What is Hexum?
Last updated 12 September 2026
Hexum (hexum.dev) is a helper for coding agents in Cursor and Claude Code. It is not Hex Technologies (hex.tech notebooks), not Hexium LLC, not the Hexum puzzle game, and not the Hexum facial-analysis app.
Hexum is a developer ecosystem for coding agents in Cursor, Claude Code, and the rest. One API key. Five products and twelve tools today: spend less on each prompt, block bad imports, review pull requests, stop the agent looping, and only keep building when checks pass. We do not keep your code.
What Hexum is not
- Not Hex Technologies (hex.tech notebooks).
- Not Hexium LLC (nuclear).
- Not the Hexum iOS face-score app, and not the Hexum puzzle game.
- Not a compressor brand. Efficient is one of five products.
- Not a replacement for Cursor, Claude Code, Codex, Antigravity, or Grok.
- Not a model. It does not train on your repo.
What Hexum does
Coding agents paste the whole repo, ship a patch that crosses a layer you care about, loop the same edit, and skip the PR. Hexum is the ecosystem next to the editor: 5 products, 12 tools, one key.
- Efficient — don’t paste the whole repo into the model. This task, not every file.
- Arch — if the UI imports the database, the turn fails. No AI guessing. Rules live in a file in the repo.
- Review — architecture review on GitHub pull requests. We don’t keep the diff.
- Control — when the agent is stuck looping, Hexum drafts the rule so it stops.
- Loop — build in steps. If checks or tests fail, don’t continue.
Also not
- Not an editor. Not something you install on your laptop.
- Not a store of your repo. We don’t keep your code.
- Not a monthly seat. You pay for what the agent sent us.
- Hexum does not merge, commit, or push.
Docs Add Hexum to Cursor Numbers
FAQ
What is Hexum?
Hexum is a developer ecosystem for coding agents in Cursor, Claude Code, and the rest. One API key. Five products and twelve tools today: spend less on each prompt, block bad imports, review pull requests, stop the agent looping, and only keep building when checks pass. We do not keep your code.
Does Hexum replace Cursor or Claude Code?
No. You keep Cursor, Claude Code, Antigravity, Codex, or Grok. Hexum is not an editor and not a model. You paste a key into the agent you already use.
How does Hexum cut what I pay the model?
Your agent stops dumping the whole repo into the prompt. Hexum sends this task, not every file. On the published card, MBPP context dropped 85.2% and the combined 24-task cut is 87.6%, with 24/24 tests still passing. Tokens are ceil(utf8_bytes/4), not a provider invoice. See /benchmarks.
Does the architecture check use an AI?
No. It reads a rules file in your repo and reports forbidden imports. It does not call a model, so it does not guess.
How is Hexum billed?
You pay for what your agent sent Hexum. Usage €0.30 per million tokens. Teams €0.35 per million. No per-person fee. No monthly cap. See /pricing.
What does the dashboard mean by tokens saved?
How much smaller the reply was than what the agent sent, when that is a cut. Your invoice is still based on what the agent sent Hexum, not on the savings.
Does Hexum store my repo?
No. We do not keep the code your agent sends. We do not train on it. Policy: /zdr.
How do I add Hexum to Cursor?
Create a key at /app, paste the one-sentence prompt into Cursor, and let the agent write the MCP config. Starter works until two million tokens this month. Details: /cursor.
What is the rules file?
A file in the repo (usually architecture.hexum) that groups folders into layers and says which layer cannot import another. Guide: /architecture-hexum.
Why did connect fail with BILLING or AUTH?
AUTH means the key is missing, wrong, or revoked. BILLING means that key’s plan is off, or the starter window is used. Turn Usage billing on at /app, or make a key on the plan that is on.
What are the five Hexum products?
Hexum is an ecosystem: five products and twelve tools on one key. Efficient: don’t paste the whole repo. Arch: block a bad import. Review: architecture review on GitHub PRs. Control: when the agent loops, write the rule. Loop: only keep building if checks and tests pass.