[BUG] Extensions tab permanently breaks after installing a manifest_version 0.4 (uv) extension — getInstalledExtensionsWithState throws "TypeError: u._parse is not a function"
Open 💬 4 comments Opened Jul 15, 2026 by shade-gh
Preflight Checklist
- [x] I have searched existing issues and this hasn't been reported yet
- [x] This is a single bug report (please file separate reports for different bugs)
- [x] I am using the latest version of Claude Code
What's Wrong?
Environment
- Claude Desktop 1.21459.0 (MSIX), Windows 11 (win32 10.0.26200)
- Extension: "Massive Market Data" v1.0.11, directory id
ant.dir.gh.polygon.polygon-mcp-server
(manifest_version "0.4", server.type "uv")
Steps to reproduce
- Install "Massive Market Data" from the connectors directory.
- Open Settings → Extensions.
Actual behavior
Install completes successfully (main.log: UV 0.9.7 downloaded, venv created,
"Successfully installed extension … v1.0.11"). Afterwards the Extensions tab hangs
forever in a loading state. Renderer console shows an unhandled promise rejection:
Uncaught (in promise) Error: Error invoking remote method
'$eipc_message$_…_claude.settings_$_Extensions_$_getInstalledExtensionsWithState':
TypeError: u._parse is not a function
The tab stays broken across restarts until the extension directory under
%LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\Claude Extensions
is deleted manually and the app is killed via Task Manager.
Expected behavior
Listing installed extensions must not crash on a manifest the install path itself
accepted. If manifest_version 0.4 / server.type "uv" is unsupported in the settings
path, it should be rejected gracefully at install time, and one bad record must not
disable the entire Extensions UI.
Analysis
- Install path supports 0.4/uv (UV runtime setup succeeds); the state-listing IPC
handler apparently resolves a validation schema by manifest_version/server.type,
gets undefined for this manifest, and calls undefined._parse(...) → TypeError.
- Possibly related: directory entry id is still
ant.dir.gh.polygon.polygon-mcp-server
while the bundle inside is mcp_massive (Polygon→Massive rebrand); listing icon
resolution also fetches a wrong favicon (403 from an unrelated domain).
- Worked until 2026-07-14; broke when v1.0.11 (manifest 0.4/uv) was published.
Attachments: manifest.json, main.log excerpt (12:06:25–12:06:32), console screenshot
<img width="1328" height="99" alt="Image" src="https://github.com/user-attachments/assets/24a5203b-0a25-49d8-a293-a66c76a0751b" />
What Should Happen?
Extension should be installed regularly
Error Messages/Logs
2026-07-15 12:06:23 [info] Failed to set title bar overlay, this is probably expected
2026-07-15 12:06:23 [info] Failed to set title bar overlay, this is probably expected
2026-07-15 12:06:25 [info] Failed to set title bar overlay, this is probably expected
2026-07-15 12:06:25 [info] Failed to set title bar overlay, this is probably expected
2026-07-15 12:06:25 [info] [download:6] Starting download from https://claude.ai/api/organizations/147962a1-792c-4e50-9f37-dad30939fcea/dxt/extensions/ant.dir.gh.polygon.polygon-mcp-server/download
2026-07-15 12:06:25 [info] [download:6] Starting download from https://claude.ai/api/organizations/147962a1-792c-4e50-9f37-dad30939fcea/dxt/extensions/ant.dir.gh.polygon.polygon-mcp-server/download
2026-07-15 12:06:26 [warn] Installing unsigned extension from C:\Users\phiur\AppData\Local\Temp\dxt-download-44726985-5aa3-4e18-af7f-ab1ed045ad20.mcpb
2026-07-15 12:06:26 [warn] Installing unsigned extension from C:\Users\phiur\AppData\Local\Temp\dxt-download-44726985-5aa3-4e18-af7f-ab1ed045ad20.mcpb
2026-07-15 12:06:26 [info] Sending can_install request to https://claude.ai/api/organizations/147962a1-792c-4e50-9f37-dad30939fcea/dxt/can_install with 1 extensions: {
extensions: {
'ant.dir.gh.polygon.polygon-mcp-server': {
extension_id: 'ant.dir.gh.polygon.polygon-mcp-server',
file_hash: '88b3e347ad95b28ca23160d16ecca06e71711b5c97f2cb55bd8f9f9b6f8f1d45',
manifest: {
manifest_version: '0.4',
name: 'mcp_massive',
display_name: 'Massive Market Data',
version: '1.0.11',
description: 'Stocks, options & indices market data via Massive.com financial data API. Access real-time and historical prices, quotes, trades, and aggregates for equities, options contracts, ETFs, FX, crypto, and more.',
author: {
name: 'Massive',
email: 'support@massive.com',
url: 'https://massive.com'
},
repository: {
type: 'git',
url: 'https://github.com/massive-com/mcp_massive.git'
},
homepage: 'https://massive.com',
support: 'https://github.com/massive-com/mcp_massive/issues',
icon: 'assets/icon-massive-lightmode.png',
server: {
type: 'uv',
entry_point: 'entrypoint.py',
mcp_config: [Object]
},
tools: [ [Object], [Object], [Object], [Object], [length]: 4 ],
keywords: [
'finance', 'market-data',
'stocks', 'forex',
'crypto', 'options',
'futures', 'trading',
'api', [length]: 9
],
license: 'MIT',
privacy_policies: [ 'https://massive.com/legal/privacy', [length]: 1 ],
compatibility: { platforms: [Array], runtimes: [Object] },
user_config: { MASSIVE_API_KEY: [Object] }
},
signature_info: { status: 'unsigned' },
source: 'registry'
}
}
}
2026-07-15 12:06:26 [info] Sending can_install request to https://claude.ai/api/organizations/147962a1-792c-4e50-9f37-dad30939fcea/dxt/can_install with 1 extensions: {
extensions: {
'ant.dir.gh.polygon.polygon-mcp-server': {
extension_id: 'ant.dir.gh.polygon.polygon-mcp-server',
file_hash: '88b3e347ad95b28ca23160d16ecca06e71711b5c97f2cb55bd8f9f9b6f8f1d45',
manifest: {
manifest_version: '0.4',
name: 'mcp_massive',
display_name: 'Massive Market Data',
version: '1.0.11',
description: 'Stocks, options & indices market data via Massive.com financial data API. Access real-time and historical prices, quotes, trades, and aggregates for equities, options contracts, ETFs, FX, crypto, and more.',
author: {
name: 'Massive',
email: 'support@massive.com',
url: 'https://massive.com'
},
repository: {
type: 'git',
url: 'https://github.com/massive-com/mcp_massive.git'
},
homepage: 'https://massive.com',
support: 'https://github.com/massive-com/mcp_massive/issues',
icon: 'assets/icon-massive-lightmode.png',
server: {
type: 'uv',
entry_point: 'entrypoint.py',
mcp_config: [Object]
},
tools: [ [Object], [Object], [Object], [Object], [length]: 4 ],
keywords: [
'finance', 'market-data',
'stocks', 'forex',
'crypto', 'options',
'futures', 'trading',
'api', [length]: 9
],
license: 'MIT',
privacy_policies: [ 'https://massive.com/legal/privacy', [length]: 1 ],
compatibility: { platforms: [Array], runtimes: [Object] },
user_config: { MASSIVE_API_KEY: [Object] }
},
signature_info: { status: 'unsigned' },
source: 'registry'
}
}
}
2026-07-15 12:06:26 [info] can_install check completed: 1 extensions checked: [
{
extensionId: 'ant.dir.gh.polygon.polygon-mcp-server',
canInstall: true,
reason: undefined
},
[length]: 1
]
2026-07-15 12:06:26 [info] can_install check completed: 1 extensions checked: [
{
extensionId: 'ant.dir.gh.polygon.polygon-mcp-server',
canInstall: true,
reason: undefined
},
[length]: 1
]
2026-07-15 12:06:26 [info] [UV Runtime] Setting up UV environment for mcp_massive
2026-07-15 12:06:26 [info] [UV Runtime] Setting up UV environment for mcp_massive
2026-07-15 12:06:26 [info] [UV Discovery] Searching for system UV installation...
2026-07-15 12:06:26 [info] [UV Discovery] Searching for system UV installation...
2026-07-15 12:06:26 [info] [UV Discovery] System UV not found, downloading bundled version...
2026-07-15 12:06:26 [info] [UV Discovery] System UV not found, downloading bundled version...
2026-07-15 12:06:26 [info] [UV Discovery] Downloading UV 0.9.7 for win32-x64...
2026-07-15 12:06:26 [info] [UV Discovery] Downloading UV 0.9.7 for win32-x64...
2026-07-15 12:06:26 [info] [download:7] Starting download from https://github.com/astral-sh/uv/releases/download/0.9.7/uv-x86_64-pc-windows-msvc.zip
2026-07-15 12:06:26 [info] [download:7] Starting download from https://github.com/astral-sh/uv/releases/download/0.9.7/uv-x86_64-pc-windows-msvc.zip
2026-07-15 12:06:27 [info] [UV Discovery] ✓ Download verified successfully
2026-07-15 12:06:27 [info] [UV Discovery] ✓ Download verified successfully
2026-07-15 12:06:27 [info] [UV Discovery] ✓ UV binary installed to C:\Users\phiur\AppData\Roaming\Claude\uv-runtime\uv-0.9.7-win32-x64\uv.exe
2026-07-15 12:06:27 [info] [UV Discovery] ✓ UV binary installed to C:\Users\phiur\AppData\Roaming\Claude\uv-runtime\uv-0.9.7-win32-x64\uv.exe
2026-07-15 12:06:27 [info] [UV Runtime] Running uv sync to create venv and install dependencies
2026-07-15 12:06:27 [info] [UV Runtime] Running uv sync to create venv and install dependencies
2026-07-15 12:06:28 [warn] [event-loop-stall] main process blocked for 514ms (task none, total 23, cumulative 19819ms, rss 384MB)
2026-07-15 12:06:28 [warn] [event-loop-stall] main process blocked for 514ms (task none, total 23, cumulative 19819ms, rss 384MB)
2026-07-15 12:06:28 [info] [process-memory] trigger=stall tree_rss_sum=1352MB electron(7)=1352MB children(0)=0MB top=[electron_renderer:41516:407MB electron_main:35892:384MB electron_gpu:11576:175MB electron_utility:21432:131MB electron_utility:49412:99MB] sys_free=13497MB/32450MB sys_free_raw=13497MB
2026-07-15 12:06:28 [info] [process-memory] trigger=stall tree_rss_sum=1352MB electron(7)=1352MB children(0)=0MB top=[electron_renderer:41516:407MB electron_main:35892:384MB electron_gpu:11576:175MB electron_utility:21432:131MB electron_utility:49412:99MB] sys_free=13497MB/32450MB sys_free_raw=13497MB
2026-07-15 12:06:31 [info] [process-memory] trigger=interval tree_rss_sum=1343MB electron(7)=1343MB children(0)=0MB top=[electron_renderer:41516:402MB electron_main:35892:379MB electron_gpu:11576:176MB electron_utility:21432:131MB electron_utility:49412:99MB] sys_free=13049MB/32450MB sys_free_raw=13049MB
2026-07-15 12:06:31 [info] [process-memory] trigger=interval tree_rss_sum=1343MB electron(7)=1343MB children(0)=0MB top=[electron_renderer:41516:402MB electron_main:35892:379MB electron_gpu:11576:176MB electron_utility:21432:131MB electron_utility:49412:99MB] sys_free=13049MB/32450MB sys_free_raw=13049MB
2026-07-15 12:06:32 [info] [UV Runtime] ✓ Setup completed successfully
2026-07-15 12:06:32 [info] [UV Runtime] ✓ Setup completed successfully
2026-07-15 12:06:32 [info] Extension ant.dir.gh.polygon.polygon-mcp-server has missing required configuration, not enabling automatically
2026-07-15 12:06:32 [info] Extension ant.dir.gh.polygon.polygon-mcp-server has missing required configuration, not enabling automatically
2026-07-15 12:06:32 [info] Successfully installed extension ant.dir.gh.polygon.polygon-mcp-server v1.0.11
2026-07-15 12:06:32 [info] Successfully installed extension ant.dir.gh.polygon.polygon-mcp-server v1.0.11
2026-07-15 12:06:32 [info] Added metadata for extension ant.dir.gh.polygon.polygon-mcp-server
2026-07-15 12:06:32 [info] Added metadata for extension ant.dir.gh.polygon.polygon-mcp-serverSteps to Reproduce
see above (whats wrong)
Claude Model
Other
Is this a regression?
Yes, this worked in a previous version
Last Working Version
_No response_
Claude Code Version
1.21459.0
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
PowerShell
Additional Information
Side note: Autostart of CoworkVMService does not work correct, as long as this issue is persistent in the client. This can be repeatably solved by workaround: manually deleting the not working extension and its configuration and restarting everything.
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