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How to keep CLAUDE.md and .cursorrules in sync

Keeping CLAUDE.md and .cursorrules in sync by hand drifts fast. Here is why, and how a shared context source keeps every tool's rules current across a team.

April 28, 2026Updated May 2026by BaseThread

If your team uses more than one AI coding tool, you have more than one context file. Claude Code reads a CLAUDE.md. Cursor reads its rules. Newer tools read an AGENTS.md. They all say roughly the same thing, and the moment one changes, the others are quietly wrong.

Keeping them in sync by hand is a losing game. Here is why it drifts, and the approach that actually keeps every tool current.

Why do these files drift apart?

Each file lives in one tool's world, maintained by hand:

  • They duplicate the same intent in three slightly different formats.
  • Updates are manual, so a change to one rarely lands in the others the same day.
  • They are per-repo, so a convention that should apply everywhere has to be copied into every repository.
  • They are per-person in practice, because not everyone edits them and not everyone has the latest.

The result is three sources of truth that disagree, which is worse than one, because now a tool can be confidently wrong. We compare the file formats themselves in AGENTS.md vs CLAUDE.md vs .cursorrules.

The honest place a single file is fine

A CLAUDE.md or .cursorrules is a good start, and for one developer in one repo with one tool, it is genuinely enough. The drift problem only shows up at the second tool and the second teammate. If that is not you yet, keep the file and move on. This post is for when it is.

The fix: one source, projected to every tool

Instead of maintaining N files, keep the conventions and decisions in one shared source and let each tool read from it over the Model Context Protocol:

  • The team curates the rules and decisions once, in one place.
  • Claude Code, Cursor, Windsurf, and the rest read the relevant slice over MCP at the start of a session.
  • A change lands once and reaches every tool, no per-file copy.
  • New repos and new hires inherit the same context automatically, instead of someone seeding three files by hand.

This is shared context for AI tools applied to the specific pain of rule files: one source of truth, projected, instead of many copies, maintained.

How to move off hand-synced files

  • Consolidate the rules scattered across your CLAUDE.md, .cursorrules, and AGENTS.md into one shared source.
  • Connect each tool over MCP so it reads that source instead of its local file.
  • Keep decisions there too, so tools stop relitigating choices the team already made, not just style rules.
  • Let it write back, so new decisions join the source as work happens rather than waiting for a manual file edit.

The quick test

Open your CLAUDE.md and your .cursorrules side by side. If they disagree, your tools are already getting different instructions. One source removes the question.

TL;DR

CLAUDE.md, .cursorrules, and AGENTS.md duplicate the same intent in per-tool, per-repo files that drift the moment one changes. A single file is fine for one dev and one tool; past that, keep the conventions and decisions in one shared source every tool reads over MCP, so a change lands once and reaches every tool, repo, and teammate, and new hires inherit it automatically.

One set of conventions and decisions, read by every AI tool, instead of files you sync by hand.

See the shared-source approach

Related reading

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