[Bug] ZCode 3.2.5 GLM-5.2 main turns fail with 1210 when many MCP tools are enabled

提交前确认 · Pre-submission checklist

• 我已搜索过现有 issue，确认这不是重复 / I searched existing issues and confirmed this isn't a duplicate.
• 我已阅读 CONTRIBUTING.md / I've read CONTRIBUTING.md.

问题类别 · Category

模型设置 / 切换 · Model config

涉及的 Agent 框架 · Agent framework

ZCode Agent（自研）

严重程度 · Severity

阻塞使用 · Blocking (无法使用核心功能 / core function unusable)

复现频率 · Reproducibility

必现 · Always

问题描述 · Description

After updating to ZCode 3.2.5 on Windows, normal ZCode Agent turns with built-in Z.ai Coding Plan + GLM-5.2 fail with error 1210: Invalid API parameter. Title generation with the same model succeeds, but the main agent turn fails.

复现步骤 · Steps to reproduce

1. Open ZCode 3.2.5 on Windows.
2. Use the built-in Z.ai Coding Plan provider.
3. Select GLM-5.2 with High thinking effort.
4. Start a new task in a workspace where multiple MCP/plugin tools are available.
5. Send a minimal prompt, for example: Responda apenas: OK.
6. Observe the turn fail with error 1210.

期望表现 · Expected behavior

The ZCode Agent should complete the main turn and answer the prompt normally.

实际表现 · Actual behavior

The request reaches the Z.ai Anthropic-compatible endpoint and returns an SSE response with business error 1210. The UI shows the turn as failed.

ZCode 版本 · ZCode version

3.2.5.2316

设备 / 系统 / 浏览器 · Device / OS / Browser

Windows 10.0.26200 x64; built-in provider builtin:zai-coding-plan; model GLM-5.2; endpoint family https://api.z.ai/api/anthropic/v1/messages; thinking effort High.

截图 / 录屏 / 日志 · Screenshots / Recordings / Logs

Original error: [1210][Invalid API parameter, please check the documentation.][202607040547459dcfd6ea7a4546f3] TraceID: cc79248d-89d8-40e0-b35e-427a1d4b62ea provider=builtin:zai-coding-plan provider_code=1210 model=GLM-5.2. A later reproduced failed request had provider log id 202607040618189616aef920614e8c. Sanitized local diagnostics: title request succeeds with same model and thinking settings, no tools, no streaming. Main agent request fails with stream=true, anthropic-beta mid-conversation-system-2026-04-07, a role=system message inside messages, and 161 tools from MCP/plugin connectors. A local workaround succeeded after removing the mid-conversation-system beta header, moving system messages to top-level system blocks, and filtering tools from 161 to 15 core coding tools.

Start by comparing the successful title request with the failing main agent request at the Z.ai Anthropic-compatible endpoint, focusing on streaming, system-message placement, the beta header, and the MCP/plugin tool list. Done means a normal GLM-5.2 main turn completes successfully in the reported Windows configuration without error 1210.