VY

vyper-compiler

Internal development guide for the Vyper compiler codebase.

Install

mkdir -p .claude/skills/vyper-compiler && curl -L -o skill.zip "https://agentskills.codes/api/skills/download/18028" && unzip -o skill.zip -d .claude/skills/vyper-compiler && rm skill.zip

Installs to .claude/skills/vyper-compiler

Activation

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Vyper smart contract compiler internals. Use when working on the Vyper compiler codebase — compilation pipeline, Venom IR, semantic analysis, code generation, testing, or contributing. Triggers on vyper compiler development, Venom passes, AST/semantics changes, codegen work, or test writing.
292 chars✓ has a “when” triggerlonger than Claude Code's old 250-char listing cap (fine on current versions)
Advanced

Key capabilities

  • Compile Vyper smart contracts
  • Inspect Venom IR output
  • Inspect assembly output
  • Run compiler tests
  • Enforce code style with linting
  • Parse Vyper source to AST

How it works

The skill uses `uv run` to execute Vyper compiler commands within a local virtual environment, orchestrating compilation phases like parsing, semantic analysis, and code generation.

Inputs & outputs

You give it
Vyper contract file (.vy)
You get back
Compiled bytecode, Venom IR, or assembly

When to use vyper-compiler

  • Compile vyper contract
  • Inspect Venom IR output
  • Run compiler tests

About this skill

Vyper Compiler

Pythonic smart contract language targeting the EVM. v0.4.x, Python 3.11+.

Quick Commands

uv sync                                 # install deps (per-worktree .venv, recommended, includes dev group)
uv run vyper contract.vy                # compile a contract
uv run vyper -f ir_runtime contract.vy  # inspect Venom IR
uv run vyper -f asm contract.vy         # inspect assembly
uv run ./quicktest.sh                   # run tests (`-nauto -m "not fuzzing"` by default via setup.cfg)
uv run make lint                        # enforces code style (same as CI)

Prefix all commands with uv run — it activates the local .venv per invocation, which is necessary in non-interactive shells. Each worktree gets its own .venv, so no cross-contamination.

Alternative: pip install . --group dev + PYTHONPATH=. prefix on every command. Never pip install -e . — it creates an egg-link in site-packages that permanently points the venv at one worktree, breaking all others.

Compilation Pipeline

Source (.vy)
  │
  ├─ vyper/ast/            → Parse to AST (pre_parser → Python AST → Vyper AST)
  ├─ vyper/semantics/      → Type check, validate, annotate AST
  ├─ vyper/codegen/        → AST → s-expr IR (default production pipeline)
  ├─ vyper/ir/             → s-expr IR → assembly → bytecode
  └─ vyper/evm/            → Assembly → bytecode

Experimental Venom path (--experimental-codegen):

  ├─ vyper/codegen_venom/  → AST → Venom SSA IR
  └─ vyper/venom/          → Venom IR optimization passes → assembly

Orchestrated by vyper/compiler/phases.py (CompilerData). Each phase is lazy.

Directory Map

DirectoryPurpose
vyper/ast/Parsing, AST nodes, pre-parser. See AST README
vyper/semantics/Type system, analysis, validation. See Semantics README
vyper/codegen/AST → s-expr IR (default production pipeline)
vyper/ir/s-expr IR → assembly → bytecode. See IR README
vyper/codegen_venom/AST → Venom IR (experimental, --experimental-codegen)
vyper/venom/Venom SSA IR: passes, analysis, assembly emission. See Venom README
vyper/compiler/Pipeline orchestration, settings, output formats. See Compiler README
vyper/builtins/Built-in functions and interfaces
vyper/evm/EVM opcodes, assembler
vyper/cli/CLI entry points (vyper, vyper-ir, venom)
tests/unit/Unit tests (ast, semantics, compiler, venom)
tests/functional/Functional tests (builtins, codegen, grammar, syntax, venom)

Topic Deep-Dives

  • Venom IR — SSA IR design, passes, optimization, working with Venom code
  • Semantics & Frontend — Type system, analysis phases, namespace, validation
  • Code Generation — Legacy IR, Venom codegen, the two pipelines
  • Testing — Test structure, fixtures, running tests, writing new tests
  • Contributing — Commit message standards, PR workflow, code style summary

Code Style

Enforced by make lint (also what CI runs). Includes black, flake8, isort, mypy.

  • Line length: 100
  • No inline imports; standard library → third-party → local
  • snake_case for variables (tmp = ...), DromedaryCase (aka upper camelCase) for classes (ExprAnalyzer), type classes end in T (e.g. IntegerT, ModuleT)

Key Entry Points

WhatWhere
Main compile functionvyper.compiler.compile_code()
Pipeline phasesvyper.compiler.phases.CompilerData
AST parsingvyper.ast.parse.parse_to_ast()
Semantic analysisvyper.semantics.analyze_module()
Legacy codegenvyper.codegen.module
AST → Venom IRvyper.codegen_venom.module
Venom → assemblyvyper.venom.generate_assembly_experimental()
CLI entryvyper.cli.vyper_compile

When not to use it

  • When not working on the Vyper compiler codebase
  • When not developing Vyper compiler features
  • When not contributing to the Vyper compiler

Limitations

  • Requires a local `.venv` activated via `uv run`
  • Specific to Vyper compiler development tasks
  • Python 3.11+ is required

How it compares

This workflow provides direct access to compiler internals and intermediate representations, unlike standard contract compilation.

Compared to similar skills

vyper-compiler side by side with the closest alternatives in the catalog.

SkillInstallsUpdatedSafetyDifficulty
vyper-compiler (this skill)02moReviewAdvanced
temporal-python-testing83moNo flagsAdvanced
python-pro233moNo flagsAdvanced
home-assistant-integration-knowledge82moNo flagsAdvanced

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