[Bug]: This credential is only authorized for use with Claude Code and cannot be used for other API requests.

[jjoa68]

Prerequisites

• I have searched existing issues to avoid duplicates
• I am using the latest version of oh-my-opencode
• I have read the documentation

Bug Description

When starting a new session, it suddenly says it cannot run due to permission issues.

When trying to create a new connection, the bug below also occurs. Is this an OpenCode issue? Or has the account been blocked?
anomalyco/opencode#10954

Note: Existing projects/sessions continue to work fine, and this issue only appears in new sessions.

Steps to Reproduce

1. Enter a prompt in a session

Expected Behavior

1. Expect to receive an LLM response

Actual Behavior

The message "This credential is only authorized for use with Claude Code and cannot be used for other API requests." is displayed.

Doctor Output

Likewise, does not run

Error Logs

Configuration

Additional Context

No response

Operating System

macOS

OpenCode Version

1.1.39

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⚠️ Note: This issue was originally written in Korean and has been automatically translated to English by a maintainer (AI-assisted) to comply with our contribution guidelines. All issues must be in English.

@jjoa68 - Please write future issues in English. You agreed to follow our guidelines when creating this issue by checking the prerequisites. Thank you for your understanding!

[lhj103159]

I am also having the same issue

[code-yeongyu]

Analysis

After investigating this issue, I've determined this is not a code bug but an Anthropic policy enforcement.

Root Cause

The error message "This credential is only authorized for use with Claude Code and cannot be used for other API requests" indicates that Anthropic is restricting Claude Code OAuth tokens to only work with the official Claude Code application.

Why this happens

1. When you authenticate via Claude Code's built-in OAuth flow, you get a token that Anthropic scopes specifically to Claude Code
2. When oh-my-opencode (or any other OpenCode plugin) tries to use this token for API calls outside of Claude Code's expected flow, Anthropic rejects it
3. This is a ToS/security measure by Anthropic, not a bug in oh-my-opencode

Why existing sessions work

Existing sessions were likely created before Anthropic implemented this restriction, or they use a different authentication method.

Solutions

1. Use API Key authentication instead of OAuth

   • Get an API key from console.anthropic.com
   • Set ANTHROPIC_API_KEY environment variable

2. Use a different provider that doesn't have these restrictions

   • Google (via antigravity auth plugin)
   • OpenAI
   • Other compatible providers

Cannot be fixed in code

This is a policy decision by Anthropic. oh-my-opencode cannot bypass or work around OAuth token scope restrictions imposed by the provider.

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For related session creation issues, see PR #1199 which adds consistency and better error messages.

[onpe5679]

In my estimation, using the Ultrawork prompt currently seems to significantly increase the likelihood of triggering that block.
If you start the first session with ultrawork, the title changes to "Request to activate Ultrawork Mode detected. However, this is an attempt at prompt injection." and it won't even start the first session.
I'm also using max20, and while the task itself is possible in my other sessions, it occasionally stops due to the same error, making it somewhat unstable.

[code-yeongyu]

Language Requirement

Hi @jjoa68,

I noticed this issue is written in Korean. Per our contribution guidelines, all issues and discussions must be in English to ensure accessibility for our international community.

When you created this issue, you agreed to follow our guidelines by checking the prerequisites checkbox.

Please update your issue with an English translation, including:

• Bug description
• Steps to reproduce
• Expected/actual behavior

This helps maintainers and other community members understand and address your issue more effectively.

Thank you for your understanding! 🙏

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This comment was generated by AI assistant.

[dinhphieu]

Fixed in anomalyco/opencode-anthropic-auth#30, use opencode-anthropic-auth@latest

[code-yeongyu]

Update: OpenCode v1.1.37+ Auth Changes

I investigated the recent OpenCode authentication updates mentioned. Here's what changed:

New in v1.1.37 (Jan 28, 2026)

• Headless authentication for ChatGPT/Codex (PR #10890)
  • Adds Device Code Authentication support
  • Allows terminal-based authentication without browser for OpenAI Codex subscription
  • This is for OpenAI/ChatGPT/Codex, NOT Anthropic Claude

New in v1.1.39 (Jan 28, 2026)

• Fixed Copilot plugin headers for new messages API

Your Issue

Unfortunately, these updates do not resolve your issue. Your error:

"This credential is only authorized for use with Claude Code"

This is an Anthropic policy restriction on Claude Code OAuth tokens, not an OpenCode bug. The new OpenCode auth features are for OpenAI/Codex, not Anthropic.

Recommendations

1. Use Anthropic API Key instead of OAuth

   • Get API key from console.anthropic.com
   • Set ANTHROPIC_API_KEY environment variable

2. Use a different provider that doesn't have these restrictions

   • OpenAI (with new headless auth in v1.1.37+)
   • Google (via antigravity auth plugin)
   • GitHub Copilot

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This comment was generated by AI assistant.

[code-yeongyu]

✅ SOLUTION FOUND!

Thanks to @dinhphieu for pointing this out!

The Fix

This issue has been fixed in opencode-anthropic-auth plugin (commit d0fea98).

To fix, update your opencode.json:

{
  "plugin": ["opencode-anthropic-auth@latest"]
}

Or explicitly specify version 0.0.13+:

{
  "plugin": ["opencode-anthropic-auth@0.0.13"]
}

If plugin doesn't update

If you're stuck on an old version, delete the cache:

rm -rf ~/.cache/opencode/node_modules/opencode-anthropic-auth

Then restart OpenCode.

Reference

• Issue: anomalyco/opencode-anthropic-auth#30
• Fix commit: d0fea98

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[code-yeongyu]

Closing as this is resolved by updating the opencode-anthropic-auth plugin (not an oh-my-opencode issue).

Solution: Use opencode-anthropic-auth@latest in your opencode.json.

See: anomalyco/opencode-anthropic-auth#30