The ecosystem has converged on Markdown-based instruction files — but they diverge on activation philosophy. Here's the honest comparison as of April 2026.
| Tool | File location | Activation | Progressive loading |
|---|---|---|---|
| Claude Code | .claude/skills/* + CLAUDE.md |
Three-tier progressive disclosure | Yes (best-in-class) |
| Cursor | .cursor/rules/*.mdc |
Four modes (always/auto/agent/manual) | Yes |
| GitHub Copilot | .github/copilot-instructions.md |
Always + path globs + manual prompts | Partial (globs) |
| Windsurf | .windsurf/rules/*.md |
Four modes: always/manual/model-decision/glob | Yes |
| Continue.dev | .continue/rules/*.md |
alwaysApply + globs + description |
Yes |
| Cline | .clinerules/*.md |
UI toggle + path frontmatter | No |
| Aider | CONVENTIONS.md (any name) |
Manual via --read flag |
No |
| Codex CLI | AGENTS.md |
Always loaded, closest-wins hierarchy | Directory-based |
| Gemini CLI | GEMINI.md |
Always loaded + @imports + hierarchical |
Partial (sub-dir-lazy) |
| Roo / Kilo Code | .roo/rules/* + AGENTS.md |
Always-on per active mode | Via mode switching |
Supported natively by Codex, Cursor, Gemini CLI, Copilot, Windsurf, Continue.dev, Aider, and more — through a cross-tool convention stewarded by the Linux Foundation's Agentic AI Foundation. It is the closest thing to a cross-tool-ready "just works" file today.
Every other tool points at a single Markdown file. Claude Skills are folders in .claude/skills/ that can ship a SKILL.md alongside scripts, reference documents, and templates — which is what enables progressive disclosure of bundled files on demand.
Always Apply, Specific Files (globs), Intelligently (description-only), and Manually (@rule-name) — a granularity the rest of the ecosystem hasn't matched. Every other tool offers one or two of these, not all four.