MiniMax-M3: /anthropic endpoint reports 200K context instead of 1M — Claude Code compacts early

[kemaltachgulyyev-a11y]

Hi MiniMax team,

I'm using MiniMax-M3 via Claude Code with the Anthropic-compatible endpoint (api.minimax.io/anthropic).

Issue: Claude Code shows a 200K context window instead of M3's actual 1M, and triggers autocompact at ~167K.

Root cause: Your /anthropic compatibility layer appears to be returning 200K in the model metadata for MiniMax-M3 — likely inheriting Claude Sonnet's context_window value. Claude Code trusts this metadata and caps its budget accordingly, ignoring the actual 1M capability of M3.

Requested fix: Please update the model metadata returned by the /anthropic endpoint so that MiniMax-M3 reports:

context_window: 1000000

Config I'm using (for reference):
ANTHROPIC_BASE_URL: https://api.minimax.io/anthropic
ANTHROPIC_MODEL: MiniMax-M3

Thank you.

[MarkSchmitt]

I've also experienced the same problem with claude code (2.1.174).

Also there does not seem a way to override this in claude code ... only help might be disabling auto compaction as a stop gap measure... in the meantime I'm using claude code with Fable to plan big things and write a plan, implement with opencode and m3 ... which breaks my flow and eliminates auto-correction from a main agent spawning m3 minions, but m3 is pretty good, so it's not a deal breaker.

[Long0516]

好像是claudecode代码里面做了更改，除了特定的claude模型，上下文都是会卡256K

[Long0516]

因为我看后端没有收到请求，但是claudecode却报错502了

[noor-latif]

Cross-referencing: letta-ai/letta-code#3118 reports the same model (minimax-m3) failing on the OpenCode Go proxy when used with tool calling — but for a different reason: the built-in model definitions in letta-code (and several other tools: hermes-agent#35183, pi#4106) incorrectly set api: "anthropic-messages" and a baseUrl missing the trailing /v1, so requests are routed to an endpoint the proxy doesn't serve. Worth documenting on the OpenCode Go side that the proxy only exposes /v1/chat/completions for these models, not the Anthropic Messages format, to prevent other tools from making the same mistake.