Typescript Lsp

TypeScript LSP Skill

Purpose

LSP-style queries over TypeScript's native API (TS7 typescript/unstable/async). The CLI uses TypeScript's built-in checker directly — no typescript-language-server process, no tsserver.js, no JSON-RPC lifecycle. You supply a method and params, get the result.

Use this when you need semantic understanding of TypeScript/JavaScript code: type info, symbol lists, definitions, or completions.

When to Use

These are the only four methods supported. Unsupported methods return "error": "Unsupported method: <method>".

For non-LSP tasks: use Glob for file finding, Grep for text search, and git log for history.

Usage

Single command with JSON input. Two modes via mode discriminant:

plaited typescript-lsp '<json>'
echo '<json>' | plaited typescript-lsp
plaited typescript-lsp --schema input    # JSON Schema for input
plaited typescript-lsp --schema output   # JSON Schema for output

Modes

Execute Mode

Open a file and send LSP method requests in a single session. The CLI handles file opening and parsing — you supply the method and params.

{
  "mode": "execute",
  "file": "src/app.ts",
  "rootDir": ".",
  "requests": [
    { "method": "textDocument/hover", "params": { "textDocument": { "uri": "file:///abs/path/src/app.ts" }, "position": { "line": 5, "character": 10 } } },
    { "method": "textDocument/definition", "params": { "textDocument": { "uri": "file:///abs/path/src/app.ts" }, "position": { "line": 20, "character": 3 } } }
  ]
}

Fields:

• mode — must be "execute"
• file — path to TypeScript/JavaScript file (required)
• rootDir — workspace root for file:// URI resolution (defaults to .)
• requests — array of request objects, each with:
  • method — one of the four supported methods
  • params — method-specific params object (see LSP spec for shape)

URI construction: The params for methods like textDocument/hover require a textDocument.uri field. Construct it as file://<absolute-path-to-file>.

Response shape: Output shapes are method-specific. hover returns a flattened { name, kind, type, documentation, tags } rather than the LSP standard { contents, range }. documentSymbol returns entries with a flat range: [start, end] offset pair. definition returns the standard LSP array of { uri, range: { start, end } }. Inspect actual fields per method rather than assuming a single shape.

Discover Mode

Return a list of supported methods. No file required.

{
  "mode": "discover",
  "rootDir": "."
}

Fields:

• mode — must be "discover"
• rootDir — workspace root (defaults to .)

Output Format

Execute output

{
  "mode": "execute",
  "file": "src/utils/key-mirror.ts",
  "results": [
    {
      "method": "textDocument/hover",
      "result": {
        "name": "keyMirror",
        "kind": 2,
        "type": "(inputs: T) => { [K in T[number]]: K }",
        "documentation": "Creates immutable object with self-referential key-value pairs.\nType-safe string constants for TypeScript.",
        "tags": [
          { "name": "template", "text": "Keys - String literal tuple" },
          { "name": "param", "text": "inputs - Strings to use as keys and values" },
          { "name": "returns", "text": "Frozen object where each key equals its value" }
        ]
      }
    },
    {
      "method": "textDocument/references",
      "error": "Unsupported method: textDocument/references"
    }
  ]
}

Each result corresponds to the request at the same index. Failed requests (including unsupported methods) include an error field instead of result. Other requests still run.

Method-specific output shapes vary. hover returns { name, kind, type, documentation, tags } (not the LSP-standard { contents, range }). definition returns the standard LSP array of { uri, range: { start, end } }. documentSymbol returns entries with flat range: [start, end] offset pairs.

Discover output

{
  "mode": "discover",
  "capabilities": [
    { "method": "textDocument/documentSymbol", "capability": "documentSymbolProvider" },
    { "method": "textDocument/hover", "capability": "hoverProvider" },
    { "method": "textDocument/completion", "capability": "completionProvider" },
    { "method": "textDocument/definition", "capability": "definitionProvider" }
  ]
}

The capabilities list is fixed — these four methods are always supported. A method not listed here will return "error": "Unsupported method: <method>".

Common Workflows

Get type info at position

plaited typescript-lsp '{"mode":"execute","file":"src/utils/parser.ts","requests":[{"method":"textDocument/hover","params":{"textDocument":{"uri":"file:///home/user/project/src/utils/parser.ts"},"position":{"line":42,"character":10}}}]}'

List all symbols in a file

plaited typescript-lsp '{"mode":"execute","file":"src/utils/parser.ts","requests":[{"method":"textDocument/documentSymbol","params":{"textDocument":{"uri":"file:///home/user/project/src/utils/parser.ts"}}}]}'

Go to definition

plaited typescript-lsp '{"mode":"execute","file":"src/utils/parser.ts","requests":[{"method":"textDocument/definition","params":{"textDocument":{"uri":"file:///home/user/project/src/utils/parser.ts"},"position":{"line":15,"character":8}}}]}'

Batch: hover + definition + symbols in one session

plaited typescript-lsp '{"mode":"execute","file":"src/utils/parser.ts","requests":[
  {"method":"textDocument/hover","params":{"textDocument":{"uri":"file:///home/user/project/src/utils/parser.ts"},"position":{"line":10,"character":13}}},
  {"method":"textDocument/definition","params":{"textDocument":{"uri":"file:///home/user/project/src/utils/parser.ts"},"position":{"line":10,"character":13}}},
  {"method":"textDocument/documentSymbol","params":{"textDocument":{"uri":"file:///home/user/project/src/utils/parser.ts"}}}
]}'

Discover server capabilities

plaited typescript-lsp '{"mode":"discover"}'

Notes

• All positions are 0-indexed (line 0 = first line, character 0 = first column).
• The file is opened and parsed automatically. You do not send didOpen notifications.
• Method-specific output shapes vary (see "Execute output" above); inspect the actual fields rather than assuming a single shape across methods.
• For a complete reference of LSP method names and their parameter shapes, consult the LSP Specification.
• Use plaited typescript-lsp --schema input to see the exact JSON Schema of accepted input.

Exit Codes

• 0 — the tool ran (requests may still have failed individually; check each result for an error field rather than relying on the exit code to detect per-request failures).
• 2 — bad input or tool error.

Per-request failures (unsupported methods, out-of-range positions, etc.) are reported inline as "error": "<message>" on the corresponding result and do not change the process exit code. Inspect results[].error to detect partial failures.