.|'''.|   ||          '||
       ||..  '  ...    ... .  ||   ....
        ''|||.   ||   || ||   ||  '' .||    Low-latency code search MCP server
      .     '||  ||    |''    ||  .|' ||    for Rust, C# and Unity projects
      |'....|'  .||.  '||||. .||. '|..'|'
                     .|....'

Sigla helps coding agents find their way around C# and Rust projects. It finds declarations, follows references, and returns the relevant code with a source location, ready to read.

• Find a type or method, see where it's used, or look for implementations of an interface.
• Get short, readable results with source excerpts and locations.
• Look up APIs from referenced .NET assemblies, even when their source isn't available.
• Share one server across several agents and projects, with indexing and refresh handled automatically.

Sigla runs on Linux and works with Cargo workspaces and Unity-generated C# projects. It reads your project files directly, so there's no Unity package to install or editor to keep running.

Local Unity discovery uses ~/Unity/Hub/Editor by default. If the editor belongs to another account or lives elsewhere, pass --unity-editors /path/to/Unity/Hub/Editor. The Sigla service account must be able to read that directory and its editor files.

A few examples

To find...	Query
A type	type:GameManager
Methods belonging to a type	method:* in:GameManager
References to a symbol	uses:GameManager
Calls made inside a method	calls:* in:GameManager.Awake
Implementations of an interface	impl:IParser
Text in part of the project	text:"[Singleton]" path:Assets/Scripts
Source files by name	file:*Parser*.cs
Source paths under a directory	file:src/**/*.rs
Saved and inherited Unity components	instance:MyGame.Health
Only the requested Unity type	instance:MyGame.Health type-match:exact
References to a Unity asset	references:Assets/Weapons/Sword.asset
References used by an asset	dependencies:Assets/Enemies/Enemy.prefab

Getting started

Download the Linux x64 release. C# project discovery also needs a .NET SDK and bubblewrap 0.11 or newer.

To build from source, install a Rust toolchain, a .NET SDK, pkg-config, and libarchive development files (libarchive-dev on Debian/Ubuntu):

cargo install --git https://github.com/apkd/sigla --locked
sigla serve

By default, Sigla may read anywhere your user account can access. Use --root /path/to/projects to restrict it to a directory, and repeat --root to allow several directories.

Remote mode uses --allow-repo 'https://github.com/owner/*' for anonymous public access. Add --allow-repo-private 'https://github.com/owner/private-repo' to permit authenticated access to a repository. These rules also apply to Git package dependencies. Recoverable discovery and dependency problems go to server logs; query responses contain only results or request failures.

Selected Git LFS inputs are downloaded into a verified cache. Unavailable objects are skipped and retried during later preparation; an unreadable plugin does not discard the Unity project graph.

Local .NET discovery and restore run through bubblewrap with the checkout read-only. Standard SDK outputs, generated sources, and package caches go into Sigla's cache. Existing NuGet user configuration remains readable. Custom targets that require checkout writes produce a discovery diagnostic; Sigla falls back to readable sources. Remote .NET discovery uses its existing cached filesystem overlay.

Connect your coding agent to http://127.0.0.1:7331/mcp. For Codex, add this to ~/.codex/config.toml:

[mcp_servers.sigla]
url = "http://127.0.0.1:7331/mcp"

The agent gets three tools. Each takes project, a local project path or, in remote mode, a repository URL with an optional #branch, #tag, or full #commit ID. Tags take precedence over branches with the same name, as in Git revision lookup. Use #refs/heads/name or #refs/tags/name to select one explicitly. Lightweight and annotated tags must point to commits. Branches and tags refresh periodically; commit IDs stay pinned. Fetching a historical commit requires the server to allow fetching that object. Abbreviated commit IDs and revision expressions such as main~1 are not supported.

Tool	Other arguments	Result
search	query	Symbols, references, text, or file:GLOB paths
browse	Optional path	An adaptive, indented directory tree
view	path, optional mode	File contents; minified by default, or exact

Authentication

To require a bearer token, put a random token of at least 24 characters in a private file:

sigla serve --token-file /path/to/token

Configure your MCP client to send Authorization: Bearer YOUR_TOKEN. For remote hosting, use an HTTPS reverse proxy; Sigla itself serves HTTP. Listening beyond localhost requires a token. Use --allowed-host for the hostname clients connect through, and --allowed-origin if browser access is needed.