6.1040 Fall 2026

Advice on selecting an LLM and coding harness

There’s a growing array of agentic coding and work tools. New models are released often. Releases, particularly from Anthropic and OpenAI, tend to leapfrog each other with new state of the art capabilities, only to be overtaken a short time later by another release. At the same time, all models and tools have their own unique strengths and weaknesses.

Currently, Anthropic’s Claude Code and OpenAI’s Codex are the most popular and capable tools. However, MIT does not provide students with free subscriptions to them. Parley’s $10/month of credits, via https://platform.parley.mit.edu/my-keys, can be used for the CLI versions of both, but will likely be depleted quickly.

We therefore recommend signing up for Google AI Pro’s free student plan, because Google offers this year-long plan for free and because we expect it to be a sufficient daily driver for the course. Please note, however, that it’s not hard to blow through usage limits. Balancing LLM usage with cost is a pervasive challenge in real-world software development today. It is your responsibility to be strategic with your usage and keep an eye on limits. Note: verifying with an MIT ID does not work because it does not have an expiration date; use a billing statement from MITPay instead, for example.

Below, we summarize what we view as the most promising free options for your use this semester.

(Note that we will follow up separately with $50 of Google API credits, which will be useful if you want AI-powered features inside of the software that you build in this course).

Google AI Pro — recommended

  • Free access: 12 months free for eligible US students
  • App version: Gemini for chat; Antigravity desktop app for agentic coding and work
  • CLI version: Antigravity CLI

ChatGPT Plus

  • Free access: Four months free for eligible US students
  • App version: ChatGPT for chat; Codex desktop app for agentic coding and work
  • CLI version: Codex CLI

ChatGPT student credits

  • Free access: $100 in Codex credits for eligible US and Canadian university students, including those with a free ChatGPT account. Expires after 12 months; cannot be used for API calls.
  • App version: Codex desktop app
  • CLI version: Codex CLI

MIT Parley

  • Free access: MIT chat access, plus $10/month in API credits for undergraduates
  • App version: Parley web app for chat, with a separate allowance from API usage
  • CLI version: Codex CLI or Claude Code, configured with a Parley API key

Note that Google AI Pro and ChatGPT Plus require a payment method and renew at $20/month after the free period. You may want to set yourself a reminder before renewal.