Agent skill

Gexec

Testing external processes with gexec — compile binaries with Build/BuildWithEnvironment/BuildIn and CleanupBuildArtifacts, start them with Start returning a Session, await exit with the Exit…

MITAuto-check passedDevelopment

Install Gexec

skills CLI

$ npx skills add onsi/gomega --skill gexec -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI

$ gh skill install onsi/gomega gexec --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy

$ git clone --depth 1 https://github.com/onsi/gomega.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/gomega/skills/gexec .claude/skills/gexec && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Paste into Claude Code

Install the "gexec" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec into .claude/skills/gexec/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gexec", then confirm the skill loads.

Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

$skill-installer

$skill-installer install https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec

Type this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.

skills CLI

$ npx skills add onsi/gomega --skill gexec -a codex

Project install goes to .agents/skills/; add -g for ~/.codex/skills/.

GitHub CLI

$ gh skill install onsi/gomega gexec --agent codex

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/onsi/gomega.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/gomega/skills/gexec .agents/skills/gexec && rm -rf skills-src

Use ~/.agents/skills/ instead of .agents/skills for a personal install.

Codex skills documentation · loads skills from .agents/skills/

Paste into Codex

Install the "gexec" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec into .agents/skills/gexec/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gexec", then confirm the skill loads.

Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add onsi/gomega --skill gexec -a cursor

Project install goes to .agents/skills/; add -g for ~/.cursor/skills/.

GitHub CLI

$ gh skill install onsi/gomega gexec --agent cursor

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/onsi/gomega.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/gomega/skills/gexec .cursor/skills/gexec && rm -rf skills-src

Use ~/.cursor/skills/ instead of .cursor/skills for a personal install.

Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/

Paste into Cursor

Install the "gexec" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec into .cursor/skills/gexec/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gexec", then confirm the skill loads.

Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

gemini skills install

$ gemini skills install https://github.com/onsi/gomega.git --path plugins/gomega/skills/gexec

--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.

skills CLI

$ npx skills add onsi/gomega --skill gexec -a gemini-cli

Project install goes to .agents/skills/; add -g for ~/.gemini/skills/.

GitHub CLI

$ gh skill install onsi/gomega gexec --agent gemini-cli

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/onsi/gomega.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/gomega/skills/gexec .gemini/skills/gexec && rm -rf skills-src

Use ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.

Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/

Paste into Gemini CLI

Install the "gexec" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec into .gemini/skills/gexec/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gexec", then confirm the skill loads.

Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

GitHub CLI

$ gh skill install onsi/gomega gexec

Installs for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).

skills CLI

$ npx skills add onsi/gomega --skill gexec -a github-copilot

Project install goes to .agents/skills/; add -g for ~/.copilot/skills/.

Manual copy

$ git clone --depth 1 https://github.com/onsi/gomega.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/gomega/skills/gexec .github/skills/gexec && rm -rf skills-src

Use ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.

GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/

Paste into GitHub Copilot

Install the "gexec" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec into .github/skills/gexec/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gexec", then confirm the skill loads.

GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

skills CLI

$ npx skills add onsi/gomega --skill gexec -a opencode

OpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.

GitHub CLI

$ gh skill install onsi/gomega gexec --agent opencode

Project scope by default (.agents/skills/); add --scope user for a personal install.

Manual copy

$ git clone --depth 1 https://github.com/onsi/gomega.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/gomega/skills/gexec .opencode/skills/gexec && rm -rf skills-src

Use ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.

OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/

Paste into OpenCode

Install the "gexec" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gexec into .opencode/skills/gexec/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gexec", then confirm the skill loads.

OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.

Facts

Skill name: gexec
GitHub stars: 2.4k
Token cost: ~1.3k tokens
SKILL.md length: 332 words
Files: 1
Skills in repo: 12
Repo updated: Sep 24, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Testing external processes with gexec — compile binaries with Build/BuildWithEnvironment/BuildIn and CleanupBuildArtifacts, start them with Start returning a Session, await exit with the Exit…

Asserting on subprocesses in Go tests
SKILL.md covers Compiling binaries, Starting a process, Asserting on exit and Sending signals, plus 2 more sections
Calls go

What it does

Gexec is an agent skill from onsi/gomega. Testing external processes with gexec — compile binaries with Build/BuildWithEnvironment/BuildIn and CleanupBuildArtifacts, start them with Start returning a Session, await exit with the Exit matcher (Eventually(session).Should(Exit(0))), Wait/ExitCode, signal via Kill/Terminate/Interrupt/Signal and package-level KillAndWait/TerminateAndWait, and assert on session.Out/Err which are gbytes buffers (Say, Contents). Use when building, running, signaling, or asserting on subprocesses in Go tests.

Its SKILL.md is about 1.3k tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Development. The repository describes itself as: Ginkgo's Preferred Matcher Library. The licence is MIT.

When your agent uses it

Asserting on subprocesses in Go tests

Example prompts

“/gexec”

What it can do on your machine

Read from SKILL.md and the folder at commit 37fa900. It shows what the files ask for, not the result of running them.

Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
- go
From the folder's file list and the shell code blocks in SKILL.md.
Network
Links to these hosts (documentation or services it may open):
- onsi.github.io
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Gexec loads about 1.3k tokens when it runs. Until then it costs about 126 tokens; SKILL.md has 332 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~126
When it runs · the whole SKILL.md, loaded when a task matches: ~1.3k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from onsi/gomega at commit 37fa900, republished under its MIT licence (© onsi). 332 words, ~1,318 tokens.

Download SKILL.mdSave it as .claude/skills/gexec/SKILL.md (or your agent's skills folder).

name: gexec
description: Testing external processes with gexec — compile binaries with Build/BuildWithEnvironment/BuildIn and CleanupBuildArtifacts, start them with Start returning a *Session, await exit with the Exit matcher (Eventually(session).Should(Exit(0))), Wait/ExitCode, signal via Kill/Terminate/Interrupt/Signal and package-level KillAndWait/TerminateAndWait, and assert on session.Out/Err which are gbytes buffers (Say, Contents). Use when building, running, signaling, or asserting on subprocesses in Go tests.

gexec: testing external processes

gexec compiles Go binaries, starts them as subprocesses, sends them signals, and exposes their stdout/stderr as gbytes.Buffers so you can assert on streaming output and exit codes. Import it normally (Gomega is dot-imported):

import (
	. "github.com/onsi/gomega"
	. "github.com/onsi/ginkgo/v2"
	"github.com/onsi/gomega/gexec"
)

Docs: https://onsi.github.io/gomega/#gexec-testing-external-processes.

Compiling binaries

gexec.Build(packagePath, ...args) runs go build and returns the path to a temp binary.

var pathToCLI string

BeforeSuite(func() {
	var err error
	pathToCLI, err = gexec.Build("github.com/spacely/sprockets")
	Expect(err).NotTo(HaveOccurred())
})

AfterSuite(func() {
	gexec.CleanupBuildArtifacts()
})

gexec.BuildWithEnvironment(packagePath, env []string, ...args) — set env vars for the build (e.g. GOOS/GOARCH for cross-compilation).
gexec.BuildIn(gopath, packagePath, ...args) — build with a custom GOPATH (e.g. against vendored deps).

Always defer/AfterSuite gexec.CleanupBuildArtifacts(). It deletes the temp binaries; skipping it leaks files into your temp dir across runs.

Starting a process

gexec.Start(cmd, outWriter, errWriter) calls cmd.Start() and returns a *gexec.Session that wraps and monitors the process, forwarding stdout/stderr to the writers you pass.

command := exec.Command(pathToCLI, "-api=127.0.0.1:8899")
session, err := gexec.Start(command, GinkgoWriter, GinkgoWriter)
Expect(err).NotTo(HaveOccurred())

Pass GinkgoWriter for both writers. Output is then silent on passing tests but printed on failure (and always under ginkgo -v) — invaluable for debugging.

Asserting on exit

The gexec.Exit() matcher is pollable and only works on a *Session — pair it with Eventually (→ gomega:async):

Eventually(session).Should(gexec.Exit())   // exited, any code
Eventually(session).Should(gexec.Exit(0))  // exited with code 0

session.ExitCode() returns the raw code, or -1 if the process hasn't exited yet.

session.Wait([timeout]) blocks until exit (failing if it doesn't exit within the default Eventually timeout) and returns the session for chaining:

session.Wait(5 * time.Second)

Don't Wait on the wrapped exec.Cmd yourself — gexec already calls Wait to monitor the process. session.Wait is just Eventually under the hood.

Sending signals

session.Kill()         // SIGKILL
session.Interrupt()    // SIGINT
session.Terminate()    // SIGTERM
session.Signal(sig)    // arbitrary os.Signal

Each returns the session, so chain with Wait: session.Terminate().Wait(). Signaling an already-exited process is a no-op.

Signaling every started session

Package-level helpers signal all sessions gexec has started, in any context — ideal for cleanup:

gexec.Kill()              // SIGKILL to all
gexec.Terminate()         // SIGTERM to all
gexec.Interrupt()         // SIGINT to all
gexec.Signal(sig)         // os.Signal to all
gexec.KillAndWait()       // signal all, then wait
gexec.TerminateAndWait(2 * time.Second)  // per-process timeout

AfterSuite(func() { gexec.KillAndWait() })

These are global. Calling them in an AfterEach will also signal processes started in BeforeSuite. Good practice is to ensure all processes are killed before the suite ends.

Asserting on output

session.Out and session.Err are gbytes.Buffers connected to stdout/stderr, so use the gbytes.Say matcher for ordered streaming assertions (→ gomega:gbytes). The session itself is a BufferProvider for Out:

Eventually(session.Out).Should(gbytes.Say("hello [A-Za-z], nice to meet you"))
Eventually(session.Err).Should(gbytes.Say("oops!"))
Eventually(session).Should(gbytes.Say("hello"))  // shorthand for session.Out

To grab the whole output after exit, Wait() returns the session, so .Out.Contents() gives a []byte (→ gomega:matchers):

Expect(session.Wait().Out.Contents()).To(ContainSubstring("finished successfully"))

End-to-end

var pathToCLI string

var _ = BeforeSuite(func() {
	var err error
	pathToCLI, err = gexec.Build("github.com/spacely/sprockets")
	Expect(err).NotTo(HaveOccurred())
})

var _ = AfterSuite(func() {
	gexec.CleanupBuildArtifacts()
})

var _ = It("greets and exits cleanly", func() {
	command := exec.Command(pathToCLI, "--name=George")
	session, err := gexec.Start(command, GinkgoWriter, GinkgoWriter)
	Expect(err).NotTo(HaveOccurred())

	Eventually(session).Should(gbytes.Say("hello George"))
	Eventually(session).Should(gexec.Exit(0))
	Expect(session.Out.Contents()).To(ContainSubstring("done"))
})

Files

Just SKILL.md in plugins/gomega/skills/gexec of onsi/gomega.

Open the folder on GitHubat commit 37fa900

Compare with similar skills

Gexec next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Gexec compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Gexec this skillonsi/gomega	2.4k	—	~1.3k	Automated safety check: Pass	MIT	14 days ago
Vercel Composition Patternssupabase/supabase	111k	59 repos	~726	Automated safety check: Pass	MIT	today
Finishing a Development Branchobra/superpowers	296k	5 repos	~1.9k	Automated safety check: Pass	MIT	today
Typescript Advanced Typesrolling-scopes/rsschool-app	10k	25 repos	~4.2k	Automated safety check: Pass	MPL-2.0	4 days ago
PR Babysitteropeninterpreter/openinterpreter	69k	3 repos	~4.2k	Automated safety check: Pass	Apache-2.0	yesterday
Code Review ChecklistshareAI-lab/learn-claude-code	78k	5 repos	~1.1k	Automated safety check: Pass	MIT	10 days ago

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Questions about Gexec

What does Gexec do?

Testing external processes with gexec — compile binaries with Build/BuildWithEnvironment/BuildIn and CleanupBuildArtifacts, start them with Start returning a Session, await exit with the Exit…. Gexec is an agent skill from onsi/gomega.Out/Err which are gbytes buffers (Say, Contents).

When should I use Gexec?

Gexec fits situations like: asserting on subprocesses in Go tests.

How do I install Gexec in Claude Code?

Run `npx skills add onsi/gomega --skill gexec -a claude-code`. Or copy the skill folder (plugins/gomega/skills/gexec in onsi/gomega) into .claude/skills/gexec in your project. Claude Code loads it when a task matches its description.

How do I install Gexec in Codex?

Run `npx skills add onsi/gomega --skill gexec -a codex`. Or copy the skill folder (plugins/gomega/skills/gexec in onsi/gomega) into .agents/skills/gexec in your project. Codex loads it when a task matches its description.

Can I use Gexec in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add onsi/gomega --skill gexec -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/gexec, .gemini/skills/gexec, .github/skills/gexec and .opencode/skills/gexec in your project.

What does Gexec need to run?

Going by SKILL.md and its folder, Gexec needs the command-line tools its instructions call (go).

Does Gexec access the network?

SKILL.md names 1 domain. As links in the text: onsi.github.io. This is read from the text; nothing was executed.

Is Gexec safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Gexec use?

Gexec is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Gexec use?

About 1.3k tokens (SKILL.md is roughly 5.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Gexec?

Skills that share tags, products or a category with Gexec: Vercel Composition Patterns (supabase/supabase, 111k stars), Finishing a Development Branch (obra/superpowers, 296k stars), Typescript Advanced Types (rolling-scopes/rsschool-app, 10k stars) and PR Babysitter (openinterpreter/openinterpreter, 69k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Gexec?

onsi (a GitHub user) maintains it in onsi/gomega, which has 2,357 GitHub stars. The repository holds 12 skills in this directory. The repository was last updated on September 24, 2026.

Source: onsi/gomega on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.

Gexec

Install Gexec

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

gexec: testing external processes

Compiling binaries

Starting a process

Asserting on exit

Sending signals

Signaling every started session

Asserting on output

End-to-end

Files

Compare with similar skills

Similar skills

Vercel Composition Patterns

Finishing a Development Branch

Typescript Advanced Types

PR Babysitter

Code Review Checklist

Greploop

More from onsi/gomega

Assertions

Async

Composing Matchers

Custom Matchers

Gbytes

Ghttp

Questions about Gexec

Install Gexec

Facts

At a glance

What it does

When your agent uses it

Example prompts

What it can do on your machine

Tool permissions

Runs code

Network

Credentials

Context cost

Safety

SKILL.md

gexec: testing external processes

Compiling binaries

Starting a process

Asserting on exit

Sending signals

Signaling every started session

Asserting on output

End-to-end

Files

Compare with similar skills

Similar skills

More from onsi/gomega

Related

Questions about Gexec