A linter for agent instructions

Make your agents mean it.

LintLang flags vague tool descriptions, missing operational limits, mixed output-format instructions, vague qualifiers, and context-boundary risks before runtime review.

Free and open source · Built by Hermes Labs

agent-config.md

lintlang

Illustrative rendering of an exercised LintLang 0.4.1 scan

1Keep trying until it works.
!
CRITICAL · H2 Missing Constraint Scaffolding Unbounded retry loop needs an explicit limit.
2Respond in JSON and Markdown.
!
MEDIUM · H6 Template Format Contract Violation References multiple output formats and may produce hybrid output.
Clear instructionsBetter reviewFewer surprisesClear instructionsBetter reviewFewer surprises

Natural language is a beautiful interface. It is also a very loose one.

Agent configurations are becoming application code, but they are still written and reviewed like prose. LintLang gives your instructions the same disciplined feedback loop as the rest of your stack.

Explore the approach
01

Flag mixed output-format instructions

Surface references to multiple output formats that may lead to hybrid output.

02

Expose bounded risks

Spot vague tool descriptions and qualifiers, missing operational limits, and context-boundary risks.

03

Set a baseline

Bring repeatable checks to every change, from a local prompt edit to a CI pull request.

Write. Check. Ship with intent.

  1. 1

    Point at supported instructions

    Scan recognized JSON/YAML agent-config shapes, .txt, .md, and .prompt files, or Python files with extractable prompts.

  2. 2

    Read findings in context

    Each finding reports a detected pattern, severity, logical location, and suggested review action. Findings may remain at file or logical-location level.

  3. 3

    Keep the standard in CI

    Turn configuration review from a heroic habit into a dependable part of your delivery flow.

Put a check between the draft and the deploy.

Install it locally, run it against the instruction file in front of you, then bring the same command into CI.

Working with a coding agent? Tell it: “Install LintLang and run it against our agent instructions before changing them.”

Install LintLang · Python 3.10+

$ python -m pip install lintlang

View the package on PyPI

Language is part of the runtime.

LintLang brings static analysis to the language agents execute: before runtime review and evaluation.

01 / IN CI

Character.AI

Added to its Larch consolidated third-party CI lint job: 236 files passed with no HIGH or CRITICAL findings.

Read the merged PR ↗
02 / DISTRIBUTION

8,508 downloads

All-time PyPI downloads including mirrors; 4,269 downloads excluding known mirrors. Coverage through August 21, 2026.

Inspect the PyPI stats ↗
03 / PACKAGING

Gentoo-ready

Packaged in the community-maintained Haven overlay for Gentoo, with ebuilds through version 0.4.1.

Browse the ebuilds ↗
04 / OPEN SOURCE

Built in public

An Apache-2.0 package with public source, designed to fit a local-first engineering workflow.

Explore the repository ↗
Evidence, not endorsements:Public receipts checked August 22, 2026; PyPI all-time counts cover through August 21.

Built for the messy parts of language.

LintLang is designed around a simple idea: instructions deserve clear, actionable feedback without pretending that language is perfectly deterministic.

Read the docs
01

Human-readable findings

Feedback for the people who write and maintain agent behavior.

02

Severity with judgment

Focus attention where an instruction failure can carry real consequences.

03

Local-first workflow

Check the configuration in front of you, then bring it into your pipeline.

Give your agents a clearer set of instructions.

Install LintLang