feat(cli): exclude ChatGPT subscriptions from explicit promptCacheBreakpoint treatment

[chrarnoldus]

Summary

• Follow-up to feat(cli): set prompt cache breakpoints on stable prefix and user query before environment details #13022.
• Exclude ChatGPT subscriptions (e.g. ChatGPT Plus/Pro/Team/Enterprise OAuth connections with zero token cost or targeting chatgpt.com backend endpoints) from manual promptCacheBreakpoint: { mode: 'explicit' } treatment.
• Standard OpenAI API keys, Azure OpenAI, and Kilo Gateway continue to receive explicit prompt cache breakpoints for GPT-5.6+ models as introduced in feat(cli): set prompt cache breakpoints on stable prefix and user query before environment details #13022.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (3 files)

• .changeset/exclude-chatgpt-from-prompt-cache-breakpoint.md
• packages/opencode/src/provider/transform.ts
• packages/opencode/test/provider/transform.test.ts

Incremental review of 9b820d2 (since 2e5199a): the isChatGPTSubscription → isLikelyChatGPTSubscription simplification drops the chatgpt.com URL check and keeps only the zero-cost heuristic. Verified against the production mechanism: CodexAuthPlugin's models hook zeroes cost for every OAuth model under providerID: "openai", so ChatGPT subscription models are still excluded; the dropped URL branch only covered manual configs targeting the Codex backend endpoint, which requires OAuth (and thus zeroed cost) to function at all. The rename is applied consistently with no stale references, the removed endpoint test matches the removed branch, and the remaining zero-cost test exercises the real implementation. Changeset unchanged and user-facing. Note: the PR description still mentions the chatgpt.com endpoint check — worth a minor edit for accuracy, not blocking.

Previous Review Summary (commit 2e5199a)

Current summary above is authoritative. Previous snapshots are kept for context only.

Previous review (commit 2e5199a)

Status: No Issues Found | Recommendation: Merge

Files Reviewed (3 files)

• .changeset/exclude-chatgpt-from-prompt-cache-breakpoint.md
• packages/opencode/src/provider/transform.ts
• packages/opencode/test/provider/transform.test.ts

Verified the isChatGPTSubscription heuristic against the actual production mechanism: CodexAuthPlugin zeroes cost for OAuth models under providerID: "openai", and the chatgpt.com URL check covers direct backend endpoint configuration. The supportsPromptCacheBreakpoint(modelId) → (model) signature change is applied consistently at both call sites, existing positive coverage (standard API-key gpt-5.6 with non-zero cost) remains intact, and the new tests exercise the real implementation without mocks. Changeset is present and user-facing.

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_{Reviewed by kimi-k3 · Input: 35.5K · Output: 5.6K · Cached: 253.9K}

_{Review guidance: REVIEW.md from base branch main}

[passanger68]

I hope this is joke!