Constraints And Boundaries — Claude Code Guide

Constraints define the way of working

The goal says what must be obtained, while scope says where to work. Constraints limit the implementation method: they prohibit unnecessary dependencies, broad refactoring, incompatible changes, and leaving the permitted area.

Constraints can be technical and procedural: discover first, plan next, clarify ambiguities, and provide a final report.

Constraints for an end-to-end change

• do not break existing endpoint contracts;
• do not add new libraries;
• do not edit old unrelated migrations;
• if a schema change is needed, create one new migration;
• preserve old records without the new field;
• avoid a large-scale rewrite of RefundService;
• discover the current implementation before editing.

A process frame for Claude

## Constraints
- First check the schema and related files.
- Submit a short plan before editing.
- Ask questions if a requirement is ambiguous.
- Make the smallest necessary changes.
- Run relevant checks.
- Report changed files, results, and residual risks.

Signals that boundaries were violated

• a large diff appeared for a small feature;
• renames or formatting appeared outside the task;
• a dependency was added without a need;
• a public API was changed silently;
• an old migration unrelated to the task was fixed.
• an unverified assumption became part of the implementation.

Final boundary checklist

1. Goal describes a behavioral result.
2. Current and Desired behavior are separated and verifiable.
3. Scope covers the required end-to-end flow.
4. Non-goals name deliberately deferred changes.
5. Constraints define technical and procedural rules.
6. The diff, tests, and report confirm that boundaries were not violated.