Issue with Invalid Token Format for MCP Endpoint

[Kishan Gupta]

Description: I am encountering an issue while trying to connect to the Atlassian MCP server using the mcp-remote tool. The server is returning the following error:

{"error":"invalid_token","error_description":"Invalid token format"}

Steps to Reproduce:

1. I configured the mcp-remote tool with the following settings:

   • Command: npx
   • Arguments:
     [

       "-y",

       "mcp-remote",

       "https://mcp.atlassian.com/v1/sse",

       "--header",

       "Authorization: Bearer ${Token}"

     ]

2. I ran the following command to test the connection:

   npx -y mcp-remote https://mcp.atlassian.com/v1/sse --header "Authorization: Bearer ${Token}"

3. I also tested the endpoint directly using curl:

   curl -X GET https://mcp.atlassian.com/v1/sse -H "Authorization: Bearer ${Token}"

Findings:

• The token is valid and includes both an access token and a refresh token. It is not expired and has a remaining lifespan of 3300 seconds.
• The client information was successfully retrieved.
• Despite this, the server returns the error {"error":"invalid_token","error_description":"Invalid token format"}.

Debug Logs: I have attached the debug logs generated using the --debug flag for your reference.

Request: Could you please help me understand why the token is being rejected and provide guidance on the correct token format or any additional requirements for accessing the endpoint?

Thank you for your assistance.

[Dr Valeri Colon (Connect Centric) · Accepted solution]

@Kishan Gupta That endpoint doesn’t accept OAuth tokens from your Atlassian account. The MCP server requires a signed MCP-specific token generated by an approved client, not the standard access/refresh token pair. Even valid Atlassian tokens will fail with “invalid_token.” There isn’t public access yet, so the connection won’t work until Atlassian publishes the supported auth flow.

[Tomislav Tobijas · Accepted solution]

Hmm @Kishan Gupta ,

This kind of error usually points to an issue with the token type, format, or maybe endpoint...

As this is a bit far from my domain, I'm going to move this to the appropriate app/forum group so maybe some other experts could chime in.

As this is a relatively new platform, have you maybe tried reaching out to Atlassian Support directly to see what their team has to say about it?

Cheers,
Tobi

[Sos Zakaryan]

Hi @Kishan Gupta , 

Try removing the --header "Authorization: Bearer ${Token}" and run the command without providing the header. The mcp-remote tool automatically creates a .mcp-auth folder where it stores credentials after the OAuth flow is completed.

On the first run, mcp-remote will open a browser for authentication. Once you complete the authentication and close the browser, it stores all necessary data in that folder. After that, you don’t need to manually provide authorization — it will automatically refresh the access token using the refresh token.