Formatters, LSP, and References#

Neoism Agent can query the same language intelligence used by the editor. It also preserves oversized tool output as artifacts so an agent can inspect exact details without replaying megabytes into every model request.

LSP#

The Agent server exposes these language-server operations:

• Server status.
• Hover information.
• Go to definition and implementation.
• Find references.
• Document and workspace symbols.
• Diagnostics.
• Document highlights.
• Folding ranges.
• Selection ranges.
• Formatting.
• Code actions.
• Call hierarchy preparation, incoming calls, and outgoing calls.
• Document touch/update and server shutdown.

The native lsp tool wraps these operations behind one typed interface. It accepts a file, zero-based line, and zero-based UTF-8 byte column where a position is required.

Install language servers#

Open Neoism's hamburger menu in the top chrome and choose Extensions. The Language Servers tab is backed by the same runtime adapter registry used by the editor and Agent tools. It shows built-in integrations, installed servers, and servers Neoism can install from its extension catalog.

Choose Install on a supported language server. Neoism downloads it into its managed extension directory, so it does not modify your system package manager or require the executable to be added globally to $PATH. The same page provides uninstall and retry actions.

When you open a file whose matched server is missing, Neoism can also present an install prompt. That prompt and the Extensions page use the same runtime registry and installer; they are two entrances to the same system.

The Extensions page also contains MCP Servers, built-in Syntax Parsers, and Kernels. Syntax parsers compiled into Neoism are marked built-in and require no download.

Neoism resolves an LSP executable from its managed extensions, an explicit configured command, or the host environment as supported by the adapter. Live server state appears in the editor status area; multi-server files can report more than one attached server.

For Yarn Plug'n'Play TypeScript projects, Neoism searches from a nested TypeScript package up to the opened workspace boundary for Yarn's canonical .pnp.cjs, then explicitly loads the matching .yarn/sdks/typescript/lib into the managed typescript-language-server. LSP status and remote editor snapshots expose whether TypeScript came from that Yarn SDK, an explicit initializationOptions.tsserver.path, or the language server's normal fallback, including SDK path/version when available. If the patched SDK is missing, Neoism keeps normal TypeScript/JavaScript fallback service running and reports a degraded warning with the one-time command corepack yarn dlx @yarnpkg/sdks base; it never executes that networked command or mutates the project itself. Project SDK probes are cached for two seconds, after which appearance or replacement changes client identity and restarts on the next operation.

Advanced language-server configuration#

Most users should install servers through Extensions. The lsp block is for disabling an adapter, overriding one, or defining a custom server that is not in the catalog.

{
  "agent": {
    "lsp": {
      "company-rust": {
        "name": "Company Rust Analyzer",
        "command": ["/opt/company/bin/rust-analyzer"],
        "language": "rust",
        "documentLanguageId": "rust",
        "extensions": ["rs"],
        "markers": ["Cargo.toml"],
        "env": { "RUST_LOG": "error" }
      }
    }
  }
}

Project neoism.json uses the direct "lsp" block.

Set an adapter ID to false, or use "enabled": false, to disable it. A configured definition can reference and override a built-in adapter with adapter; custom definitions must provide a valid route and stdio command or TCP endpoint.

Diagnostics and code actions#

LSP diagnostics are published into session/client events after relevant tools run. An agent can inspect current diagnostics and request code actions, but applying an edit still goes through normal edit tools and permissions.

Formatting#

Agent-side formatting currently uses the attached language server's formatting capability. Install the language server through Extensions, then use editor formatting or the Agent lsp tool. The Agent server does not currently expose a separate formatter inventory.

Tool-output references#

Neoism centrally truncates oversized tool output. When output exceeds the safe inline budget, it writes the complete result to a tool-output artifact and returns:

• A bounded preview.
• truncated: true metadata.
• An outputPath.
• Artifact metadata and an artifact:// reference when available.

The model receives the compact reference rather than repeatedly ingesting the full output. It can use artifact-reading/search tools to inspect only the relevant region.

This applies to large shell, search, web, and other tool results. A tool's own pagination truncated flag is distinct from Neoism spilling the complete output to disk.

Source references#

Message file parts can carry path ranges, selected text, symbols, and diagnostics. These references let editor context flow into a prompt without flattening every item into anonymous text.

Troubleshooting#

• If LSP status is empty, open hamburger menu → Extensions → Language Servers, install the matching server, and reopen or touch the file.
• If installation fails, use the extension card's retry action and verify the required download toolchain/network is available.
• If hover/references fail on a newly edited document, touch/update the document or save it so the server sees current text.
• A zero-based byte column differs from a visual glyph column for non-ASCII text.
• If formatting returns no edits, the language server may not advertise formatting support.
• Read an artifact's outputPath or artifact:// reference when a tool preview says it was truncated.

See Attachments and Troubleshooting.