[andrewpark-scaleai]

Why

Claude Code run on a model that isn't Claude fails its first turn. On 11-11, starting about 22:00 UTC, every task-snapshot-hg4-with-gsuite-bundle-1174-*-glm-ts and -ds-ts run ended at its prompt step with:

claude CLI exited with code 1: API Error: 400 litellm.UnsupportedParamsError: fireworks_ai does not support parameters: ['context_management'], for model=accounts/fireworks/models/glm-5p3-flash

The CLI sends Anthropic's beta parameters whatever the model is. LiteLLM forwards a Fireworks model's request to Fireworks and refuses the parameters that provider doesn't take. The Claude Code 2.1.322 bump didn't cause this, because 2.1.280 sends context_management to a Fireworks model too. What's new is tasks running Claude Code on Fireworks models.

What

When the run's model isn't a Claude model (its name doesn't contain claude), cli_env sets CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1. That stops the CLI sending context_management and the other experimental betas. A value already set in the environment wins. Claude models keep every beta they get today.

Validation

I ran the real claude 2.1.322 against a local server that records each request, on fireworks_ai/glm-5p3-flash:

Environment	context_management in the body	anthropic-beta
without the flag (today)	yes	includes context-management-2025-06-27
cli_env with this change	no	claude-code-20250219,interleaved-thinking-2025-05-14,effort-2025-11-24
a Claude model (claude-sonnet-5-5)	yes, unchanged	unchanged

New unit tests cover a Fireworks model, a Claude model, a Bedrock Claude model, and an explicit setting winning. The Fireworks case fails on main. tst/unit/agents/claude_code: 280 passed.

Not verified: a run against the real LiteLLM proxy.

Confidence Score: 5/5

The PR appears safe to merge.

Summary

Sets CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1 for non-Claude models using a configured endpoint.

• Claude Code skips experimental betas for non-Claude models.

No actionable issues found. Request behavior against the real LiteLLM proxy remains unverified, as the author notes.

_{Reviews (1) · Last reviewed commit: "fix(agents): Claude Code sends no Anthro..." · Reviewed by Greptile}