[Bug] Anthropic Max Pro Credentials Failing (Total Block + Billing Fallback)

[YosefHayim]

Description

I am encountering a critical issue where my Anthropic Max Pro subscription credentials are no longer being recognized.

The tool fails to use my subscription and instead falls back to the "Sisyphus" managed backend, which demands a separate payment method via https://opencode.ai/workspace/....

Error Messages

I am seeing two distinct error behaviors.

1. Total Credential Block (Even on simple messages):
Anthropic appears to have fingerprinted and blocked the client entirely.

User: hi
Error: This credential is only authorized for use with Claude Code and cannot be used for other API requests.

User: jo
Error: This credential is only authorized for use with Claude Code and cannot be used for other API requests.

2. Billing/Fallback Error:

▣  Sisyphus · claude-sonnet-4-5
No pant method. Add a payment method here: https://opencode.ai/workspace/...

Steps to Reproduce

1. Authenticate using claude login (Account has active Max Pro subscription).
2. Attempt to run a command or start a session in Opencode.
3. The system either rejects the token immediately (Error 400) or attempts to route through Sisyphus.

Environment

• Plan: Anthropic Max Pro
• OS: macOS

[iSolate77]

Anthropic is blocking oauth token use by third parties. See workarounds here: anomalyco/opencode#7410 (comment)

[YosefHayim]

Can you confirm it has been worked for you ?

[iSolate77]

Can you confirm it has been worked for you ?

Yes, it did. Just install the plugin and reauthenticate.
Use at your own risk though

[YosefHayim]

well i use it and its not working.. can u confirm again from ur end from now ?
check the form. a lot have commented this is not working anymore.

[copyx]

well i use it and its not working.. can u confirm again from ur end from now ? check the form. a lot have commented this is not working anymore.

It worked. but It's not working anymore unfortunately.
I used the workaround and it was successful.
But now, it's gone.

[oritwoen]

The fix for Claude's subscription will be in the next OpenCode bundled release (based on commits). Now, you need to manually add the plugin: opencode-anthropic-auth@0.0.8. Version 0.0.7 not work anymore.

[faction23]

Just going to chime in with some info here. Dax (opencode) said they will be looking at this over the next couple of weeks to try to sort out a permanent solution, but this is against Anthropic TOS. There IS a slight chance of getting banned using opencode (with oh my, or without, though I suspect some of the behaviors of oh my may trigger this a bit more since i used claude max for months with opencode, then got banned 2 weeks into using it with oh my). Also, Anthropic is now leaning hard on stopping non-TOS use of their plans, so it will be whack-a-mole with any workarounds.

A few others and I here were banned over the last few weeks, and had an issue here discussing it. It is not the auth layer itself triggering bans, but rather the abnormal behavior a third party harness like opencode with oh my generates that can trigger them. Thariq from Anthropic just clarified this here: https://x.com/trq212/status/2009689809875591565

He also states they tried to unban most users they think were hit by that over the last while, and that you might be able to get your account back if you dm him (if this was your cause).

[TomLucidor]

Ripe timing to start looking into OpenRouter diversification + local SLMs for smaller tasks. Diverse fallbacks would be sweet. #585