MiniMax M3.1 Flash in practice: tests and comparisons with DeepSeek V4.1 Flash

The author recommends M3.1 Flash for boring background agent jobs but not near production code without checking, citing $0.15 input, $0.60 output and $0.015 cached input per 1M tokens.

Hands-on: one prompt yielded a playable single-file rain-soaked city runner in 46 minutes; self-playtesting found the runner falling through stacked rooftops after a few hundred meters, fixed with a 30,000-step check passing 96/96 with zero console errors.

A hands-on test has M3.1 Flash build a multi-file 3D candy factory game in OpenCode — six machines, belts, economy, live charts, minimap and save/load — fixing its own bugs along the way, and it was fast.

Hands-on: given one prompt for a playable pixel adventure game, M3.1 Flash in MiniMax Code built it, playtested it in the built-in browser, iterated on gameplay and UI, and caught its own bugs; 400 free credits daily.

The author ran M3.1 Flash via API in DeepSeek Harness and mcode over long sessions, adding features one by one to build a code-only open-world FPS with no external assets, calling it a big step up from M3 and planning to spend the rest of the month's quota improving it.

A developer demos FlashDesk, a customer-support agent built with MiniMax M3.1 Flash that triages tickets and drafts replies, but cites only MiniMax's own speed and cost claims without independent results.

Given a small Python shop library with five planted bugs and one slow function, M3.1 Flash fixed all six with no hints, found a seventh, and cut a duplicate check from 23.8s to 0.01s, though it also changed unrequested behavior.

A single prompt had M3.1 Flash build a working 3D interior design app with drag-and-drop furniture, real-time materials and lighting, alongside claims of 200+ tok/s and 70% lower agentic costs.

After testing MiniMax M3.1 Flash, the author finds it sufficient for multi-turn tool calls, code audits and simple computer use at far lower cost, arguing cheap-model execution plus expensive-model review should be the default agent architecture.

On Questflow's finance-agent benchmark covering retrieval, metric calculation and multi-tool calls, MiniMax M3.1 Flash rises from 73.8% to 94.9%, a few points behind Claude Opus 5.5 and free, with the author arguing the bottleneck has shifted to system-level data and tooling.

On 44 auto-graded time-limited agent tasks, DeepSeek V4.1 Flash scored 40/44, GLM-5.3 37/44, GLM-5.3-Flash 33/44, and MiniMax M3.1 Flash 26/44 but with the best vision; low effort beat max for DeepSeek and GLM.

The author agrees DeepSeek V4.1 Flash is better than MiniMax M3.1 Flash for the most part, but wants to give M3.1 Flash a fair shot inside MiniMax Code (MiniMaxAgent) and report back.