MiniMax-M3 emits truncated tool-call JSON (error 2013) and destroys resumable session

Bắt đầu với các đường dẫn runtime của phiên liên tục và việc gọi công cụ, sử dụng artifact chạy được giữ lại và lỗi provider đã được làm sạch làm điểm bắt đầu tái hiện. Thực hiện các bước tái hiện được liệt kê với MiniMax-M3 và so sánh hành vi khi việc sử dụng công cụ bị cấm rõ ràng. Được xem là hoàn tất khi JSON gọi công cụ không hợp lệ được xử lý mà không khiến phiên vĩnh viễn không thể tiếp tục, đồng thời có coverage cho đường dẫn lỗi của provider.

Summary

While using MiniMax-M3 through a persistent Codex/fast-subagent session, the model attempted an unrequested tool call whose arguments were truncated. The provider returned error 2013 (invalid_prompt), and the persistent session became structurally non-resumable.

Environment

• Date: 2026-08-09
• OS: Windows
• Model: MiniMax-M3
• Reasoning effort: high
• Runtime transport: Codex session wrapped by a local MCP supervisor
• MiniMax CLI was not used for the failing run

Sanitized failure

ERROR codex_core::tools::router: failed to parse function arguments:
EOF while parsing a string at line 1 column 260

provider response:
invalid params, invalid function arguments json string
code: invalid_prompt
numeric code: 2013

The last textual output before failure said the agent was going to write a research document, even though the requested outcome was a textual research list and no file write was requested.

A subsequent attempt to add a message to the same persistent session returned:

SESSION_NOT_RESUMABLE
Session cannot resume after structural failure in the previous run

Steps to reproduce

1. Start a persistent session with MiniMax-M3 and tool calling available.
2. Ask for a structured research response containing multiple candidates and URLs.
3. Let the model decide whether to invoke a tool.
4. In the observed run, the model emitted malformed/truncated JSON for a tool call.
5. Attempt to continue the same session.

I could not reproduce the malformed call in a clean second session after explicitly forbidding all tool use; that session completed normally. The original failure and non-resumable state are persisted and reproducible from its run artifact.

Expected behavior

• Tool-call arguments should always be valid complete JSON.
• If generation of a tool call fails, the provider/runtime should ideally return a recoverable turn error or allow the persistent session to continue.
• A malformed assistant tool call should not permanently destroy otherwise valid conversation state.

Actual behavior

• The turn exits with code 1 / provider error 2013.
• No token usage is returned for the failed run.
• The persistent session becomes structurally non-resumable.

No credentials, prompts containing personal data, or private file contents are included in this report.