sessions initiated through the SDK are no longer generating conversation summaries. This breaks the ability to quickly identify and /resume conversations when switching between Claude CLI, VSCode extension, and SDK-based applications. All sessions just show as "New Session", <ide_opened_file>, or display the warmup message instead of meaningful summaries.

Workaround:
Auto-delete files matching agent-*.jsonl pattern when loading sessions:

// Filter and delete warmup phantom sessions
for (const file of files) {
  if (file.startsWith('agent-')) {
    fs.unlinkSync(path.join(sessionsDir, file));
  }
}

This matches the CLI's behavior of hiding warmup messages from users, but at the filesystem level.

Related: This appears to be related to Anthropic's fix for keeping warmup out of real conversations (from #9671), but creating separate phantom sessions causes its own problems - especially for SDK-based applications with frequent restarts during development.

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.

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Conversation history shows duplicate 'Warmup' titles and loads wrong conversations #9668

Claude Code Bug Report: Conversation History Loading Issue

Summary

Environment

Expected Behavior

Actual Behavior

Evidence from Filesystem

Actual Conversations from Today (Oct 16):

1. File: `c7bc33e6-dd71-409e-9a42-c45b27c6789f.jsonl`

2. File: `0d0d6579-39e9-4511-a347-9b3bb2319bb8.jsonl`

3. File: `7cfe8332-8326-4c3c-aa76-fcf2b755eaf0.jsonl`

JSONL Structure

Root Cause Analysis

Impact

Steps to Reproduce

Suggested Fixes

Additional Context

Related Files

Contact

11 remaining items

Double Warmup Sessions + No Summaries Generated

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Conversation history shows duplicate 'Warmup' titles and loads wrong conversations #9668

Description

Claude Code Bug Report: Conversation History Loading Issue

Summary

Environment

Expected Behavior

Actual Behavior

Evidence from Filesystem

Actual Conversations from Today (Oct 16):

1. File: c7bc33e6-dd71-409e-9a42-c45b27c6789f.jsonl

2. File: 0d0d6579-39e9-4511-a347-9b3bb2319bb8.jsonl

3. File: 7cfe8332-8326-4c3c-aa76-fcf2b755eaf0.jsonl

JSONL Structure

Root Cause Analysis

Impact

Steps to Reproduce

Suggested Fixes

Additional Context

Related Files

Contact

Activity

bluelight773 commented on Oct 16, 2025

sorryhyun commented on Oct 17, 2025

FutureExcited commented on Oct 17, 2025

QFrankQ commented on Oct 17, 2025

FredipusRex commented on Oct 17, 2025

arturogarciavw commented on Oct 17, 2025

allfadersup commented on Oct 19, 2025

Zhaoren1998 commented on Oct 20, 2025

eliasg52 commented on Oct 20, 2025

MikhailRatner commented on Oct 20, 2025

11 remaining items

BTankut commented on Oct 22, 2025

eliasg52 commented on Oct 22, 2025

FutureExcited commented on Oct 22, 2025

hackyon-anthropic commented on Oct 24, 2025

eliasg52 commented on Oct 24, 2025

hackyon-anthropic commented on Oct 24, 2025

FutureExcited commented on Oct 25, 2025

sorryhyun commented on Oct 25, 2025

eliasg52 commented on Oct 25, 2025

FutureExcited commented on Oct 27, 2025

hackyon-anthropic commented on Oct 27, 2025

allfadersup commented on Oct 28, 2025

Double Warmup Sessions + No Summaries Generated

github-actions commented on Nov 4, 2025

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1. File: `c7bc33e6-dd71-409e-9a42-c45b27c6789f.jsonl`

2. File: `0d0d6579-39e9-4511-a347-9b3bb2319bb8.jsonl`

3. File: `7cfe8332-8326-4c3c-aa76-fcf2b755eaf0.jsonl`