FREE-TIER AI CODING CLI BRIEF — OCT 2026
==========================================
Compiled: 2026-10-28 | Sources: Superblocks (Aug 2026), Paradev (Oct 13 2026)
Lane: Draft — verifiable, cited, ready to ship.

1. THE LANDSCAPE IN TWO FACTS
-----------------------------
a) Only four major agents offer ANY free tier:
   - OpenAI Codex CLI (limited use via ChatGPT Free; Apache-2.0)
   - Google Antigravity CLI (weekly limits; proprietary)
   - GitHub Copilot CLI (free tier; proprietary)
   - Mistral Vibe (limited free tier; Apache-2.0)

b) The truly zero-cost path is open-source + bring-your-own-key:
   - OpenCode (MIT, 75+ providers, 214K GitHub stars as of Oct 2026)
   - Pi (MIT, any provider)
   - Hermes Agent (MIT, any provider)
   - Goose (Apache-2.0, 15+ providers)

2. HEAD-TO-HEAD: THE FREE-TIER RELEVANT ONES
--------------------------------------------
Tool            | Free tier? | License | Model lock-in | Notes
----------------|------------|---------|---------------|-------------------------------
Claude Code     | NO         | Proprietary | Anthropic only | $20/mo Pro, $100-200/mo Max; deepest reasoning
OpenAI Codex    | Limited    | Apache-2.0 | OpenAI only (plans) | Ships Rust CLI; Go $8/mo, Plus $20/mo
OpenCode        | Yes*       | MIT      | None          | 75+ providers; free; $0 if you bring a free/local model
Antigravity CLI | Yes        | Proprietary | Google + others | Weekly limits; free with Google account
Copilot CLI     | Yes        | Proprietary | Claude/GPT/Gemini/Grok/Kimi | $10/mo Pro; free tier included
Mistral Vibe    | Yes        | Apache-2.0 | Mistral + others | Free tier; Pro $14.99/mo
Hermes Agent    | Yes*       | MIT      | None          | Free open-source agent; any provider via Nous Portal

*BYOK = bring your own API key or run a local model. Tool is free; you pay the provider.

3. VERDICT FOR FREE-TIER / SOVEREIGN OPERATORS
----------------------------------------------
If you will not pay vendors and want terminal-native coding agents:
  1) OpenCode is the strongest zero-cost CLI — MIT, 75+ providers, subagents, TUI + IDE.
  2) Hermes Agent is equivalent for orchestration (MIT, any provider, subagents, worktrees).
  3) Codex CLI is the best "limited free" from a major lab, but model choice is restricted to OpenAI without an API key.
  4) Claude Code is excluded from the free tier entirely.

4. ACTIONABLE CHOICE MATRIX
---------------------------
Scenario                           | Pick
-----------------------------------|-------------------------------
Zero dollars, any model            | OpenCode or Hermes Agent
Zero dollars, Google ecosystem     | Antigravity CLI
Already paying for ChatGPT Plus    | Codex CLI
Already paying for GitHub Pro      | Copilot CLI
Deep reasoning, budget available   | Claude Code Pro ($20)

5. SOURCES
----------
- Superblocks, "9 Best Claude Code Alternatives I Compared for 2026", Aug 11 2026
  https://www.superblocks.com/blog/claude-code-alternative
- Paradev, "Best AI Coding Agents in 2026: Claude Code, Codex, Antigravity, and 15 More Compared",
  facts checked Oct 13 2026
  https://superset.sh/compare/best-coding-agents
