@onimaxxing/sussy-seeds-mcp

MCP server for Oxygen Not Included seed hunting. Runs the sussy-seeds wasm scanner over stdio so an LLM can compose Builder AST specs and drive scans against onimaxxing worldgen.

Companion to the browser scanner at onimaxxing.com/sussy-seeds. Shared share-URL format round-trips between the MCP and the web app.

Install

Claude Code

.mcp.json (project) or ~/.claude/settings.json (user):

{
  "mcpServers": {
    "sussy-seeds": {
      "command": "npx",
      "args": ["-y", "@onimaxxing/sussy-seeds-mcp"]
    }
  }
}

Claude Desktop

~/Library/Application Support/Claude/claude_desktop_config.json on macOS, or the platform equivalent:

{
  "mcpServers": {
    "sussy-seeds": {
      "command": "npx",
      "args": ["-y", "@onimaxxing/sussy-seeds-mcp"]
    }
  }
}

Codex CLI

codex mcp add sussy-seeds -- npx -y @onimaxxing/sussy-seeds-mcp

Or edit ~/.codex/config.toml directly:

[mcp_servers.sussy-seeds]
command = "npx"
args = ["-y", "@onimaxxing/sussy-seeds-mcp"]

Other clients

Same {command, args} shape works in Cursor, Windsurf, Zed, Continue, Cline. Progress notifications carry _meta.progressToken.

Requirements

Node 20 or newer.

Tools

Discovery

• listClusters({filter?})
• listWorlds({coord}), listWorldsAcrossClusters({query})
• listStoryTraits, listMixingCategories
• listGeysers, listTraits, listBiomes, listPois
• listSpawnTags({query?, group?, offset?, limit?})
• listConstraintKinds
• listHelpers
• listPrefabAdmissibility({coord, prefabId})

Coord composition

• buildCoord({formState})
• parseCoord({coord})
• describeCoord({coord})
• freshCoord({clusterPrefix})

Admissibility

• verdictOf({coord, constraint}), verdictOfSpec({coord, spec})

Scanning

Streams notifications/progress when the client sends _meta.progressToken. Cancellable via JSON-RPC.

• scan({coord, spec, opts?}): top-K over a seed range. Bytecode tier (~1M/s/core) for require-only summary specs; JS tier otherwise.
• scanUntil({coord, spec, targetHits, opts?}): stops at N matches.
• scanSeeds({coord, spec, seeds}): one row per input seed.

spec.preHook and spec.postHook accept raw JS. Reserved-identifier guard rejects sources that shadow the Builder emit's bindings.

Inspection

• getSeedSummary({coord, seed})
• getSeedDeep({coord, seed})
• describeSeed({coord, seed, deep?})

Sharing

• shareResults({coord, spec, seeds, scanLimit?, tab?}): returns https://onimaxxing.com/sussy-seeds/<hash>. Opening the URL loads the spec, pins the seeds, sets the coord.

Diagnostics

• ping()
• probeStreaming({steps, delayMs})

Constraint kinds

world.trait, world.geyser, world.distToHome, world.distTo, world.traitCount, world.oilWells, world.critter, world.plant, world.spawn, world.biomeCount, world.marshyTungstenInMagma, world.niobiumVolcanoAccess, world.sussy, world.trash, world.asteroidRemix, poi.count, map.elementMass, home.geyserNearStart, cluster.geyser, cluster.oilWells, cluster.critter, cluster.plant, cluster.sussy, cluster.trash.

License

MIT.