Install the Plugin

Writing Style Catalog ships as a Claude Code plugin. The recommended path is the Product on Purpose marketplace; a ZIP fallback covers the Claude.ai / Claude Desktop upload flow.

Prerequisites

• Claude Code for the marketplace path.
• Nothing else: the plugin is self-contained. The writing-instruction-builder skill reads the catalog that ships inside the plugin, so there is no separate data download.

Option A - Product on Purpose marketplace (recommended)

Run these inside Claude Code:

/plugin marketplace add product-on-purpose/agent-plugins
/plugin install writing-style-catalog@product-on-purpose

You add the marketplace by its repo path (product-on-purpose/agent-plugins) and install the plugin by its marketplace identity (writing-style-catalog@product-on-purpose). Those differ by design: the path is the address, the identity is the brand.

Update later with:

/plugin update writing-style-catalog

Option B - Claude.ai and Claude Desktop (ZIP upload)

For clients that take a plugin as an uploaded archive:

1. Download writing-style-catalog-v<version>.zip from the Releases page.
2. Extract it. The archive root holds .claude-plugin/, skills/, and the taxonomy/ catalog the skill reads.
3. Point your client’s plugin setup at .claude-plugin/plugin.json in the extracted folder.

Verify it loaded

Claude Code (Option A)

Confirm the skill resolves:

/writing-style-catalog:writing-instruction-builder voice=pragmatic-architect format=adr

You should get a structured prompt prefix back.

Claude.ai and Claude Desktop (Option B)

These clients have no slash-command listing, so verify conversationally: ask Claude to “describe the pragmatic-architect voice entry from the writing-style-catalog plugin and quote its one_liner.” A correct install answers in the catalog’s own field language (a senior technical voice that leads with tradeoffs and names constraints explicitly); a missing or broken install answers generically or says it cannot find the entry. From here, the Compose an Instruction guide walks through reading and using the output.

Troubleshooting

Keyed to the actual text you will see, so you can match on the error rather than on a description of it.

[ERROR] jsonschema and referencing are required. Run: pip install jsonschema referencing

tools/validate.py aborts on import when its two dependencies are missing. This is repo development tooling, not part of the installed plugin, so you only hit it if you cloned the repository to contribute:

pip install -r requirements-dev.txt

Installing the two named packages alone also works, but the requirements file pins the rest of the toolchain the checks assume.

python: command not found, or Windows opens the Microsoft Store

On Windows, python often is not on PATH even when Python is installed, and typing it can open the Store instead. Use the launcher:

py -3 tools/validate.py
py -3 skills/entry-recommender/scripts/recommend.py --list

Every command in these guides that begins python works with py -3 substituted. If neither resolves, Python is genuinely not installed; the scripts need 3.10 or newer for the str | None syntax they use.

The slash command does not appear after installing

/writing-style-catalog:... not autocompleting usually means the marketplace was added but the plugin was not installed from it. Both steps are required:

/plugin marketplace add product-on-purpose/agent-plugins
/plugin install writing-style-catalog@product-on-purpose

If you installed before a release and are missing something this page describes, update rather than reinstalling: /plugin update writing-style-catalog. The listing tracks a released tag, not main, so a change merged today is not installable until it is tagged and the registry re-pinned.

Entry not found: voice/<id> (run --list to see valid voice ids)

The id does not exist, or exists but is not stable. The recommender and the builder both serve only stable and reference-quality entries, so a draft entry is invisible to them by design. --list shows exactly what is available:

python skills/writing-instruction-builder/scripts/build-instruction.py --list

{"found": false, "error": "unknown axis: <name>"}

The axis argument takes the singular: voice, tone, style, format. Not voices, and not the directory name.

build-instruction.py is missing expected symbol '<name>'; the two skills' versions may be out of sync

recommend.py loads the builder’s parser rather than duplicating it, and checks up front that the symbols it needs are present. Seeing this means the two skills came from different versions, which a partial copy of the repository or a hand-assembled install can cause. Reinstall the plugin, or check library.json to see which versions the two components should be at.