ATK - fetch action from MCP not working

[gotenxds]

Describe the bug
Hi, the fetch action from mcp action is not working, gives the error
"No tools found for the MCP server. Please run the server first." but the code lens and output both say that 63 tools have been found.

The output gives no errors, I can also confirm no network operation are taking place (according to the dev tools, my mcp server and oauth server).

The only hint is the console errors shown in vs code dev tools:

To Reproduce
Steps to reproduce the behavior:

1. Go to connect to MCP server - HTTP not SSE, via cimd.
2. Click on ATK: Fetch action from MCP
3. See error

Expected behavior
ATK action to work and ai.plugin.json to be correctly populated.

VS Code Extension Information (please complete the following information):

• Version: 1.123.0
• OS: Mac 26.5 (25F71)

[m365-agent-toolkit-assistant]

👋 Hi @gotenxds,

Thank you for reporting this issue! We want to let you know that:

⏱️ Our team will personally review your issue
🎯 You can expect a response within 2 business days

✨ This is an AI-generated initial response
🤖 AI-Generated Preliminary Analysis:

Classification: Bug — documented behavior says ATK: Fetch action from MCP should work after Start, but your report shows the server is discovered (64 tools) while fetch still sees none.

• Learn docs explicitly say: start the MCP server, then use ATK: Fetch action from MCP to select tools and populate ai-plugin.json【build-mcp-plugins#add-tools-from-the-mcp-server】.
• Your symptom is internally inconsistent: code lens/output report 64 tools, but fetch returns “No tools found”, and you saw no outbound network activity during fetch.
• I couldn’t find a duplicate in the searched repo yet; this looks newly reported.
• The stable changelog available in-repo does not mention an MCP fetch fix after the older 5.x entries, so a confirmed fixed version is unverified.

Upgrade check

• No verified changelog fix found in packages/vscode-extension/CHANGELOG.md.

What to do now:

1. Re-test on the latest ATK build available to you.
2. Share your .vscode/mcp.json (redacted), plus VS Code Developer Tools console stack trace text.
3. Confirm whether the MCP transport is streamable HTTP and whether auth is required.
4. As a workaround, manually author ai-plugin.json from the discovered tool list.

Useful links:

• No similar issues found in the searched repos.
• https://learn.microsoft.com/microsoft-365/copilot/extensibility/build-mcp-plugins#add-tools-from-the-mcp-server

If you want, I can help draft the exact repro details maintainers will need.

---

Note: This is an automated first response generated by AI. A human team member will review your issue and provide a more detailed response soon. We appreciate your patience!

[gotenxds]

👋 Hi @gotenxds,

Thank you for reporting this issue! We want to let you know that:

⏱️ Our team will personally review your issue 🎯 You can expect a response within 2 business days

✨ This is an AI-generated initial response 🤖 AI-Generated Preliminary Analysis:

Classification: Bug — documented behavior says ATK: Fetch action from MCP should work after Start, but your report shows the server is discovered (64 tools) while fetch still sees none.

• Learn docs explicitly say: start the MCP server, then use ATK: Fetch action from MCP to select tools and populate ai-plugin.json【build-mcp-plugins#add-tools-from-the-mcp-server】.
• Your symptom is internally inconsistent: code lens/output report 64 tools, but fetch returns “No tools found”, and you saw no outbound network activity during fetch.
• I couldn’t find a duplicate in the searched repo yet; this looks newly reported.
• The stable changelog available in-repo does not mention an MCP fetch fix after the older 5.x entries, so a confirmed fixed version is unverified.

Upgrade check

• No verified changelog fix found in packages/vscode-extension/CHANGELOG.md.

What to do now:

1. Re-test on the latest ATK build available to you.
2. Share your .vscode/mcp.json (redacted), plus VS Code Developer Tools console stack trace text.
3. Confirm whether the MCP transport is streamable HTTP and whether auth is required.
4. As a workaround, manually author ai-plugin.json from the discovered tool list.

Useful links:

• No similar issues found in the searched repos.
• https://learn.microsoft.com/microsoft-365/copilot/extensibility/build-mcp-plugins#add-tools-from-the-mcp-server

If you want, I can help draft the exact repro details maintainers will need.

Note: This is an automated first response generated by AI. A human team member will review your issue and provide a more detailed response soon. We appreciate your patience!

1. Already at latest
2. I can share but it wont be useful without a way to login.
3. As stated in the ticket, HTTP not SSE
4. Will for now but we cant do this everytime we need to publish a change...

[Alive-Fish]

Hi @gotenxds , thanks for your report. I tried the VSC v6.10.1 and it worked well for the MCP server https://learn.microsoft.com/api/mcp. The tools have been fetched succussfully. ATK is using https://github.com/microsoft/vscode/blob/50bf27be5789ef1e1235a546cd46923085dba7c9/src/vscode-dts/vscode.proposed.mcpServerDefinitions.d.ts#L86 to fetch the tool list by VS Code API. If you still have the issue, I will create a ticket on microsoft/vscode but might need your information.

Could you try other MCP servers and did they meet the same issue? Or is it possible for us to try the MCP server that you used?

Cc. @sebastienlevert

[gotenxds]

Hi @Alive-Fish thanks for the response, I tried this with github mcp before posting this to make sure it's unrelated to our mcp, and I now tried it with the mcp your provided to the same result

I also tried removing vs code redownloading the latest version from the website and installing it again.
I tried the latest and also beta versions of the ATK plugin.

I'l provide what ever info I can just let me know what you need

[Nitin2108]

Hi @Alive-Fish i am also facing similar issue. My VSCODE version is : 1.123.0. i am using mac system. Could you please help me to fix the issue at earliest. Let me know if you need more information.

[Alive-Fish]

Thanks for your supplement. It seems the VS Code proposed API vscode.lm.startMcpGateway on MAC has issues. Let us have a try and see what happened.

[Nitin2108]

@Alive-Fish Please post a link if you create a ticket in vscode repo for this issue. This is bit urgent so i am requesting you to look into this on priority.

[gotenxds]

Glad you could find the issue @Alive-Fish, appreciate the quick PR, when pushed I'l verify and comment here, thank you.