Custom providers

Need to point Loom at something that isn't Claude Code, Ollama, or an OpenAI-compatible server? You have two options today: add it as an OpenAI-compatible endpoint (often works) or write a new LLMProvider in code.

Try OpenAI-compatible first

A surprising number of "weird" LLM servers actually speak the OpenAI wire format. If your server has any of these in its docs, add it as OpenAI-compatible in Settings → Providers:

• "OpenAI-compatible API"
• "OpenAI proxy"
• A POST /v1/chat/completions endpoint
• A POST /chat/completions endpoint (set Base URL to the parent — Loom appends /chat/completions)

This covers: vLLM, LocalAI, OpenRouter (with their key), Together, Groq, Mistral's chat endpoint, Anyscale, Perplexity, Fireworks, DeepInfra, and dozens more.

Adding a new provider in code

If your target speaks a non-OpenAI wire format, drop a file into Loom/Agents/ that conforms to LLMProvider:

// Loom/Agents/MyCoolProvider.swift
import Foundation

struct MyCoolProvider: LLMProvider {
    let baseURL: URL
    let model: String
    var displayName: String { "MyCool · \(model)" }

    func stream(
        messages: [LLMMessage],
        system: String?
    ) -> AsyncThrowingStream<LLMEvent, Error> {
        AsyncThrowingStream { continuation in
            let task = Task {
                do {
                    // Build URLRequest, call URLSession.shared.bytes(for:),
                    // parse the wire format, yield .textDelta(...) per token.
                    continuation.yield(.done)
                    continuation.finish()
                } catch {
                    continuation.finish(throwing: error)
                }
            }
            continuation.onTermination = { _ in task.cancel() }
        }
    }
}

Then:

1. Add a vendor case to AgentDescriptor.Vendor in Loom/Agents/AgentRegistry.swift (mark it isLocalHTTP if it's HTTP-streamed).
2. Surface the provider in the registry — either by registering it from a LocalEndpoint kind or adding a hardcoded descriptor.
3. Wire it into AgentPaneView.sendViaLocalHTTP (or write a parallel send method if it has unique requirements).
4. Run xcodegen generate to regenerate the project after adding the file.

See OllamaProvider.swift and OpenAICompatibleProvider.swift for two complete reference implementations.

Why not a plugin system?

Loom is a personal tool. A plugin system has its own surface area (signing, sandboxing, distribution) that doesn't pay back for a single-user app. Editing the source and rebuilding is the supported extension path.