Language servers

omdsh can hand the agent a read-only lsp tool backed by real language servers. The tool has four operations — goToDefinition, findReferences, goToImplementation, and hover — and omdsh does not implement the protocol itself: the DeepSeek Harness dsh-lsp seam, the dsh-lsp-stdio host, and the dsh-tool-lsp tool own server lifecycle, framing, and result normalization.

Nothing is mounted until you configure at least one server, so a session without language servers never shows an lsp tool that can only fail.

Prerequisites

Install the server you want and make sure its executable is on PATH. omdsh ships no language server and installs none. Common choices:

Language	Server	Command
TypeScript / JavaScript	`typescript-language-server`	`typescript-language-server --stdio`
Python	`pyright`	`pyright-langserver --stdio`
Go	`gopls`	`gopls`
Rust	`rust-analyzer`	`rust-analyzer`
C / C++	`clangd`	`clangd`

Configure servers

Write lsp.json in the same places omdsh reads mcp.json: $OMDSH_HOME/lsp.json (or $DSH_HOME/lsp.json, then ~/.dsh/lsp.json) for every project, and <project>/.dsh/lsp.json for one project. A project definition overrides a user definition with the same server name.

{
  "servers": {
    "typescript": {
      "command": "typescript-language-server",
      "args": ["--stdio"],
      "extensionToLanguage": {
        ".ts": "typescript",
        ".tsx": "typescriptreact"
      }
    },
    "python": {
      "command": "pyright-langserver",
      "args": ["--stdio"],
      "extensionToLanguage": { ".py": "python" }
    }
  }
}

Field	Required	Meaning
`command`	yes	Executable name resolved on `PATH`, or an absolute path.
`extensionToLanguage`	yes	Lowercase leading-dot extension to LSP language id. At least one entry.
`args`	no	Arguments passed to the executable.
`env`	no	Extra environment merged over the inherited one. Credential-shaped names and `DSH_*` are not forwarded.
`initializationOptions`	no	Static `initialize` options for the server.
`configuration`	no	Static answer to every `workspace/configuration` request.
`enabled`	no	Set `false` to keep a server in the file without mounting it.

${NAME} and ${NAME:-fallback} expand from the environment, so a machine-specific path or binary name can stay out of the file:

{ "servers": { "typescript": {
  "command": "${LSP_BIN:-typescript-language-server}",
  "extensionToLanguage": { ".ts": "typescript" }
} } }

Restart omdsh after editing lsp.json. omdsh --dump-config lists the lsp, lsp-stdio, and tool-lsp rows, and /tools lists the lsp tool.

What the agent gets

The agent calls lsp with an operation, a file path, and one-based line and character coordinates. Navigation returns path:line:character locations grouped by file; findReferences always includes the declaration, so impact analysis never misses the defining site. Hover returns normalized text. Empty results are successful no-result answers, not errors.

Use it when textual search is ambiguous — a common symbol name, an overloaded method, or a change that needs exact call sites — and keep grep and read for ordinary navigation.

Behavior and limits

omdsh resolves every configured executable at startup. A missing binary or a malformed lsp.json fails the launch with a labelled error instead of silently disabling navigation.
Each workspace gets one pooled server process, started on the first query for that workspace. Queries to one server run one at a time; different workspaces run in parallel.
Each query opens the current source text transiently and closes it afterwards, so the server always sees what is on disk and no document state accumulates.
A configured server runs with the same filesystem and process authority as omdsh. The host rejects query sources that are missing, non-regular, non-UTF-8, oversized, or outside the workspace, but it adds no sandbox of its own — treat a configured server like any other executable you trust.
A query for an extension no configured server maps fails with LSP_UNAVAILABLE, which the agent can read and route around.