Language Server Protocol (LSP)

Get structured code intelligence inside sandboxes: diagnostics (errors and warnings), document symbols, and cross-file symbol search. Works with Python and TypeScript.

Requires the relevant tools in the sandbox image. The everstack-python and everstack-node catalog images include these pre-installed.

Capability Info

GET /v1/sandbox/{sandboxId}/lsp

Returns available languages and operations for this sandbox.

Diagnostics

Get compiler/linter errors and warnings for a file.

GET /v1/sandbox/{sandboxId}/lsp/{lang}/diagnostics?path={path}

Parameters:

• lang: python or typescript
• path: absolute path to the file inside the sandbox

Python -- uses pylint or flake8. Requires pylint or flake8 in the sandbox.

TypeScript -- uses tsc --noEmit. Requires typescript in the sandbox.

Response:

[
  { "line": 12, "severity": "error", "message": "undefined variable 'foo'", "code": "E1101" },
  { "line": 34, "severity": "warning", "message": "unused import 'os'" }
]

Document Symbols

List functions, classes, and variables defined in a file.

GET /v1/sandbox/{sandboxId}/lsp/{lang}/symbols?path={path}

Python -- parses via ast. Covers def, async def, and class.

TypeScript -- grep-based. Covers function, class, const, interface, type, enum.

Response:

[
  { "name": "process_data", "kind": "FunctionDef", "line": 42 },
  { "name": "DataProcessor", "kind": "ClassDef", "line": 10 }
]

Workspace Symbols

Search for functions or classes by name across all files under a path.

GET /v1/sandbox/{sandboxId}/lsp/{lang}/workspace-symbols?query={query}&path={path}

Response:

[
  { "name": "process_data", "file": "/repo/processor.py", "line": 42 },
  { "name": "process_event", "file": "/repo/handlers.py", "line": 8 }
]

As agent tool calls

All three operations are available as MCP/agent tool calls via the Everstack MCP server:

sandbox_lsp_diagnostics(sandbox_id, path, language)
sandbox_lsp_symbols(sandbox_id, path, language)

This means coding agents can call them directly without constructing HTTP requests.

Requirements

The everstack-python and everstack-node catalog snapshots include these pre-installed.