[duyet]

What

anyr claude now tells Claude Code the model's real context window through CLAUDE_CODE_MAX_CONTEXT_TOKENS.

Why

Claude Code 2.1.304 keys its model metadata on Anthropic model ids. A third-party id is an unknown model, so it opens on the built-in 200,000-token default. minimax/minimax-m3.1-flash reported 200k in /context while the catalog and the website say 1,000,000.

The CLI already resolved the number from /v1/models and carried it on BuildToolEnvInput.context_window, but never handed it over. It set CLAUDE_CODE_AUTO_COMPACT_WINDOW, which is the auto-compact threshold, not the window.

How

One insert in build_tool_env in src/spawn.rs, inside the claude branch.

if !is_virtual_preset(input.model) {
    if let Some(window) = input.context_window.filter(|n| *n > 0) {
        env.insert("CLAUDE_CODE_MAX_CONTEXT_TOKENS".into(), window.to_string());
    }
}

Guardrails.

• An unknown window stays unset. Claude Code takes a declared value as a promise and sizes the session to it.
• A virtual preset keeps its own window. Its hop is picked per request, and anyrouter/auto[1m] already carries the suffix Claude Code reads.
• A window at or below 200,000 is still declared, so every surface agrees with the catalog.
• CLAUDE_CODE_AUTO_COMPACT_WINDOW is untouched. It is the threshold, not the window.

Verification

$ anyr claude --model minimax/minimax-m3.1-flash --dry-run
ANTHROPIC_MODEL=minimax/minimax-m3.1-flash
CLAUDE_CODE_AUTO_COMPACT_WINDOW=1000000
CLAUDE_CODE_MAX_CONTEXT_TOKENS=1000000

Against the same base URL and the same model.

$ claude -p "/context"
**Tokens:** 43.7k / 1m (4%)

Before the fix the same session reported 26.3k / 200k (13%).

Tests

The first commit adds the failing test, the second the fix.

• A concrete model with a 1,000,000 window declares 1000000.
• An unknown window leaves the key absent.
• A virtual preset leaves the key absent.
• A window of 128,000 declares 128000.

cargo test passes, 416 tests across the crate. cargo fmt --check is clean.

Fixes #100

🤖 Generated with Claude Code