ECC My setup guide. And the 10 commands that matter.

Two commands, 32 seconds

That's how long the install took in the test, from the first command to “Plugin is now active”. You type both commands in the Claude Code prompt, where you talk to Claude. Wait for the first one to finish before the second.

Plan, build, secure, test. What really happened.

Claude Code 2.1.280 (model Sonnet 5) with its own settings folder, ECC 2.2.3 freshly installed, and a small Flask app that collects waitlist signups. The app had problems planted on purpose: a fake API key in the code, SQL built by pasting text, an admin export with no login check. Every prompt below was typed for real. Times and numbers come from the session logs.

1

Say plan

1 min 18 s

/ecc:plan Add a confirmation email when someone joins the waitlistCopy

• It read the code first, then wrote the plan: requirements, four phases, risks, and one open question about which email provider to use.
• It spotted the hardcoded key in legacy/admin.py and planned to keep the email credentials in environment variables.
• Then it stopped on WAITING FOR CONFIRMATION (yes/no/modify). Files changed before the OK: zero.

2

Say build

1 min 25 s

yes, build itCopy

• Your reply to the plan, in the same session. The OK is what starts the build.
• It created mail.py, wired it into app.py and wrote tests/test_mail.py.
• Result: All 6 tests pass (1 existing + 5 new).

3

Say secure

4 min 47 s

secure it: use the security-reviewer agent on this project and fix what it findsCopy

• security-reviewer is one of ECC's 71 agents. You call it by name, in plain English.
• The agent's report: 11 findings, 4 critical, 2 high, 3 medium, 2 low. Claude fixed all 4 critical (SQL injection in two admin routes, the hardcoded key, the admin export with no login) and both high ones (debug mode, a weak key check). It left the 2 low ones and said why.
• Then it re-ran the tests (6 of 6 pass) and a smoke test: no key 403, wrong key 403, right key 200.
• On screen Claude wrote “3 critical”: it counted the two SQL injections as one. The agent's report lists four.

4

Say test

2 min 41 s

/ecc:test-coverageCopy

• It measured coverage first: 47%. Then it wrote 25 new tests across three files.
• One test failed. It fixed its own assertion and ran everything again: All 31 tests pass.
• Coverage 47% → 99%. A separate re-run outside Claude confirmed it: 185 statements, 2 missed.

Learn these ten first

ECC 2.2.3 ships 97 commands. These ten cover a normal day in Claude Code: plan, test, review, fix, stay safe, keep your context. Every name comes from ECC's commands folder, with its exact syntax. Type them in the Claude Code prompt.

Five things that trip people up

More GitHub stars than Linux

Affaan Mustafa started ECC on GitHub in January 2026 and is by far its top contributor: 1,757 commits, more than three times the next one (518). In under nine months it passed Linux (251,656 stars) and React (250,921).

Checked on GitHub on 12 Oct 2026.