Bedrock sessions now enforce a timeout on the AWS default credential provider chain resolution. The default is 60 seconds, configurable via CLAUDE_CODE_AWS_CHAIN_RESOLVE_TIMEOUT_MS.
Evidence
Credential chain timeout wrapper (search for "AWS default-chain credential resolve timed out" and "CLAUDE_CODE_AWS_CHAIN_RESOLVE_TIMEOUT_MS")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
