LSP Skill

Language Server Protocol skill providing code intelligence via Microsoft multilspy.

TypeScript: Coming soon. The LSP skill is Python-only today (webagents.agents.skills.local.lsp). Track the gap in the parity matrix. Until it lands, agents that need LSP intelligence in a TypeScript stack should call out to a sidecar Python agent that hosts LSPSkill.

Overview

The LSP skill provides code intelligence capabilities:

Go to Definition - Find where a symbol is defined

Find References - Find all usages of a symbol

Code Completions - Get contextual completions at cursor

Hover Information - Get type info and documentation

Document Symbols - List all symbols in a file

Supported Languages

Language	Extensions	Notes
Python	`.py`, `.pyw`, `.pyi`	Pyright/Pylance
TypeScript	`.ts`, `.tsx`	tsserver
JavaScript	`.js`, `.jsx`, `.mjs`, `.cjs`	tsserver
Java	`.java`	Eclipse JDT
Rust	`.rs`	rust-analyzer
Go	`.go`	gopls
C#	`.cs`	OmniSharp
Dart	`.dart`	Dart Analysis Server
Ruby	`.rb`	Solargraph
Kotlin	`.kt`, `.kts`	kotlin-language-server

Language is automatically detected from file extension.

Configuration

skills:
  lsp:
    project_root: "."  # Path to project root (default: current directory)

SDK API

// LSPSkill is Python-only today. Recommended TS workaround:
// expose a Python sidecar agent at /agents/lsp-helper that hosts the LSPSkill,
// and call it from your TS agent via NLISkill or DynamicRoutingSkill.

import { BaseAgent } from 'webagents';
import { NLISkill } from 'webagents/skills/nli';

const agent = new BaseAgent({
  name: 'code-agent',
  skills: [new NLISkill({ defaultAgentUrl: 'https://internal/agents/lsp-helper' })],
});

Tools

`goto_definition`

Find the definition of a symbol at a given position.

result = await skill.goto_definition(
    file_path="src/main.py",
    line=10,        # 1-indexed
    column=5,       # 1-indexed
    language=None   # auto-detected from extension
)
# Returns: {"found": True, "file": "src/utils.py", "line": 5, "column": 1}

`find_references`

Find all references to a symbol.

result = await skill.find_references(
    file_path="src/main.py",
    line=10,
    column=5,
    include_declaration=True,
    language=None
)
# Returns: {"count": 3, "references": [{"file": "...", "line": ..., "column": ...}]}

`get_completions`

Get code completions at cursor position.

result = await skill.get_completions(
    file_path="src/main.py",
    line=10,
    column=5,
    language=None
)
# Returns: {
#   "count": 15, 
#   "completions": [
#     {"label": "append", "kind": 2, "detail": "(item) -> None", ...}
#   ]
# }

`get_hover`

Get hover information (type info, docs) for a symbol.

result = await skill.get_hover(
    file_path="src/main.py",
    line=10,
    column=5,
    language=None
)
# Returns: {"found": True, "content": "def greet(name: str) -> str"}

`get_document_symbols`

Get all symbols defined in a file.

result = await skill.get_document_symbols(
    file_path="src/main.py",
    language=None
)
# Returns: {
#   "count": 5, 
#   "symbols": [
#     {"name": "greet", "kind": "Function", "line": 2, "parent": None},
#     {"name": "name", "kind": "Variable", "line": 3, "parent": "greet"}
#   ]
# }

Slash Commands

Command	Description
`/lsp`	Show LSP status including active servers and supported languages

Example output:

**LSP Status**
Project: /Users/me/myproject
Active servers: python, typescript
Supported: python, typescript, javascript, java, rust, go, csharp, dart, ruby, kotlin

Usage Examples

Agent Chat

User: What function is called at line 45 of main.py?

Agent: [uses get_hover tool]
The function at line 45 is `process_data(items: List[str]) -> Dict[str, int]`
which processes a list of strings and returns a frequency dictionary.

User: Where is that function defined?

Agent: [uses goto_definition tool]
`process_data` is defined at src/utils.py:23

Programmatic Use

// LSPSkill is Python-only today. From a TypeScript agent, delegate to a
// Python sidecar via NLI:
const refs = await fetch('https://internal/agents/lsp-helper/lsp/find-references', {
  method: 'POST',
  headers: { 'content-type': 'application/json' },
  body: JSON.stringify({ file_path: 'src/api.py', line: 50, column: 10 }),
}).then((r) => r.json());

console.log(`Found ${refs.count} references`);
for (const ref of refs.references) {
  console.log(`  ${ref.file}:${ref.line}`);
}

API Notes

Line/Column Indexing

API uses 1-indexed positions (line 1 is the first line)

Internally converts to 0-indexed for LSP protocol

Results are converted back to 1-indexed for display

Lazy Initialization

Language servers are started on first use and cached. This means:

No startup delay when skill loads

First request for a language may take longer

Subsequent requests are fast

Call cleanup() to shut down all servers when done.

Error Handling

Scenario	Behavior
Unsupported extension	Raises `ValueError` with list of supported extensions
Definition not found	Returns `{"found": False, "message": "..."}`
No completions	Returns `{"count": 0, "completions": []}`
Server errors	Logged; may raise exceptions

Symbol Kinds

The get_document_symbols tool returns a kind field with these values:

Kind	Description
File	File
Module	Module
Namespace	Namespace
Package	Package
Class	Class
Method	Method
Property	Property
Field	Field
Constructor	Constructor
Enum	Enum
Interface	Interface
Function	Function
Variable	Variable
Constant	Constant
String	String literal
Number	Number literal
Boolean	Boolean literal
Array	Array
Object	Object literal
Struct	Struct
Event	Event
Operator	Operator
TypeParameter	Type parameter

Dependencies

multilspy>=0.0.15

Install with:

pip install multilspy

Architecture

webagents/agents/skills/local/lsp/
├── __init__.py      # Export LSPSkill
├── skill.py         # LSPSkill class wrapping multilspy
├── languages.py     # Language detection and configuration
└── README.md        # Developer documentation