GitHub MCP authentication fails with valid token after restart

[brunokleinsharecare]

Description

The GitHub MCP integration was previously working but now reports
"Authentication Failed: Bad credentials" even when the token configured in
~/.kiro/settings/mcp.json is valid and has the correct scopes
(repo, workflow, read:org, gist).

Steps to Reproduce

1. Configure GitHub MCP server in ~/.kiro/settings/mcp.json with a valid classic PAT
2. Launch Kiro — GitHub MCP reports authentication error
3. Verified token is valid via curl https://api.github.com/user — returns correct user
4. Verified token has repo scope and can access private org repos
5. Removing and re-adding the config, or replacing with a fresh token, does not resolve it
6. The MCP server process itself starts correctly (npx @modelcontextprotocol/server-github
   runs fine with the same token outside of Kiro)

Environment

• kiro-cli version: 2.1.1
• OS: macOS Darwin 24.6.0
• MCP server: @modelcontextprotocol/server-github (stdio type)

Expected Behavior

GitHub MCP authenticates successfully with the configured token, as it did before.

Actual Behavior

Mcp error: -32603: Authentication Failed: Bad credentials