Editor Support

Radiant provides a Language Server (LSP) and VS Code extension for a first-class editing experience: real-time diagnostics, autocompletion, and code formatting.

VS Code Extension

The vscode-radiant package provides a VS Code extension that launches the Radiant LSP. It activates for .radiant files and provides:

• Diagnostics — squiggly lines for lexing, parsing, and semantic errors
• Autocompletion — context-aware completions for keywords, field types, decorators, and config keys
• Formatting — format-on-save with consistent 2-space indentation
• Cross-file validation — errors in one file take other .radiant files into account (e.g., relationship targets)

LSP Server

The LSP server is powered by the Radiant CLI and uses the vscode-languageserver protocol. You start it with:

radiant lsp

This runs on stdio — editors launch it automatically. You typically never run this manually.

Diagnostics

The LSP provides three layers of diagnostics:

1. Lexing Errors

Reported immediately when the lexer cannot tokenise a character:

✖ Lexing errors:
  Unexpected character '!' at line 5, column 3

2. Parsing Errors

Reported when the token stream doesn't match the grammar:

✖ Parsing errors:
  Expecting token of type: "RCurly" but found "Identifier"

3. Semantic Errors

Reported after successful parsing, during compilation. The LSP scans all .radiant files in the workspace for cross-file context:

• Unknown property — a key not in the allowed set for its block
• Unknown field type — a type not in the allowed field type list
• Duplicate collection — two collections with the same name
• Invalid relationship target — relationship("x") where x doesn't exist
• Missing select options — select() with zero arguments

Cross-File Validation

The LSP scans all .radiant files in the workspace to build cross-file context. This means:

• A relationship("users") in posts.radiant validates against the users collection defined in users.radiant
• Duplicate collection names are detected even when collections are in different files
• When you edit one file, diagnostics update across all open files

Autocompletion

The LSP provides context-aware completions based on what you're typing:

Structural Keywords

When typing at the block level (not after a :), you get completions for:

• config, collection, global — top-level block keywords
• core, security, monitoring, adminUI, output — config block keys
• api, prefix, maxBodyBytes, trustedProxies — nested config keys
• auth, cors, rateLimit, headers, secrets, audit, csrfTrustedOrigins — security keys
• strategies, jwt, apiKey, passwordPolicy, lockout — auth keys
• enabled, apiKey, healthCheck, path, requiresAuth, requestId — monitoring keys
• fields — collection field definition key

Field Types

When typing after a : (in a field definition context), you get completions for all 15 field types with documentation:

• text, textarea, richtext, email, password
• boolean, integer, number, date
• select, multiselect, enum
• relationship, json, array, upload

Each completion includes a detail line (e.g., "Stored as TEXT") and documentation.

Decorators

When typing after @, you get decorator completions:

• @unique — Ensure field is unique
• @optional — Mark field as optional
• @default(value) — Set a default value
• @hidden — Hide from API responses
• @index — Add database index

env() Function

The env completion appears in field type contexts with documentation about the env variable resolution pattern.

Formatting

The formatter uses the parser to produce consistent formatting:

• 2-space indentation
• Consistent property separator (no trailing commas/semicolons)
• Multi-line object blocks for nested objects
• Single-line for simple key-value pairs
• Comments preserved and aligned as leading comments

The formatter never formats broken code — if the input has lex or parse errors, the original text is returned unchanged.

Format on Save

In VS Code, enable format-on-save in your settings:

{
  "[radiant]": {
    "editor.formatOnSave": true
  }
}

Related

• DSL Syntax — The grammar the LSP validates against
• Config Block — The keys the LSP autocompletes in config {}
• Collections — The keys the LSP autocompletes in collection {}