RuleStack
Counted 08:17 UTC

Real files, at real paths, counted every night

RuleStack
Real files, at real paths, counted every nightCounted 08:17 UTCDiff two files
7,205instruction files1,198repositories visited4,189rows written36files changed8formats20section tags85stacksCounted 13 September 2026
AGENTS.md617 repos, 60.4%CLAUDE.md359 repos, 35.2%.cursor/rules/*.mdc310 repos, 30.4%.github/copilot-instructions.md190 repos, 18.6%.clinerules188 repos, 18.4%GEMINI.md48 repos, 4.7%.windsurf/rules/*.md38 repos, 3.7%.cursorrules36 repos, 3.5%

.github/copilot-instructions.md is in 190 repositories. The median one runs 494 words.

Two layers: one always-on repo file, plus optional glob-scoped instruction files. Lives under .github/ rather than the repo root, which is the tell that it is aimed at the GitHub platform surface as much as the editor.

GitHubGitHubvendorSince 2024-10-01All 520 indexed files
Measured

What the nightly counted in real repositories

Counted 13 September 2026
Repositories carrying it190 18.6% of the corpus
Files that write down a command47.1%
Files carrying a code block53.3%
Every night counted

Repositories carrying Copilot instructions, one column a night

24 nights stored
2026-08-01110 to 190 repositories2026-09-13
Asserted

What the documentation says this file can express

Read 1 August 2026
File.github/copilot-instructions.md
OwnerGitHub
Tools that read it3 tools
Glob targetingYes
ImportsNo
FrontmatterYes
Nested filesNo
User scopeNo

Read from the format’s own documentation and checked by hand. Capabilities are asserted; adoption is measured.

copilot-instructions.md is always in scope. Additional .github/instructions/*.instructions.md files load when their applyTo glob matches the open file.

GitHub CopilotGitHub CopilotGitHub CopilotCopilot coding agentVS CodeVS Code
What it does well
Reaches Copilot across the editor, github.com and the coding agent from one file
applyTo globs give per-path targeting without leaving the .github convention
What it cannot do
Copilot-only
No imports; shared text is copied between instruction files
Buried under .github/, so contributors discover it less often than a root file
Counted pairwise

Repositories that carry Copilot instructions and something else

Counted 13 September 2026

The percentage is of repositories carrying Copilot instructions, which is the number a “Copilot instructions versus something” search is really asking for.

AGENTS.md64.2%122 carry both, 19.8% the other wayCLAUDE.md35.3%67 carry both, 18.7% the other wayCursor rules28.4%54 carry both, 17.4% the other wayCline rules27.4%52 carry both, 27.7% the other wayWindsurf rules11.6%22 carry both, 57.9% the other wayGEMINI.md10.0%19 carry both, 39.6% the other way.cursorrules2.6%5 carry both, 13.9% the other way
The files

520 Copilot instructions files match in the corpus. These score highest.

All 520
NoRepository and pathCoversScoreChanged
001Pythonpytorch/pytorch.github/copilot-instructions.md100 /10023 days ago002JavaScriptlouislam/uptime-kuma.github/copilot-instructions.md100 /1001 month ago003HTMLColorlibHQ/gentelella.github/copilot-instructions.md100 /10013 days ago004TypeScriptchihebnabil/lovable-boilerplate.github/instructions/global.instructions.md100 /1001 month ago005HerringtonDarkholme/megarepo.github/copilot-instructions.md100 /1001 month ago006TypeScriptebyron357/LifeOS-Enterprise.github/copilot-instructions.md100 /10014 days ago007Pythonu9401066/academic-figures-mcp.github/copilot-instructions.md100 /10014 days ago008Pythonu9401066/academic-figures-mcpvscode-extension/resources/repo-assets/academic-figures/.github/copilot-instructions.md100 /10014 days ago009C#dotnet/roslyn.github/instructions/Compiler.instructions.md99 /10025 days ago010Rustrtk-ai/rtk.github/copilot-instructions.md97 /1001 month ago011Pythonhiyouga/LlamaFactory.github/copilot-instructions.md97 /1001 month ago012JavaScriptJCodesMore/ai-website-cloner-template.github/copilot-instructions.md97 /1001 month ago