Plan mode plans. It does not hold.
1. Plan mode is a conversation. Nemeris is a contract.
In Claude Code, plan mode shows you a plan and asks if it's OK. Then the agent works, and nothing holds it to the plan anymore: it can touch files it never mentioned, skip tests, say "done" without having run anything. You find out at the end, by reading the diff, if you read it. With Nemeris, the plan is signed by you and becomes the boundary: whatever falls outside it is refused, with the reason shown. Not "recommended". Refused.
2. Proof at every stage, not at the end.
Plan mode has no stages. Nemeris has 4, and the band refuses the next one until the previous one has shown its work, and refuses the commit until all 4 have. "It skipped the tests" is refused at the fourth stage's door: that stage closes only on checks that actually ran and passed.
3. A record that stays.
Plan mode leaves you the plan. Nemeris adds a receipt for each of the 4 stages, kept with the commit. What it read, what it filed, what it wrote and what it ran stays on your machine, where you can read it and see what was done.
4. Audit before the commit, included.
Plan mode does not check the code. Nemeris Audit goes through it 12 ways and says what it found, and Claude is sent to audit before it commits.
5. "I could build this myself."
Yes, you could. Claude Code lets anyone build their own checks. It takes months. Then you find, one by one, every shortcut the agent takes around them. Nemeris is already built, and already fixed after real problems. You pay once, for 1 computer, with updates included.
6. Who it is not for.
If you read every diff and run every test by hand, you don't need Nemeris. Nemeris is for anyone who lets the agent work on its own, or works on code they don't fully understand, and wants to know BEFORE the click, not after.