F5 Technical Writing Style Guide

A consolidated reference for F5 technical writers covering voice and tone, formatting, punctuation, procedures, terminology, and accessibility.

Purpose

This guide consolidates F5's previously siloed style guides — Modern Voice, Brand, NGINX, and the F5 Technical Style Guide — into a single, authoritative reference. It is also configured as a knowledge base for the F5 Style GPT agent.

How to use this guide

Each guideline lives in its own file, organized by category. See TOC.md for the full list of topics.

When this guide doesn't cover a topic, consult the fallback guides in this order:

1. Microsoft Style Guide
2. Chicago Manual of Style
3. American Heritage Dictionary (spelling reference)

Language and spelling

This guide follows American English spelling and conventions throughout. Use the American Heritage Dictionary as the spelling reference when in doubt.

Examples of American English preferences:

• organize, not organise
• color, not colour
• license (noun and verb), not licence
• canceled, not cancelled

Date and time formats

Follow American date format conventions. See Dates and times for full guidance.

• Dates: June 17, 2026 (not 17 June 2026)
• Times: 10 a.m. PT (not 10AM or 10:00 AM)
• Availability: 24x7 (not 24/7)

Using as a submodule

To add this guide as a submodule to your documentation repository with the directory name .style-guide:

git checkout -b docs/add-style-guide-submodule
git submodule add https://github.com/F5Docs/style-guide.git .style-guide
git add .gitmodules .style-guide
git commit -m "docs: Add F5 style guide as submodule"
git push -u origin docs/add-style-guide-submodule

Then open a PR as usual.

Cloning a repo that includes this submodule

If you're cloning a repo for the first time, include submodules:

git clone --recurse-submodules <repo-url>

If you already have the repo cloned, initialize the submodule:

git submodule update --init --recursive

Referencing guidelines in your documentation

From your documentation repo, reference guidelines using relative paths to the .style-guide submodule:

See [Capitalization guidance](./.style-guide/formatting/capitalization.md)

Using with AI coding assistants

The F5 Tech Writer Agent instructions live at .style-guide/agent-instructions/f5-tech-writer-agent.md. Reference this file in your CLAUDE.md or .github/copilot-instructions.md. This file defines the assistant's role, workflows (review, copy edit, draft from notes), north stars, mandatory rules, and citation format. It's the single source of truth for agent behavior across every repo that includes this submodule.

For CLAUDE.md, use Claude Code's file import syntax to load the agent instructions directly:

@.style-guide/agent-instructions/f5-tech-writer-agent.md

This is a live reference. Claude Code expands it into context at the start of every session, so there's nothing to keep in sync as the agent instructions evolve.

For .github/copilot-instructions.md, GitHub Copilot doesn't support file imports, so you need to instruct the assistant to read the file:

## Agent instructions
Before responding to any request in this repo, read
`.style-guide/agent-instructions/f5-tech-writer-agent.md` in full. It
defines your role, workflows, north stars, mandatory rules, and citation
format. Treat it as your primary instructions for this repo.

This depends on the assistant actually reading the file before responding, which isn't guaranteed on every turn. Test it in a fresh session: before giving the assistant any specific task, ask it to describe its instructions for the repo. If it accurately describes the workflows and rules from f5-tech-writer-agent.md, the reference is working.

Add repo-specific context — build commands, content structure, linting rules, anything unique to that codebase — below the agent instructions reference, not mixed into it.

Once configured, contributors can ask the assistant to:

• Review a file -- flag style issues, cite the specific guideline each one violates, and suggest fixes.

  Review this file for F5 style: content/path/to/your-file.md

• Copy edit a file -- revise the file in place and list every change made, with the guideline it applies.

  Copy edit this file: content/path/to/your-file.md

• Draft from notes -- turn raw notes into a structured draft. The assistant identifies the content type (how-to, concept, reference, tutorial, etc.), loads the matching template from .style-guide/templates/, and follows its section structure.

  Write a draft from the following notes:

  • explain what an upstream block is in NGINX
  • defines a group of backend servers that NGINX can proxy requests to
  • can include multiple servers with optional weight, max_fails, fail_timeout
  • used with proxy_pass in a server or location block
  • audience: developers new to NGINX

See the copilot-instructions.md file in the nginx/documentation repo for a working example.

Updating the submodule

To fetch the latest updates from the style guide repository:

git checkout -b chore/sync-style-guide
git submodule update --remote .style-guide
git add .style-guide
git commit -m "chore: Update F5 style guide submodule"
git push -u origin chore/sync-style-guide

Then open a PR as usual.

Contributing

See CONTRIBUTING.md for guidance on adding or updating guidelines. Use the template in templates/guideline-template.md for all new files.