MCP error: missing authorization header
Why a protected remote MCP endpoint returns a missing authorization header error, and how to start the correct client authorization flow.
OPEN GUIDEMCP / AUTHORIZATION / PROVIDERS
Diagnose the boundary, not the guess.
Identify whether a failure belongs to MCP configuration, client authorization, OAuth callback handling, provider scopes, or the selected account connection.
Codex MCP authentication failed
Diagnose a failed Codex remote MCP login, clear stale authorization state, and verify Working Machines tool discovery safely.
OPEN GUIDEClaude Code cannot find an MCP server
Check Claude Code MCP scope, configuration, transport, and authorization when a configured remote server is not available.
OPEN GUIDEOAuth redirect URI mismatch during MCP authorization
Resolve an OAuth redirect URI mismatch without copying authorization codes, tokens, or provider credentials into prompts or URLs.
OPEN GUIDEProvider connection is missing a required scope
Diagnose a Working Machines provider action rejected because the connected account lacks a required OAuth scope or permission.
OPEN GUIDEONE CONNECTION. REAL WORK.
Give your agent software it can use.
Connect through MCP or explore the Agent App catalog and choose only the capabilities your workflow needs.