Agent skill

Gbytes

Testing streaming io buffers with gbytes — gbytes.NewBuffer() (an io.Writer also returned by gexec sessions), the Say(regexp) matcher that forward-scans from a moving read cursor, the canonical…

MITAuto-check passedDevelopment

Install Gbytes

skills CLI

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

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

GitHub CLI

$ gh skill install onsi/gomega gbytes --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/gbytes .claude/skills/gbytes && 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 "gbytes" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gbytes into .claude/skills/gbytes/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gbytes", 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/gbytes

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 gbytes -a codex

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

GitHub CLI

$ gh skill install onsi/gomega gbytes --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/gbytes .agents/skills/gbytes && 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 "gbytes" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gbytes into .agents/skills/gbytes/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gbytes", 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 gbytes -a cursor

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

GitHub CLI

$ gh skill install onsi/gomega gbytes --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/gbytes .cursor/skills/gbytes && 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 "gbytes" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gbytes into .cursor/skills/gbytes/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gbytes", 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/gbytes

--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 gbytes -a gemini-cli

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

GitHub CLI

$ gh skill install onsi/gomega gbytes --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/gbytes .gemini/skills/gbytes && 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 "gbytes" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gbytes into .gemini/skills/gbytes/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gbytes", 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 gbytes

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 gbytes -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/gbytes .github/skills/gbytes && 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 "gbytes" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gbytes into .github/skills/gbytes/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gbytes", 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 gbytes -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 gbytes --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/gbytes .opencode/skills/gbytes && 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 "gbytes" agent skill from https://github.com/onsi/gomega/tree/master/plugins/gomega/skills/gbytes into .opencode/skills/gbytes/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gbytes", 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: gbytes
GitHub stars: 2.4k
Token cost: ~1.5k tokens
SKILL.md length: 517 words
Files: 1
Skills in repo: 12
Repo updated: Sep 24, 2026
First seen: Oct 7, 2026
Licence: MIT

At a glance

Testing streaming io buffers with gbytes — gbytes.NewBuffer() (an io.Writer also returned by gexec sessions), the Say(regexp) matcher that forward-scans from a moving read cursor, the canonical…

Asserting on streaming
SKILL.md covers The buffer, The Say matcher, The canonical streaming… and Handling branches, plus 2 more sections
Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
Incremental output (process stdout/stderr

What it does

Gbytes is an agent skill from onsi/gomega. Testing streaming io buffers with gbytes — gbytes.NewBuffer() (an io.Writer also returned by gexec sessions), the Say(regexp) matcher that forward-scans from a moving read cursor, the canonical Eventually(buffer).Should(Say(...)) streaming pattern, sequential cursor-advancing Say calls, Contents(), BufferWithBytes/BufferReader, buffer.Detect for branching, and TimeoutReader/Writer/Closer for testing blocking io.Reader/Writer/Closer. Use when asserting on streaming or incremental output (process stdout/stderr, API…

Its SKILL.md is about 1.5k 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 streaming
Incremental output (process stdout/stderr
Io.Readers) rather than a complete value

Example prompts

“/gbytes”

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
No scripts in the folder and no shell commands in SKILL.md (its code samples are 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

Gbytes loads about 1.5k tokens when it runs. Until then it costs about 144 tokens; SKILL.md has 517 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it: ~144
When it runs · the whole SKILL.md, loaded when a task matches: ~1.5k

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). 517 words, ~1,495 tokens.

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

name: gbytes
description: Testing streaming io buffers with gbytes — gbytes.NewBuffer() (an io.Writer also returned by gexec sessions), the Say(regexp) matcher that forward-scans from a moving read cursor, the canonical Eventually(buffer).Should(Say(...)) streaming pattern, sequential cursor-advancing Say calls, Contents(), BufferWithBytes/BufferReader, buffer.Detect for branching, and TimeoutReader/Writer/Closer for testing blocking io.Reader/Writer/Closer. Use when asserting on streaming or incremental output (process stdout/stderr, API streams, io.Readers) rather than a complete value.

gbytes: testing streaming buffers

gbytes provides *gbytes.Buffer, an in-memory io.Writer (and io.Reader/io.Closer) that captures everything written to it, plus the Say matcher for making ordered assertions against streaming data as it arrives. Pairs naturally with gomega:async (poll with Eventually) and gomega:gexec (a session's .Out/.Err are *gbytes.Buffers, and the session itself is a BufferProvider). Docs: https://onsi.github.io/gomega/#gbytes-testing-streaming-buffers.

import (
	. "github.com/onsi/gomega"
	"github.com/onsi/gomega/gbytes"
)

The buffer

gbytes.NewBuffer() returns an empty *gbytes.Buffer. Hand it to anything that wants an io.Writer and it accumulates the bytes:

buffer := gbytes.NewBuffer()
go client.AttachToDataStream(buffer) // client writes to buffer concurrently

gbytes.BufferWithBytes(b []byte) — seed a buffer with already-captured bytes.
buffer.Contents() []byte — all bytes ever written, regardless of cursor position. Use this for whole-buffer assertions (Expect(buffer.Contents()).To(ContainSubstring(...))).
buffer.Close() / buffer.Closed() — mark a buffer done. Writes to a closed buffer error. A closed buffer tells Eventually to give up (see below).

The `Say` matcher

gbytes.Say(pattern, args...) takes a regular expression (optionally fmt.Sprintf-formatted with args) and matches against the buffer's unread portion:

Expect(buffer).To(gbytes.Say(`hello \w+`))

Say is cursor-based, not whole-buffer. Each buffer carries an opaque read cursor you cannot access. When Say matches, it fast-forwards the cursor to just past the match. The next Say only sees bytes after that point. This is what makes ordered assertions work — and the gotcha below.

The canonical streaming pattern: `Eventually` + `Say`

Streaming output arrives over time, so poll the buffer with Eventually (gomega:async). Each successful Say advances the cursor, so successive Says assert on successive output in order:

Eventually(buffer).Should(gbytes.Say(`Attached as client \d+`))

client.ReticulateSplines()
Eventually(buffer).Should(gbytes.Say(`reticulating splines`))

client.EncabulateRetros(7)
Eventually(buffer).Should(gbytes.Say(`encabulating 7 retros`))

Because the cursor only moves forward, this counts repeats correctly — these two assertions pass only if reticulating splines appears twice:

client.ReticulateSplines()
Eventually(buffer).Should(gbytes.Say(`reticulating splines`))
client.ReticulateSplines()
Eventually(buffer).Should(gbytes.Say(`reticulating splines`))

And consequently this (counterintuitively) passes — the first Say consumed the match:

Eventually(buffer).Should(gbytes.Say(`reticulating splines`))
Consistently(buffer).ShouldNot(gbytes.Say(`reticulating splines`))

Say works on a *gbytes.Buffer or any BufferProvider (anything with a Buffer() *gbytes.Buffer method, e.g. a gexec.Session), so Eventually(session).Should(gbytes.Say(...)) works directly.

Handling branches

When the test must react to whichever output arrives, use buffer.Detect(regexp, args...), which returns a channel that fires once on match (and fast-forwards the cursor). Always CancelDetects() to clean up the spawned goroutines:

client.Authorize()
select {
case <-buffer.Detect("You are not logged in"):
	client.Login()
case <-buffer.Detect("Success"):
	// carry on
case <-time.After(time.Second):
	Fail("timed out waiting for output")
}
buffer.CancelDetects()

Show full SKILL.md (209 more words)Show less

Testing `io.Reader`/`io.Writer`/`io.Closer`

These interfaces are expected to block, so calling Read/Write/Close directly in a test risks hanging forever. Wrap them with timeouts; the wrappers return gbytes.ErrTimeout if the operation doesn't complete in time:

p := make([]byte, 5)
_, err := gbytes.TimeoutReader(reader, time.Second).Read(p)
Expect(err).NotTo(HaveOccurred())

gbytes.TimeoutReader, gbytes.TimeoutWriter, and gbytes.TimeoutCloser each wrap the matching interface. To use Say against an io.Reader, wrap it with gbytes.BufferReader(reader) — it launches an io.Copy goroutine into a fresh buffer (closed when the copy completes). Because the copy is async you must use Eventually:

Eventually(gbytes.BufferReader(reader)).Should(gbytes.Say("abcde"))

Gotchas

Say takes a regexp — escape metacharacters. (, ), ., [, +, ?, \d, etc. are regex syntax. To match a literal splines (v2) write gbytes.Say(splines (v2)). The pattern is compiled with regexp.MustCompile, so a bad pattern panics.
The cursor only moves forward. You cannot re-match output an earlier Say already consumed. If you need to assert on the whole buffer, use buffer.Contents() with a string matcher (gomega:matchers) instead of Say.
Pair Say with Eventually for live streams; use plain Expect only on an already-complete buffer. A bare Expect(buffer).To(Say(...)) checks the buffer once, right now — it will flake if the data hasn't arrived yet.
A closed buffer aborts Eventually early. Once Close() is called, a pending Say can never succeed on new data, so the matcher signals Eventually/Consistently to stop polling and fail immediately rather than wait out the timeout.

Files

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

Open the folder on GitHubat commit 37fa900

Compare with similar skills

Gbytes 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.

Gbytes compared with similar skills
Skill	Stars	Used in	Tokens	Auto-check	Licence	Repo updated
Gbytes this skillonsi/gomega	2.4k	—	~1.5k	Automated safety check: Pass	MIT	13 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 Gbytes

What does Gbytes do?

Testing streaming io buffers with gbytes — gbytes.NewBuffer() (an io.Writer also returned by gexec sessions), the Say(regexp) matcher that forward-scans from a moving read cursor, the canonical…. Gbytes is an agent skill from onsi/gomega.Reader/Writer/Closer.

When should I use Gbytes?

Gbytes fits situations like: asserting on streaming; incremental output (process stdout/stderr; io.Readers) rather than a complete value.

How do I install Gbytes in Claude Code?

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

How do I install Gbytes in Codex?

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

Can I use Gbytes 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 gbytes -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/gbytes, .gemini/skills/gbytes, .github/skills/gbytes and .opencode/skills/gbytes in your project.

What does Gbytes need to run?

SKILL.md names no scripts, command-line tools or credentials: Gbytes is instructions for the agent only.

Does Gbytes 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 Gbytes 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 Gbytes use?

Gbytes 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 Gbytes use?

About 1.5k tokens (SKILL.md is roughly 6k 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 Gbytes?

Skills that share tags, products or a category with Gbytes: 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 Gbytes?

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.

Gbytes

Install Gbytes

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

gbytes: testing streaming buffers

The buffer

The `Say` matcher

The canonical streaming pattern: `Eventually` + `Say`

Handling branches

Testing `io.Reader`/`io.Writer`/`io.Closer`

Gotchas

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

Gexec

Ghttp

Questions about Gbytes

Install Gbytes

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

gbytes: testing streaming buffers

The buffer

The Say matcher

The canonical streaming pattern: Eventually + Say

Handling branches

Testing io.Reader/io.Writer/io.Closer

Gotchas

Files

Compare with similar skills

Similar skills

More from onsi/gomega

Related

Questions about Gbytes

The `Say` matcher

The canonical streaming pattern: `Eventually` + `Say`

Testing `io.Reader`/`io.Writer`/`io.Closer`