---
title: Editor support
description: A VS Code extension that highlights what a prompt references, in TypeScript and in skill files.
---
The Foundry Prompts extension for VS Code colours each thing a prompt
references: skills, agents, files, commands, templates, arguments, harness
variables, and shell. It reads each harness's own notation, so `/code-review`
in a Claude Code prompt, `$code-review` in a Codex prompt, and
`/skill:code-review` in a Pi prompt are all marked as the same skill. The
rest of the prompt stays a plain string.
**Dark**
**Light**
## In TypeScript and JavaScript
The extension highlights prompts inside the `prompts` tags, as tagged
templates and as plain-string calls:
```typescript
prompts.claude`/code-review @src/auth`;
prompts.codex("use $review");
```
Any object can come before the dialect: `mine.claude` from `assemble`
highlights the same way as `prompts.claude`. A `${}` substitution inside a
prompt is still ordinary TypeScript, and a prompt written inside a
substitution is highlighted too. Other template literals, strings, and
comments are left alone.
In a template literal, notation that only works in a template is written with
backslash escapes: `` \${CLAUDE_SKILL_DIR} `` and `` !\`git status\` ``. The
extension highlights them as written.
## In skill, agent, and rule files
VS Code opens `SKILL.md`, `.claude/agents/*.md`, `.claude/rules/**/*.md`, and
`*.prompt.md` files with their own language ids. The extension reads the body
of each one as a Claude Code template, so arguments, `${CLAUDE_SKILL_DIR}`,
and inline shell are highlighted alongside skills, files, and agents.
**Dark**
**Light**
Frontmatter, code spans, fenced code, and link targets stay plain. Ordinary
markdown, such as a README, is not highlighted at all.
**Dark**
**Light**
## What each harness reads
| Reference | Claude Code | Codex | Pi |
| --- | --- | --- | --- |
| Skill | `/code-review` | `$code-review` | `/skill:code-review`, opening the message |
| Built-in command | `/clear`, opening the message | `/review`, opening the message | `/compact`, opening the message |
| Prompt template | | `/prompts:draft`, opening the message | `/draft`, opening the message |
| File | `@src/auth` | `@src/auth` | `@src/auth` |
| Agent | `@"security (agent)"` | | |
| Argument | `$ARGUMENTS`, `$ARGUMENTS[0]`, `$0`, `$name` | `$ARGUMENTS`, `$1`, `$FILE` | `$1`, `$@` |
| Harness variable | `${CLAUDE_SKILL_DIR}` | | |
| Shell | `` !`git status` `` | `!git status`, as the whole message | `!git status`, as the whole message |
A command only counts when it opens the message. Later in the text,
`/review` is a skill in Claude Code and plain text in Codex. Codex escapes a
literal dollar sign as `$$`.
## Colours
The extension does not ship a theme. Each kind of reference gets a TextMate
scope that stock themes already colour, and the extension's tests check that
every kind stands out from the text around it in Dark+, Light+, and the
GitHub themes that VS Code's 2026 themes take their palette from.
| Kind | Scope |
| --- | --- |
| Skill, template | `entity.name.function.*.prompt` |
| Command | `keyword.control.command.prompt` |
| Agent | `entity.name.tag.agent.prompt` |
| File | `support.type.path.prompt` |
| Argument | `variable.parameter.argument.prompt` |
| Harness variable | `variable.other.constant.environment.prompt` |
| Shell | `keyword.other.shell.prompt` |
To restyle one kind, target its scope in `editor.tokenColorCustomizations`.
"Developer: Inspect Editor Tokens and Scopes" shows the scope under the
cursor.
## Install
The extension is not on a marketplace yet. Build and install it from a
Foundry checkout:
```sh
cd tooling/vscode-extension
bun run build # writes dist/foundry-prompts.vsix
bun run editor:install # installs it into VS Code, replacing any earlier copy
```
Reload open windows afterwards. To remove it, run
`code --uninstall-extension foundry.foundry-prompts`.
Other VS Code builds take the same file through their own CLI, such as
`cursor --install-extension dist/foundry-prompts.vsix --force`. An editor
built on an older VS Code may open skill files as plain markdown; there, only
the TypeScript half works.
## Limits
- **Highlighting only.** A skill or agent looks the same whether or not it
exists. [Linting](/prompts/lint) checks them, through the ESLint, Oxc, or
Biome extension.
- **Custom dialect keys.** `mine.house` from `assemble` is not highlighted,
because nothing in the source says which harness it is.
- **Command files.** VS Code opens `.claude/commands/*.md` as plain markdown,
and highlighting there would colour every README.
- **One line at a time.** A grammar matches line by line, so in a few edge
cases it reads a prompt differently from the parser. For example, a
command on the line after the opening backtick is highlighted as a skill.
The extension's README lists each case.
## Working on the extension
The extension lives in `tooling/vscode-extension`. Run the "Prompts extension"
launch configuration (F5) from the repository root to open a window with only
this extension loaded, on its sample files. `src/grammar.ts` builds the
grammars; after changing it, run `bun run grammar` and reload that window.
The tests run every grammar through a TextMate engine and compare what it
highlights with what the `@foundry/prompts` parser reads, for each harness.