{
 "title": "State of agent markdown, September 2026",
 "url": "https://markdownregistry.com/reports/state-of-agent-markdown-2026-09",
 "definitions": {
  "observed": "files first indexed at least 14 days before the data was frozen",
  "within7": "of those, files with an upstream commit dated within 7 days after first indexing (a lower bound)",
  "within14": "the same within 14 days (a lower bound); the page's change figure",
  "rest_files": "observed files outside the 10 repositories of that kind with the most changes within 14 days",
  "rest_w14": "within14 for those files",
  "cross_repo_dup": "files of at least 200 bytes whose bytes equal a file in another repository; the page's copy figure",
  "copy_repos": "repositories holding at least one such copy",
  "top4_copies": "copies held by the four repositories holding the most",
  "distinct_contents": "NOT used on the page: distinct SHA-256 contents among the live files of that kind",
  "drift_repos": "NOT used on the page: repositories with at least one observed file of that kind",
  "changed": "NOT used on the page: files with any commit after first indexing, over each file's whole, unequal watch period",
  "changed3": "NOT used on the page: files with three or more such commits, same unequal period",
  "dup_files": "NOT the page's copy definition: files with any byte-identical twin, same repository and any size included",
  "vendored.current": "files in other repositories byte-identical to the current recorded upstream version",
  "vendored.older": "files in other repositories byte-identical to an older recorded upstream version",
  "vendored.other": "files sharing the skill's name that match no recorded upstream version; left out of the page's figures"
 },
 "cite": "markdownregistry, \"State of agent markdown, September 2026\", September 27, 2026, https://markdownregistry.com/reports/state-of-agent-markdown-2026-09",
 "findings": [
  {
   "id": "drift",
   "text": "In the registry's corpus, roughly one in five agent markdown files changed within two weeks of being indexed. Of 47,724 files watched for at least 14 days, at least 9,487 (19.9%) received a new upstream commit within 14 days and at least 6,745 (14.1%) within 7. Without the ten most active repositories of each kind, the 14 day share is at least 17.8%."
  },
  {
   "id": "drift-kind",
   "text": "In the corpus, llms.txt files changed most often: at least 41.2% (106 of 257) changed within 14 days, followed by AGENTS.md at 27.8%, CLAUDE.md at 23.2%, SKILL.md at 19.4%, Cursor rules at 12.2%, DESIGN.md at 5.4%, each a lower bound."
  },
  {
   "id": "vendored",
   "text": "In the registry, copies of Anthropic's skills can fall behind their source. For 5 skills from the anthropics/skills repository (skill-creator, frontend-design, docx, pptx and xlsx), chosen because they change often, 75 files in other repositories are byte-for-byte copies of a recorded upstream version, and 47 of them (62.7%) match an older version rather than the current one."
  },
  {
   "id": "spec",
   "text": "About one in ten SKILL.md files in the registry breaks the Agent Skills specification's frontmatter rules. Of 60,844 SKILL.md files inside a skill directory, 54,836 (90.1%) conform; the most common failure is a name that does not match its directory (3,858 files, 6.3%)."
  },
  {
   "id": "critical",
   "text": "The audit flags 194 of 69,119 files (0.3%) on at least one critical check. The checks are deliberately broad, so emoji joiners, stray zero-width spaces, Persian text, the example access key from Amazon's documentation, code that reads environment variables, security guidance that quotes an attack and security test fixtures trip them too; a flag means read this file, not that it is malicious."
  },
  {
   "id": "pipe",
   "text": "In the registry, 458 files contain a curl or wget command piped straight into a shell, 395 of them SKILL.md files."
  },
  {
   "id": "copies",
   "text": "In the registry, 5.7% of SKILL.md files (3,487 of 61,170, across 254 repositories) are byte-identical to a file in another repository. DESIGN.md reads 53.3%, but 540 of its 555 copies sit in four repositories that carry the same template set."
  }
 ],
 "data": {
  "slug": "2026-09",
  "frozen_at": "2026-09-27T17:07:00Z",
  "corpus": {
   "artifacts": 69119,
   "repos": 2887,
   "owners": 2607,
   "versions": 214457,
   "first_crawl": "2026-09-05T21:32:54.928Z"
  },
  "window_days": {
   "min_days": 14,
   "max_days": 21.8
  },
  "removed_in_cohort": 1696,
  "kinds": [
   {
    "kind": "skill",
    "n": 61170,
    "a": 57008,
    "b": 2946,
    "c": 1042,
    "f": 174,
    "observed": 42581,
    "changed": 9350,
    "within7": 5864,
    "within14": 8272,
    "changed3": 2609,
    "dup_files": 9074,
    "cross_repo_dup": 3487,
    "copy_repos": 254,
    "top4_copies": 602,
    "drift_repos": 1633,
    "rest_files": 40986,
    "rest_w14": 7176,
    "distinct_contents": 55931
   },
   {
    "kind": "agents",
    "n": 3901,
    "a": 3570,
    "b": 316,
    "c": 6,
    "f": 9,
    "observed": 2623,
    "changed": 836,
    "within7": 512,
    "within14": 730,
    "changed3": 365,
    "dup_files": 628,
    "cross_repo_dup": 403,
    "copy_repos": 85,
    "top4_copies": 188,
    "drift_repos": 856,
    "rest_files": 1920,
    "rest_w14": 477,
    "distinct_contents": 3518
   },
   {
    "kind": "claude",
    "n": 2081,
    "a": 1387,
    "b": 682,
    "c": 6,
    "f": 6,
    "observed": 1333,
    "changed": 354,
    "within7": 240,
    "within14": 309,
    "changed3": 167,
    "dup_files": 590,
    "cross_repo_dup": 40,
    "copy_repos": 24,
    "top4_copies": 20,
    "drift_repos": 749,
    "rest_files": 1236,
    "rest_w14": 259,
    "distinct_contents": 1596
   },
   {
    "kind": "design",
    "n": 1042,
    "a": 1025,
    "b": 15,
    "c": 1,
    "f": 1,
    "observed": 634,
    "changed": 36,
    "within7": 27,
    "within14": 34,
    "changed3": 16,
    "dup_files": 571,
    "cross_repo_dup": 555,
    "copy_repos": 17,
    "top4_copies": 540,
    "drift_repos": 122,
    "rest_files": 518,
    "rest_w14": 20,
    "distinct_contents": 632
   },
   {
    "kind": "rules",
    "n": 510,
    "a": 460,
    "b": 48,
    "c": 0,
    "f": 2,
    "observed": 296,
    "changed": 44,
    "within7": 22,
    "within14": 36,
    "changed3": 5,
    "dup_files": 22,
    "cross_repo_dup": 14,
    "copy_repos": 4,
    "top4_copies": 14,
    "drift_repos": 76,
    "rest_files": 204,
    "rest_w14": 5,
    "distinct_contents": 500
   },
   {
    "kind": "llmstxt",
    "n": 415,
    "a": 351,
    "b": 54,
    "c": 8,
    "f": 2,
    "observed": 257,
    "changed": 112,
    "within7": 80,
    "within14": 106,
    "changed3": 71,
    "dup_files": 46,
    "cross_repo_dup": 16,
    "copy_repos": 10,
    "top4_copies": 10,
    "drift_repos": 190,
    "rest_files": 235,
    "rest_w14": 85,
    "distinct_contents": 392
   }
  ],
  "spec": {
   "n": 60844,
   "no_name": 1244,
   "no_description": 979,
   "bad_name": 1327,
   "name_not_dir": 3858,
   "long_description": 601,
   "conforming": 54836
  },
  "checks": [
   {
    "kind": "agents",
    "check_id": "base64",
    "failing": 1
   },
   {
    "kind": "agents",
    "check_id": "credential_exfil",
    "failing": 0
   },
   {
    "kind": "agents",
    "check_id": "credential_read",
    "failing": 22
   },
   {
    "kind": "agents",
    "check_id": "exfil_hosts",
    "failing": 0
   },
   {
    "kind": "agents",
    "check_id": "hidden_comment",
    "failing": 0
   },
   {
    "kind": "agents",
    "check_id": "hidden_style",
    "failing": 2
   },
   {
    "kind": "agents",
    "check_id": "injection",
    "failing": 6
   },
   {
    "kind": "agents",
    "check_id": "pipe_to_shell",
    "failing": 22
   },
   {
    "kind": "agents",
    "check_id": "raw_ip",
    "failing": 36
   },
   {
    "kind": "agents",
    "check_id": "rm_rf",
    "failing": 3
   },
   {
    "kind": "agents",
    "check_id": "script_tag",
    "failing": 58
   },
   {
    "kind": "agents",
    "check_id": "secret_shapes",
    "failing": 0
   },
   {
    "kind": "agents",
    "check_id": "size",
    "failing": 186
   },
   {
    "kind": "agents",
    "check_id": "zero_width",
    "failing": 7
   },
   {
    "kind": "claude",
    "check_id": "base64",
    "failing": 0
   },
   {
    "kind": "claude",
    "check_id": "credential_exfil",
    "failing": 1
   },
   {
    "kind": "claude",
    "check_id": "credential_read",
    "failing": 12
   },
   {
    "kind": "claude",
    "check_id": "exfil_hosts",
    "failing": 0
   },
   {
    "kind": "claude",
    "check_id": "hidden_comment",
    "failing": 1
   },
   {
    "kind": "claude",
    "check_id": "hidden_style",
    "failing": 0
   },
   {
    "kind": "claude",
    "check_id": "injection",
    "failing": 4
   },
   {
    "kind": "claude",
    "check_id": "pipe_to_shell",
    "failing": 14
   },
   {
    "kind": "claude",
    "check_id": "raw_ip",
    "failing": 22
   },
   {
    "kind": "claude",
    "check_id": "rm_rf",
    "failing": 3
   },
   {
    "kind": "claude",
    "check_id": "script_tag",
    "failing": 36
   },
   {
    "kind": "claude",
    "check_id": "secret_shapes",
    "failing": 0
   },
   {
    "kind": "claude",
    "check_id": "size",
    "failing": 604
   },
   {
    "kind": "claude",
    "check_id": "zero_width",
    "failing": 4
   },
   {
    "kind": "design",
    "check_id": "base64",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "credential_exfil",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "credential_read",
    "failing": 2
   },
   {
    "kind": "design",
    "check_id": "exfil_hosts",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "hidden_comment",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "hidden_style",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "injection",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "pipe_to_shell",
    "failing": 5
   },
   {
    "kind": "design",
    "check_id": "raw_ip",
    "failing": 4
   },
   {
    "kind": "design",
    "check_id": "rm_rf",
    "failing": 1
   },
   {
    "kind": "design",
    "check_id": "script_tag",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "secret_shapes",
    "failing": 0
   },
   {
    "kind": "design",
    "check_id": "size",
    "failing": 6
   },
   {
    "kind": "design",
    "check_id": "zero_width",
    "failing": 1
   },
   {
    "kind": "llmstxt",
    "check_id": "base64",
    "failing": 0
   },
   {
    "kind": "llmstxt",
    "check_id": "credential_exfil",
    "failing": 0
   },
   {
    "kind": "llmstxt",
    "check_id": "credential_read",
    "failing": 3
   },
   {
    "kind": "llmstxt",
    "check_id": "exfil_hosts",
    "failing": 1
   },
   {
    "kind": "llmstxt",
    "check_id": "hidden_comment",
    "failing": 0
   },
   {
    "kind": "llmstxt",
    "check_id": "hidden_style",
    "failing": 1
   },
   {
    "kind": "llmstxt",
    "check_id": "injection",
    "failing": 1
   },
   {
    "kind": "llmstxt",
    "check_id": "pipe_to_shell",
    "failing": 22
   },
   {
    "kind": "llmstxt",
    "check_id": "raw_ip",
    "failing": 18
   },
   {
    "kind": "llmstxt",
    "check_id": "rm_rf",
    "failing": 1
   },
   {
    "kind": "llmstxt",
    "check_id": "script_tag",
    "failing": 8
   },
   {
    "kind": "llmstxt",
    "check_id": "secret_shapes",
    "failing": 0
   },
   {
    "kind": "llmstxt",
    "check_id": "size",
    "failing": 25
   },
   {
    "kind": "llmstxt",
    "check_id": "zero_width",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "base64",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "credential_exfil",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "credential_read",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "exfil_hosts",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "hidden_comment",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "hidden_style",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "injection",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "pipe_to_shell",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "raw_ip",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "rm_rf",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "script_tag",
    "failing": 3
   },
   {
    "kind": "rules",
    "check_id": "secret_shapes",
    "failing": 0
   },
   {
    "kind": "rules",
    "check_id": "size",
    "failing": 45
   },
   {
    "kind": "rules",
    "check_id": "zero_width",
    "failing": 2
   },
   {
    "kind": "skill",
    "check_id": "base64",
    "failing": 34
   },
   {
    "kind": "skill",
    "check_id": "credential_exfil",
    "failing": 30
   },
   {
    "kind": "skill",
    "check_id": "credential_read",
    "failing": 293
   },
   {
    "kind": "skill",
    "check_id": "description",
    "failing": 1093
   },
   {
    "kind": "skill",
    "check_id": "exfil_hosts",
    "failing": 21
   },
   {
    "kind": "skill",
    "check_id": "frontmatter",
    "failing": 794
   },
   {
    "kind": "skill",
    "check_id": "hidden_comment",
    "failing": 7
   },
   {
    "kind": "skill",
    "check_id": "hidden_style",
    "failing": 27
   },
   {
    "kind": "skill",
    "check_id": "injection",
    "failing": 236
   },
   {
    "kind": "skill",
    "check_id": "name",
    "failing": 1263
   },
   {
    "kind": "skill",
    "check_id": "pipe_to_shell",
    "failing": 395
   },
   {
    "kind": "skill",
    "check_id": "raw_ip",
    "failing": 611
   },
   {
    "kind": "skill",
    "check_id": "rm_rf",
    "failing": 54
   },
   {
    "kind": "skill",
    "check_id": "script_tag",
    "failing": 718
   },
   {
    "kind": "skill",
    "check_id": "secret_shapes",
    "failing": 18
   },
   {
    "kind": "skill",
    "check_id": "size",
    "failing": 797
   },
   {
    "kind": "skill",
    "check_id": "zero_width",
    "failing": 77
   }
  ],
  "audit_versions": [
   {
    "v": 3,
    "n": 43512
   },
   {
    "v": 4,
    "n": 25607
   }
  ],
  "vendored": [
   {
    "name": "skill-creator",
    "up_id": "art_hl7wjhua3foziup4",
    "up_versions": 4,
    "copies": 101,
    "current": 14,
    "older": 8,
    "other": 79
   },
   {
    "name": "frontend-design",
    "up_id": "art_gvi6xzc6elndc3u6",
    "up_versions": 4,
    "copies": 72,
    "current": 3,
    "older": 12,
    "other": 57
   },
   {
    "name": "docx",
    "up_id": "art_qhvq2lp3auskkm76",
    "up_versions": 4,
    "copies": 33,
    "current": 3,
    "older": 10,
    "other": 20
   },
   {
    "name": "pptx",
    "up_id": "art_ravt22x6wnra75eg",
    "up_versions": 3,
    "copies": 31,
    "current": 3,
    "older": 8,
    "other": 20
   },
   {
    "name": "xlsx",
    "up_id": "art_pze7rppj2yulxgcf",
    "up_versions": 3,
    "copies": 29,
    "current": 5,
    "older": 9,
    "other": 15
   }
  ],
  "most_copied": [
   {
    "name": "AGENTS.md@apps/web",
    "kind": "agents",
    "repos": 15,
    "copies": 18,
    "first_id": "art_koy4dtwnpppvrxze",
    "size": 678
   },
   {
    "name": "skill-creator",
    "kind": "skill",
    "repos": 15,
    "copies": 15,
    "first_id": "art_hl7wjhua3foziup4",
    "size": 33168
   },
   {
    "name": "doc-coauthoring",
    "kind": "skill",
    "repos": 12,
    "copies": 12,
    "first_id": "art_ktioqgl7lkbjwml6",
    "size": 15815
   },
   {
    "name": "AGENTS.md@benchmarks/runs/superpowers",
    "kind": "agents",
    "repos": 10,
    "copies": 13,
    "first_id": "art_ebsvm5xsblpffdv6",
    "size": 327
   },
   {
    "name": "internal-comms",
    "kind": "skill",
    "repos": 10,
    "copies": 10,
    "first_id": "art_4qfdtiofuohngwta",
    "size": 1511
   },
   {
    "name": "theme-factory",
    "kind": "skill",
    "repos": 10,
    "copies": 10,
    "first_id": "art_igshavlzca2r3thz",
    "size": 3124
   },
   {
    "name": "codebase-design",
    "kind": "skill",
    "repos": 9,
    "copies": 10,
    "first_id": "art_wb5dphfswr2hjeq4",
    "size": 6446
   },
   {
    "name": "brand-guidelines",
    "kind": "skill",
    "repos": 9,
    "copies": 9,
    "first_id": "art_7i7vbtfp5hcho2rf",
    "size": 2235
   },
   {
    "name": "pdf",
    "kind": "skill",
    "repos": 9,
    "copies": 9,
    "first_id": "art_ce4b5ce6jbirfqqt",
    "size": 8072
   },
   {
    "name": "algorithmic-art",
    "kind": "skill",
    "repos": 9,
    "copies": 9,
    "first_id": "art_jzfkreew2atmppwl",
    "size": 19769
   }
  ]
 }
}