ty

ty is a skill for Claude Code, Codex from hyperb1iss/hyperskills. It costs 69 tokens per session (2,230 once invoked), scanned A, original, MIT.

A Python type checker and language server named ty. Type checking finds likely mistakes in how values and functions are used, while a language server provides related editor assistance.

In plain words
What is it for?
Use it to check Python projects, configure type checking in pyproject.toml or ty.toml, and set up editor support. It is relevant when replacing or comparing tools such as mypy or Pyright.
Why use it?
It catches type errors without running the program and can provide fast feedback in large projects. The guide also notes its early beta status and limits around plugins used by some Python frameworks.

Skill for Claude CodeCodex

Part of the hyperskills plugin — 18 skills shipped together

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/hyperb1iss/hyperskills/ty
Any agent
npx skills add hyperb1iss/hyperskills --skill ty
Clone the repo
git clone --depth 1 https://github.com/hyperb1iss/hyperskills

Made for: Claude Code, Codex.

Or install hyperskills, the plugin that ships this one along with the rest of its 18 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ty

README.md
[![agentmods](https://agentmods.dev/badge/skills/hyperb1iss/hyperskills/ty.svg)](https://agentmods.dev/skills/hyperb1iss/hyperskills/ty)
Your own site
<a href="https://agentmods.dev/skills/hyperb1iss/hyperskills/ty"><img src="https://agentmods.dev/badge/skills/hyperb1iss/hyperskills/ty.svg" alt="Measured on agentmods" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,230 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00069 $0.02230
Opus 5 $0.00034 $0.01115
Sonnet 5 $0.00014 $0.00446
Haiku 4.5 $0.00007 $0.00223

Measured 4d ago against content hash e1fce5c01d0a, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ty scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/ty/SKILL.md · 255 lines

How it starts

The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.

ty: Python Type Checker & Language Server

ty is Astral's Rust-based Python type checker and language server. Beta status: 0.0.x versioning, breaking changes between versions, and no stable API yet. Astral reports 10-100x faster checks than mypy and Pyright on large projects.

Snapshot: v0.0.34, May 2026. The installed binary outranks this file, and it rots faster here than in the other Astral skills: 0.0.x means flags, rule names, and config keys move between releases. Check ty --version and ty check --help before trusting a flag, and ty explain rule for current rule names.

Formerly "Red-Knot", renamed May 2025, extracted from the ruff repo to astral-sh/ty.

When to Use ty

  • [tool.ty] section in pyproject.toml or ty.toml exists
  • Type checking Python code in any project
  • Setting up an LSP for Python in your editor

When to wait: Projects heavily dependent on mypy plugins (Pydantic, Django, SQLAlchemy). ty has no plugin system and no plans to add one, first-class framework support is the stated approach instead.

How to Invoke

uvx ty check                  # One-off (latest)
uv run ty check               # Project dependency
ty check                      # Global install

CLI Commands

# Type checking
ty check                           # Check current directory
ty check path/to/file.py           # Specific file
ty check src/ tests/               # Multiple directories

# Rule severity
ty check --error unresolved-import
ty check --warn division-by-zero
ty check --ignore unresolved-attribute

# Python targeting
ty check --python-version 3.12
ty check --python-platform linux
ty check --python .venv/bin/python

# Output formats
ty check --output-format full      # Rich diagnostics (default)
ty check --output-format concise   # One line per error
ty check --output-format github    # GitHub Actions annotations
ty check --output-format gitlab    # GitLab Code Quality
ty check --output-format junit     # JUnit XML

# Watch mode
ty check --watch                   # Re-check on file changes
ty check -W                        # Short form

# Migration helper
ty check --add-ignore              # Auto-add ty: ignore comments for all errors

# Introspection
ty explain rule                    # List all rules
ty explain rule invalid-assignment # Explain specific rule

# Language server
ty server                          # Start LSP

Read the full file on GitHub · 255 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 255 lines · 69 tokens per session scan A e1fce5c01d0a

Subscribe to this mod's changes

ty is a skill published in the GitHub repository hyperb1iss/hyperskills (31 stars, last pushed 8d ago), licensed MIT. It adds 69 tokens to every session and 2,230 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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