State of agent context, October 2026
We graded the agent instructions of 210 public GitHub repositories with threadctx. Aggregates only; no repository is named.
of the 184 repositories with instruction files keep them in the formats of two or more tools (AGENTS.md counts as one).
keep two or more tool-specific formats (Claude, Cursor, Copilot, Gemini).
score an A. Most repositories are in good shape; the problems cluster.
median scan time per repository.
How common is each problem?
Share of the 184 repositories with instruction files that trigger each rule, with the rule’s measured false-positive rate. Beta rules are directional.
| Rule | Problem | Repos | Share | FP rate |
|---|---|---|---|---|
CTX-S002 | Two or more tool-specific context files with no shared source | 43 | 23% | 0.0% FP (n=43, ≤8.2%) |
CTX-B004 | Same directive repeated across files | 30 | 16% | 0.0% FP (n=70, ≤5.2%) |
CTX-B001 | Always-loaded context exceeds the token budget for a tool | 28 | 15% | 0/29 · not yet established |
CTX-S006 | Deprecated context format in use | 28 | 15% | 0/28 · not yet established |
CTX-S001 | No agent context file in repository | 26 | 14% | 0/26 · not yet established |
CTX-D001 | Referenced path does not exist | 25 | 14% | 12% FP (n=60, ≤22%) · beta |
CTX-X006 | MCP server not pinned to a version | 11 | 6% | 0/22 · not yet established |
CTX-D002 | Referenced command or script is not defined | 5 | 3% | 0/14 · not yet established |
CTX-D005 | Stated major version contradicts installed version | 5 | 3% | 0/6 · not yet established |
CTX-G001 | Context files not covered by CODEOWNERS | 5 | 3% | 0/5 · not yet established |
CTX-S003 | Broken import or reference to a missing context file | 5 | 3% | 0/11 · not yet established |
CTX-B003 | Generic boilerplate with no repository-specific content | 3 | 2% | 0/5 · not yet established · beta |
CTX-S004 | Rule glob or path scope matches no files | 3 | 2% | 0/11 · not yet established |
CTX-C002 | AGENTS.md and CLAUDE.md shared sections have diverged | 2 | 1% | 0/3 · not yet established · beta |
CTX-D004 | Referenced dependency absent from manifests | 2 | 1% | 6/17 · not yet established · beta |
CTX-B002 | Section duplicates README or docs content | 1 | 1% | 0/2 · not yet established · beta |
CTX-S005 | Invalid frontmatter in a rule or instruction file | 1 | 1% | 0/1 · not yet established · beta |
What we did not find
No confirmed contradictory package managers or test runners between files; no bidirectional or Unicode-tag characters; no instructions to bypass checks or hide changes; no committed credentials in context files. A few repositories use curl-pipe-to-shell installers from well-known vendors, which threadctx allow-lists, and some contain stray zero-width spaces from copy-paste, which it does not flag. The common problems are quieter: stale paths, copies that never see the shared file, duplicated text, and context that grows past what is worth loading every session.
Method and limits
- Selected with GitHub code search on 7 file-name queries (AGENTS.md, CLAUDE.md, .cursorrules, .cursor/rules, Copilot instructions, GEMINI.md, .mcp.json), repositories with at least 20 stars, not forks or archived, pinned to a commit.
- The corpus is biased toward repositories that already have context files. It says nothing about how many repositories lack them.
- Every finding was reviewed by hand. See methodology.
- Rules measured at or over 5% false positives are shown but reported at info and stay beta.