zig-async-io

zig-async-io is a skill for Claude Code from whit3rabbit/claude-zig-skill. It costs 72 tokens per session (2,006 once invoked), scanned A, original, MIT.

A guide to asynchronous input and output in Zig 0.16.0 using the new std.Io interface. Asynchronous I/O lets programs handle waiting operations without stopping all other work; Zig is a systems programming language.

In plain words
What is it for?
Use it when building non-blocking I/O, event loops, futures, cancellation, concurrent tasks, or different I/O execution models in Zig 0.16.0 and later.
Why use it?
It explains the new Zig 0.16.0 approach and helps avoid confusing asynchronous work with simultaneous parallel work.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the zig-async plugin — 1 skill shipped together

Good fit Use it when building non-blocking I/O, event loops, futures, cancellation, concurrent tasks, or different I/O execution models in Zig 0.16.0 and later.

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Install with agentmods
npx agentmods add skills/whit3rabbit/claude-zig-skill/zig-async-skill
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.

Any agent
npx skills add whit3rabbit/claude-zig-skill --skill zig-async-skill
Clone the repo
git clone --depth 1 https://github.com/whit3rabbit/claude-zig-skill

Made for: Claude Code.

Or install zig-async, the plugin that ships this one along with the rest of its 1 skill.

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 zig-async-io

README.md
[![agentmods](https://agentmods.dev/badge/skills/whit3rabbit/claude-zig-skill/zig-async-skill.svg)](https://agentmods.dev/skills/whit3rabbit/claude-zig-skill/zig-async-skill)
Your own site
<a href="https://agentmods.dev/skills/whit3rabbit/claude-zig-skill/zig-async-skill"><img src="https://agentmods.dev/badge/skills/whit3rabbit/claude-zig-skill/zig-async-skill.svg" alt="Measured on agentmods" height="20"></a>
Per session 72 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,006 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00072 $0.02006
Opus 5 $0.00036 $0.01003
Sonnet 5 $0.00014 $0.00401
Haiku 4.5 $0.00007 $0.00201

Measured 8d ago against content hash f924d70a18d7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

zig-async-io 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 8d 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.

zig-async-skill/SKILL.md · 258 lines

How it starts

The opening of the file, as written. The whole thing — 258 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Zig Async I/O Skill (0.16.0+)

Overview

Zig 0.16.0 introduces a redesigned async I/O system based on the std.Io interface. Unlike the old async/await (removed in 0.11), the new design decouples concurrency expression from execution models, allowing code to work optimally across synchronous, multi-threaded, and event-driven contexts.

Critical Concept: Asynchrony ≠ Concurrency

  • async: Operations can proceed out-of-order (sequential awaiting is valid)
  • concurrent: Operations must proceed simultaneously (requires parallelism)

Table of Contents

Bundled Resources

References

Fundamentals:

  • references/async-overview.md - New async I/O design philosophy
  • references/io-interface.md - std.Io interface and primitives
  • references/async-vs-concurrent.md - Critical distinction explained

Patterns:

  • references/future-handling.md - Future.await() and Future.cancel()
  • references/resource-management.md - Defer patterns for async resources
  • references/io-implementations.md - Blocking, ThreadPool, EventLoop, Stackless

Advanced:

  • references/message-passing.md - Io.Queue for synchronization
  • references/vectorized-io.md - sendFile() and drain() operations
  • references/migration-guide.md - From old async or sync code

Examples

Complete async I/O demonstrations:

  • examples/basic_async.zig - Simple async operations with io.async()
  • examples/concurrent_tasks.zig - True concurrency with io.concurrent()
  • examples/file_operations.zig - Async file I/O patterns
  • examples/http_server.zig - Async HTTP server with event loop
  • examples/producer_consumer.zig - Message passing with Io.Queue
  • examples/cancellation.zig - Proper task cancellation patterns

Templates

Starting points for async code:

  • assets/templates/async-function.zig - Async function template
  • assets/templates/async-server.zig - Async server template
  • assets/templates/async-client.zig - Async client template
  • assets/templates/threaded-io.zig - Thread pool I/O setup

Read the full file on GitHub · 258 lines

Files

What ships with it

8 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. 8d ago First seen · 258 lines · 72 tokens per session scan A f924d70a18d7

Subscribe to this mod's changes

zig-async-io is a skill published in the GitHub repository whit3rabbit/claude-zig-skill (23 stars, last pushed 8mo ago), licensed MIT. It adds 72 tokens to every session and 2,006 once invoked, about $0.0004 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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