fix(server): force Claude 200k context when selected/(default)

[lostf1sh]

What Changed

Fixed Claude context window handling so T3 Code’s 200k selection actually disables Claude Code’s automatic 1M context upgrade.

When 1M is explicitly selected, T3 Code still uses the [1m] model suffix and clears the disable flag.

Why

When you start coding with Claude in t3code, 200k is selected by default, but this doesn’t work—the model automatically sets itself to a 1M context window. This fix involves adding the “CLAUDE_CODE_DISABLE_1M_CONTEXT=1” flag directly to the environment and running it; you can also switch between 1M and 200k during the conversation.

Before :

After:

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

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Note

Medium Risk
Changes runtime environment passed into Claude Code sessions based on the selected contextWindow, which can affect model behavior across all Claude sessions; covered by targeted adapter tests but still touches core provider session startup.

Overview
For Claude provider session startup, the adapter now derives the effective contextWindow selection from provider option descriptors and injects/removes CLAUDE_CODE_DISABLE_1M_CONTEXT in the SDK env to prevent Claude Code from auto-upgrading to 1M when 200k (the default) is intended.

Adds tests verifying: selecting 200k (and the default selection) sets the disable flag, and explicitly selecting 1m clears the flag even if the process environment had it set.

^{Reviewed by Cursor Bugbot for commit acb6057. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

Force 200k Claude context window by setting CLAUDE_CODE_DISABLE_1M_CONTEXT by default

• Adds resolveClaudeOneMillionContextDisabled in ClaudeAdapter.ts to check the contextWindow provider option: returns true (disable 1M) when the value is 200k or absent, and false when explicitly set to 1m.
• Adds withClaudeContextWindowEnvironment to conditionally set or remove CLAUDE_CODE_DISABLE_1M_CONTEXT in the env passed to Claude queries.
• When the user explicitly selects 1m context, the env variable is removed and [1m] is appended to the model name to override any process-level disable.
• Behavioral Change: CLAUDE_CODE_DISABLE_1M_CONTEXT=1 is now injected by default (200k is the default context window), overriding any external env that had previously enabled 1M context silently.

^{Macroscope summarized acb6057.}

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[macroscopeapp]

Approvability

Verdict: Needs human review

This PR changes the default Claude context window from 1M to 200k for all users, which is a significant runtime behavior change. While the implementation is clean and well-tested, changes affecting default application behavior warrant human review to confirm intent.

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