AnthropicAWS.copy() rejects credentials=None, breaking the self-hosted environment poller/worker on Claude Platform on AWS

[csantanapr]

Summary

On Claude Platform on AWS, the self-hosted environment work helpers crash with a TypeError before making any request, because they build a Bearer-scoped sub-client that the AWS client's copy() cannot produce. This makes the self-hosted environment poller and worker unusable with AnthropicAWS / AsyncAnthropicAWS.

Affected version

Reproduced on the latest release, anthropic==0.116.0 (anthropic[aws]).

Root cause

anthropic/lib/_scoped_client.py::_copy_client_with_bearer_auth scopes a sub-client with:

scoped = client.copy(
    auth_token=auth_token,
    credentials=None,
    default_headers={STAINLESS_HELPER_HEADER: helper},
)

But AnthropicAWS.copy() / AsyncAnthropicAWS.copy() (in anthropic/lib/aws/_client.py) intentionally omit the credentials parameter, so the call raises:

TypeError: AsyncAnthropicAWS.copy() got an unexpected keyword argument 'credentials'

This helper is called by every self-hosted environment helper:

• resources/beta/environments/work.py::poller() (line ~1176)
• lib/environments/_worker.py::EnvironmentWorker (lines ~311, ~393)
• lib/tools/_beta_session_runner.py (line ~221)

so none of them work on the AWS platform.

Reproduction

import asyncio
from anthropic import AsyncAnthropicAWS

async def main():
    client = AsyncAnthropicAWS(
        aws_access_key="AKIAFAKE", aws_secret_key="fake",
        aws_region="us-west-2", workspace_id="wrkspc_example",
    )
    it = client.beta.environments.work.poller(
        environment_id="env_example",
        environment_key="unused-on-aws",  # required kwarg
        auto_stop=False,
    )
    async for _ in it:  # raises before the first poll
        break

asyncio.run(main())

Result:

File ".../anthropic/resources/beta/environments/work.py", line 1176, in poller
    scoped = _copy_client_with_bearer_auth(...)
File ".../anthropic/lib/_scoped_client.py", line 57, in _copy_client_with_bearer_auth
    scoped = client.copy(...)
TypeError: AsyncAnthropicAWS.copy() got an unexpected keyword argument 'credentials'

The same TypeError occurs via EnvironmentWorker(...).handle_item() on the AWS client.

Expected behavior

The environment poller/worker should work on Claude Platform on AWS. The AWS client authenticates with SigV4 (or an API key), so there is no token-provider credential to swap — copy(credentials=None) should be a no-op that returns a sub-client still signing with SigV4.

Proposed fix

Let the AWS copy() overrides accept credentials (no-op when None, error on a real provider). This fixes all four call sites at once and lives entirely in src/anthropic/lib/ (never regenerated). PR: I'll link it below.

Environment

• anthropic 0.116.0 with the aws extra (botocore 1.43.x)
• Python 3.12

[csantanapr]

Opened a PR with the fix + regression tests: #1737

[csantanapr]

For context: I'm an AWS Specialist Solutions Architect working with the AWS EKS service team. I hit this while testing the integration of a reference implementation for running Claude Managed Agents self-hosted environments on Amazon EKS as sandboxes, wiring the in-cluster poller/worker to authenticate to Claude Platform on AWS via SigV4 (EKS Pod Identity, cross-account role chaining). The poller crashed on its first work.poll() with this TypeError before any request went out — the AWS credential path itself was working, so the failure is purely the copy(credentials=...) incompatibility in the environment helpers.

[shannigan-ant]

Hi @csantanapr,

Thank you for flagging this! We're taking a look.