H4: Context Boundary Erosion #

The instruction asks for unscoped context retention or leaves a detectable context boundary unclear.

H4MEDIUM–HIGHLintLang 0.8.0

Applies to: Recognized prompts, instructions, message sequences, and eligible disk references. Manual repair; no automatic fix for this example.

What triggers it #

Checks selected remember-everything/context language and qualified long-prompt boundary cases. Long message sequences can also lack recognized task boundaries. H4.5 is the specific missing-file diagnostic.

How to repair it #

Name what should persist and for how long. Check referenced instruction paths when files move.

Reproduce the finding #

Use uv and Python 3.10+, plus curl. Run the examples in a scratch directory.

Download the finding example.

{
  "system_prompt": "Remember everything from every conversation."
}

curl -fsS https://lintlang.ai/examples/rules/h4-bad.json -o h4-bad.json
uvx --from lintlang==0.8.0 lintlang scan h4-bad.json --format json

Expected with 0.8.0: the JSON report includes H4, severity HIGH.

Improved example #

Download the improved example.

{
  "system_prompt": "Retain the invoice ID for this task only. Start each new task with an empty invoice selection."
}

curl -fsS https://lintlang.ai/examples/rules/h4-improved.json -o h4-improved.json
uvx --from lintlang==0.8.0 lintlang scan h4-improved.json --format json

Expected with 0.8.0: H4 is absent. Other diagnostics may still appear; this repair targets the rule above.

Both commands use advisory mode: a finding does not itself make the command fail. To fail CI on HIGH or CRITICAL findings, add --fail-on fail. --fail-on review also gates MEDIUM. See outputs and exit codes.

Detection details #

Released H4 detection contract and scope

Checks selected unscoped requests to remember everything or use all conversation, history, or context; unbounded always-remember language; and, for chat prompts only, long prompts without recognized boundary markers. It does not inspect a host's actual context window.

H4.5 (MEDIUM; only AGENTS.md, CLAUDE.md, GEMINI.md, SKILL.md, Copilot instruction files and files with skill front matter, read from disk) reports a referenced project file that does not exist. It needs all of: a literal relative path with a directory part and a known file extension, in backticks or a Markdown link, outside fenced code; a first segment that exists beside the document or at the repository root; a path that resolves from neither; and a line that does not talk about creating, renaming, removing or exemplifying it. It reads the filesystem, so it does not run on standard input, and it is deliberately quiet: directories, globs, placeholders and paths into other projects are never reported.

All scan rules · Quickstart · Separate preflight checks.