contentrx-lsp

Inline content-design diagnostics in any LSP-capable editor — VS Code, Cursor, Zed, Neovim, JetBrains IDEs.

ContentRX's Language Server reads JSX/TSX source, pulls out UI copy (JSX text content and stringy JSX attributes), and surfaces violations of the ContentRX content model directly in the editor's problems panel as you type.

Install

uvx contentrx-lsp       # one-shot, no persistent install
pipx install contentrx-lsp
pip install contentrx-lsp

Most editors don't need you to install this by hand — use the ContentRX VS Code / Cursor extension and it will launch the server on first activation.

Configure

Set CONTENTRX_API_KEY in the environment the editor runs with. Generate a key at contentrx.io/dashboard.

export CONTENTRX_API_KEY=cx_...

For local development against npm run dev:

export CONTENTRX_API_URL=http://localhost:3000
export CONTENTRX_INSECURE_HTTP=1

What it emits

For every extracted string, the server calls /api/check and emits one LSP diagnostic per violation:

• violation verdict → severity Warning (yellow squiggle)
• review_recommended verdict → severity Information (blue squiggle)
• pass verdict → no diagnostic

Each diagnostic carries the standard ID as the diagnostic code and points at the full rationale on docs.contentrx.io.

How it works

1. initialize handshake advertises incremental text sync and UTF-16 position encoding — the LSP spec's default, matches every editor.
2. didOpen / didChange update the in-memory document state. Lint jobs debounce for 400ms so rapid typing doesn't thrash the API.
3. A per-document token bucket caps API calls at 2 per second.
4. Tree-sitter parses the TSX source; string extraction is scoped to JSX text children and allow-listed copy attributes (alt, aria-label, placeholder, title, tooltip, label, …).
5. /api/check runs server-side — the LSP is a thin HTTP client, no engine imports. Results map to LSP diagnostics via src/contentrx_lsp/diagnostics.py.

Architecture

Three surfaces talk to the same /api/check:

• MCP server (contentrx-mcp) — Claude Code, Cursor chat, Claude desktop
• LSP server (contentrx-lsp) — inline diagnostics
• CLI (contentrx-cli) — terminal + CI

One source of truth for verdicts; no per-surface drift.

Try it

With an API key set, point any LSP client at contentrx-lsp and open a TSX file. The reference test case:

export function SignInButton() {
  return <button>Click here</button>;
}

Expected diagnostic: ACT-01 (generic CTA verb) on the Click here text range.