parallelism

parallelism is a skill for Claude Code, Codex from onsi/ginkgo. It costs 108 tokens per session (1,558 once invoked), scanned A, original, MIT.

A guide to running Ginkgo tests in parallel across separate operating-system processes. Ginkgo is a Go testing framework, and its command-line tool coordinates which tests each process runs.

In plain words
What is it for?
Use it to configure parallel test processes, split resources by process, run shared setup and cleanup correctly, and capture output from child programs.
Why use it?
It helps shorten test runs while exposing tests that incorrectly share ports, temporary folders, databases, or other state.

Skill for Claude CodeCodex

Part of the ginkgo plugin — 13 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/onsi/ginkgo/parallelism
Any agent
npx skills add onsi/ginkgo --skill parallelism
Clone the repo
git clone --depth 1 https://github.com/onsi/ginkgo

Made for: Claude Code, Codex.

Or install ginkgo, the plugin that ships this one along with the rest of its 13 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 parallelism

README.md
[![agentmods](https://agentmods.dev/badge/skills/onsi/ginkgo/parallelism.svg)](https://agentmods.dev/skills/onsi/ginkgo/parallelism)
Your own site
<a href="https://agentmods.dev/skills/onsi/ginkgo/parallelism"><img src="https://agentmods.dev/badge/skills/onsi/ginkgo/parallelism.svg" alt="Measured on agentmods" height="20"></a>
Per session 108 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,558 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 $0.00108 $0.01558
Opus 5 $0.00054 $0.00779
Sonnet 5 $0.00022 $0.00312
Haiku 4.5 $0.00011 $0.00156

Measured 3d ago against content hash 0d939a9f7e52, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

parallelism 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 3d 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.

plugins/ginkgo/skills/parallelism/SKILL.md · 96 lines

How it starts

The opening of the file, as written. The whole thing — 96 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Running Ginkgo in parallel

Parallelism is where Ginkgo's "every spec is independent" assumption (ginkgo:overview) earns its keep. If your specs are independent, going parallel is one flag. If they aren't, parallelism is how you find out. Docs: https://onsi.github.io/ginkgo/#spec-parallelization, https://onsi.github.io/ginkgo/#patterns-for-parallel-integration-specs.

The flag

ginkgo -p            # auto-detect optimal process count from CPU cores
ginkgo --procs=4     # pin the count explicitly
ginkgo watch -p      # re-run in parallel on every file change

-p/--procs require the ginkgo CLI — go test cannot parallelize a Ginkgo suite (it has no server to coordinate processes). Most other features work under go test; parallelism is the headline exception. → ginkgo:running.

The mental model: separate processes, not goroutines

This is the one thing to internalize. Ginkgo compiles the suite once (go test -c), then launches N copies of the test binary as separate OS processes. Each process runs the full tree-construction phase independently (so all N build the identical spec list), then pulls specs to run from the CLI, which acts as a server and merges everything into one coherent output stream.

  • Separate processes means separate memory. Each process has its own copy of every package-level var and closure variable. There is no shared memory, so shared-closure specs like var book don't race across processes — they each get their own book. (Within a process specs still run one at a time.)
  • The flip side: a BeforeSuite runs on every process, so anything it creates is created N times.
  • You usually don't care which process runs a spec — except for the integration patterns below, which deliberately shard shared external resources by process index.

Suite setup when N copies is wrong: Synchronized*Suite

BeforeSuite runs on every process → N independent resources. Sometimes that's ideal (max isolation). When a resource is expensive or must be shared, use SynchronizedBeforeSuite: set it up once on process #1, then distribute connection info to all processes.

Read the full file on GitHub · 96 lines

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. 3d ago First seen · 96 lines · 108 tokens per session scan A 0d939a9f7e52

Subscribe to this mod's changes

parallelism is a skill published in the GitHub repository onsi/ginkgo (9,046 stars, last pushed 23d ago), licensed MIT. It adds 108 tokens to every session and 1,558 once invoked, about $0.0005 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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