fix(cpa): 保留 Codex 和 Grok 的中途系统指令

[tbphp]

关联 Issue / Related Issue

暂无关联 Issue；修复 #631 引入的 Anthropic → Codex/Grok 兼容性回归。

变更内容 / Change Content

• Bug 修复 / Bug fix
• 新功能 / New feature
• 其他改动 / Other changes

Claude Code 的 Anthropic 请求包含中途 system 消息时，Codex/Grok 路径会在发送前返回 422。现在在调用 CPA 前将消息中的 system 映射为 developer，保留指令内容和会话位置，允许这类请求正常转换。

• 统一聊天与本地 token 计数的指令映射，覆盖流式和非流式请求；已有 developer、顶层 system、普通 user 提醒及原始请求不被改写。
• 保留其他渠道的有损转换拒绝规则，以及工具约束和 DeepSeek 思考检查。
• 补充实际出站内容的回归测试，验证多段指令、工具调用与结果的顺序及内容、思考配置、请求隔离，以及本地计数与执行提示的一致性。已有 gjson/sjson 依赖调整为直接依赖，版本不变。

验证：

• make check 通过。
• third_party/cpaembedded 中 go test -count=1 ./... 通过。
• 新增回归用例在修复前复现同一拒绝错误，修复后通过。
• 用户实测确认：Claude Code 使用 Anthropic 协议请求 Codex 账号的 GPT 模型正常。Grok 已通过自动化出站验证，未做真实账号联调。

兼容性：不新增配置或数据库迁移。本次未更新公开文档或发布说明。

自查清单 / Checklist

• 我已运行 make check，或在说明中写明无法运行的原因和未验证范围。 / I ran make check, or documented why it could not run and what remains unverified.
• 本 PR 范围聚焦，未包含无关改动。 / This PR is focused and contains no unrelated changes.
• 我已更新必要的公开文档或发布说明。 / I updated any required public documentation or release notes.
• 我已确认提交、日志和测试数据不包含敏感信息。 / I confirmed that commits, logs, and fixtures contain no sensitive data.
• 如适用，我已说明兼容性或数据迁移影响。 / Where applicable, I documented compatibility or data-migration impact.

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-12T12:58:08.998889Z	9543bd5	New commits

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• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: QUIET

Plan: Advanced

Run ID: 0e24ceb2-8dee-431f-af58-c502dfcff26c

📥 Commits

Reviewing files that changed from the base of the PR and between 7e6989e and 9543bd5.

📒 Files selected for processing (2)

• internal/execution/cpa/conversion_fidelity.go
• internal/execution/cpa/conversion_fidelity_test.go

Included review availability: Your plan provides up to 8 included reviews per hour; 6 remain after this review.

---

📝 Walkthrough

Walkthrough

本次修改将 gjson 和 sjson 声明为直接依赖。prepareConvertedInstructions 会为 Codex 和 Grok 的 Anthropic 请求将 system 消息改写为 developer 消息。Execute 和 ExecuteStream 使用更新后的请求规格。测试覆盖流式、非流式和 CountTokens 操作，并验证消息顺序、内容、reasoning.effort 及原始请求体保持不变。

Priority: ⬇️ Low

Merge Risk: ⚪ Minimal · up to 9543b

The instruction-role conversion is scoped to the intended Codex/Grok Anthropic paths and is covered for streaming, non-streaming, and token-count behavior.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 4 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Title check	✅ Passed	标题明确概括了主要修复内容，准确指出 Codex 和 Grok 的中途系统指令保留行为。
Description check	✅ Passed	描述覆盖关联问题、变更内容、测试验证、兼容性影响和自查清单。作者明确说明未更新公开文档或发布说明，其他必需信息完整。

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 7e6989e09b

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• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

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Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[coderabbitai]

🧹 Nitpick comments (1)

internal/execution/cpa/conversion_fidelity_test.go (1)

196-198: 🗄️ Data Integrity & Integration | 🔵 Trivial | ⚡ Quick win

验证工具结果内容。

当前测试只验证 input.9.call_id。如果转换器丢失或改写 "tool result"，测试仍会通过。

请同时断言 input.9.output。

建议修改

 					"input.7.call_id":        "call_lookup", "input.7.name": "lookup",
-					"input.8.content.0.text": "DURING_TOOL", "input.9.call_id": "call_lookup",
+					"input.8.content.0.text": "DURING_TOOL", "input.9.call_id": "call_lookup",
+					"input.9.output":         "tool result",

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: QUIET

Plan: Advanced

Run ID: d177453d-e8c7-436f-8b33-a490e6e22999

📥 Commits

Reviewing files that changed from the base of the PR and between 5b03d29 and 7e6989e.

📒 Files selected for processing (4)

• go.mod
• internal/execution/cpa/adapter.go
• internal/execution/cpa/conversion_fidelity.go
• internal/execution/cpa/conversion_fidelity_test.go

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

[tbphp]

关于 Docstring Coverage 的 80% 提示：仓库没有该比例门禁，关键转换逻辑已有必要说明，本次不按比例批量补充注释。