Guide · Scope creep

How to keep Claude Code, Cursor and Codex inside the task

Updated 15 Nov 2026 · 5 min read

You ask an AI agent to fix the profile page. It also "tidies" the billing module and renames a public API field. This is scope creep, and it is where most AI regressions come from.

The fix: make the scope explicit, then check it

Telling the agent "only touch the profile page" in a prompt helps, but nothing verifies it. The reliable pattern has two halves: declare which files the task may change, and compare what actually changed against that list, including anything the agent already committed.

npx stet-cli init
stet scope set "Fix profile page" --allow "src/profile/**,tests/profile/**"
# ...the agent works...
stet guard

Guarding 3 changed files · task: Fix profile page
  ✓ src/profile/Profile.tsx
  ✓ tests/profile/profile.test.ts
  ✗ src/billing/invoice.ts  out of scope

✗ 1 file outside scope or protected. Revert, or widen the scope on purpose.

Protected paths (migrations, CI config, secrets handling) can be flagged on every task via .stet/config.json. Uncommitted work from an earlier task is carried and ignored unless the agent changes it again.

Setup per tool

Tool	How the agent learns the scope
Claude Code	MCP: `claude mcp add stet -- npx -y stet-cli mcp`. The agent can read the scope (`stet_scope`) and run `stet_guard`, but cannot change the scope.
Cursor	MCP: add `stet` to `.cursor/mcp.json` with command `npx -y stet-cli mcp`.
Codex, GitHub Copilot, Windsurf, Gemini CLI	Read AGENTS.md, which Stet updates with the current task and allowed files.
ChatGPT, Claude.ai, Gemini chat	`stet context --files "src/profile/**"` copies the rules, scope and code to paste in.

Make it impossible to skip

stet hook install adds a pre-commit hook that blocks commits staging out-of-scope or protected files.
In CI: npx -y stet-cli guard --base origin/main fails a pull request that strays.
stet scope done --commit closes a task: guard and check, then commit only the task's files.

FAQ

What if the task really needs another file?

Widen the scope on purpose: set it again with the extra glob. The point is that a human decides, not the agent.

Does guard slow anything down?

No. It reads git and runs in well under a second.

Scope your next AI task

npx stet-cli init · Setup guide · Why rules files aren't enough →