feat(opencode): add LiteLLM provider integration

packages/app/src/components/dialog-select-provider.tsx

@@ -24,6 +24,7 @@ export const DialogSelectProvider: Component = () => {
     if (id === "openai") return language.t("dialog.provider.openai.note")
     if (id.startsWith("github-copilot")) return language.t("dialog.provider.copilot.note")
     if (id === "opencode-go") return language.t("dialog.provider.opencodeGo.tagline")
+    if (id === "litellm") return language.t("dialog.provider.litellm.note")
   }
 
   return (

packages/app/src/components/settings-providers.tsx

@@ -26,6 +26,7 @@ const PROVIDER_NOTES = [
   { match: (id: string) => id === "google", key: "dialog.provider.google.note" },
   { match: (id: string) => id === "openrouter", key: "dialog.provider.openrouter.note" },
   { match: (id: string) => id === "vercel", key: "dialog.provider.vercel.note" },
+  { match: (id: string) => id === "litellm", key: "dialog.provider.litellm.note" },
 ] as const
 
 export const SettingsProviders: Component = () => {

packages/app/src/i18n/en.ts

@@ -110,6 +110,7 @@ export const dict = {
   "dialog.provider.google.note": "Gemini models for fast, structured responses",
   "dialog.provider.openrouter.note": "Access all supported models from one provider",
   "dialog.provider.vercel.note": "Unified access to AI models with smart routing",
+  "dialog.provider.litellm.note": "Unified proxy for 100+ LLMs with load balancing and spend tracking",
 
   "dialog.model.select.title": "Select model",
   "dialog.model.search.placeholder": "Search models",

packages/core/src/provider.ts

@@ -18,6 +18,7 @@ export const ID = Schema.String.pipe(
     openrouter: schema.make("openrouter"),
     mistral: schema.make("mistral"),
     gitlab: schema.make("gitlab"),
+    litellm: schema.make("litellm"),
   })),
 )
 export type ID = typeof ID.Type

packages/opencode/src/plugin/index.ts

@@ -13,6 +13,7 @@ import { CodexAuthPlugin } from "./openai/codex"
 import { Session } from "@/session/session"
 import { NamedError } from "@opencode-ai/core/util/error"
 import { CopilotAuthPlugin } from "./github-copilot/copilot"
+import { LiteLLMPlugin } from "./litellm/litellm"
 import { gitlabAuthPlugin as GitlabAuthPlugin } from "opencode-gitlab-auth"
 import { PoeAuthPlugin } from "opencode-poe-auth"
 import { CloudflareAIGatewayAuthPlugin, CloudflareWorkersAuthPlugin } from "./cloudflare"
@@ -71,6 +72,7 @@ function internalPlugins(flags: RuntimeFlags.Info): PluginInstance[] {
         experimentalWebSockets: experimentalWebSocketsEnabled({ enabled: flags.experimentalWebSockets }),
       }),
     CopilotAuthPlugin,
+    LiteLLMPlugin,
     GitlabAuthPlugin,
     PoeAuthPlugin,
     CloudflareWorkersAuthPlugin,

packages/opencode/src/plugin/litellm/litellm.ts

@@ -0,0 +1,66 @@
+import type { Hooks, PluginInput } from "@opencode-ai/plugin"
+import * as Log from "@opencode-ai/core/util/log"
+import { LiteLLMModels } from "./models"
+
+const log = Log.create({ service: "plugin.litellm" })
+
+export async function LiteLLMPlugin(input: PluginInput): Promise<Hooks> {
+  return {
+    provider: {
+      id: "litellm",
+      async models(provider, ctx) {
+        const baseURL = (() => {
+          if (provider.options?.baseURL) return provider.options.baseURL as string
+          if (process.env["LITELLM_BASE_URL"]) return process.env["LITELLM_BASE_URL"]
+          return undefined
+        })()
+
+        if (!baseURL) {
+          return provider.models
+        }
+
+        const headers: Record<string, string> = {}
+        if (ctx.auth?.type === "api" && ctx.auth.key) {
+          headers["Authorization"] = `Bearer ${ctx.auth.key}`
+        } else if (process.env["LITELLM_API_KEY"]) {
+          headers["Authorization"] = `Bearer ${process.env["LITELLM_API_KEY"]}`
+        }
+
+        return LiteLLMModels.get(baseURL, headers, provider.models).catch((error) => {
+          log.error("failed to fetch litellm models", { error })
+          return provider.models
+        })
+      },
+    },
+    auth: {
+      provider: "litellm",
+      async loader(getAuth) {
+        const auth = await getAuth()
+        if (auth.type !== "api") {
+          // Fall back to env var
+          const envKey = process.env["LITELLM_API_KEY"]
+          if (envKey) return { apiKey: envKey }
+          return {}
+        }
+
+        return {
+          apiKey: auth.key,
+        }
+      },
+      methods: [
+        {
+          label: "Enter LiteLLM API Key",
+          type: "api",
+          prompts: [
+            {
+              type: "text",
+              key: "base_url",
+              message: "LiteLLM proxy base URL (e.g. http://localhost:4000)",
+              placeholder: "http://localhost:4000",
+            },
+          ],
+        },
+      ],
+    },
+  }
+}

packages/opencode/src/plugin/litellm/models.ts

@@ -0,0 +1,133 @@
+import type { Model } from "@opencode-ai/sdk/v2"
+import { InstallationVersion } from "@opencode-ai/core/installation/version"
+import * as Log from "@opencode-ai/core/util/log"
+import os from "os"
+
+const log = Log.create({ service: "plugin.litellm.models" })
+
+interface LiteLLMModelEntry {
+  id: string
+  created?: number
+  owned_by?: string
+}
+
+interface LiteLLMModelInfo {
+  max_tokens?: number
+  max_input_tokens?: number
+  max_output_tokens?: number
+  input_cost_per_token?: number
+  output_cost_per_token?: number
+  supports_vision?: boolean
+  supports_function_calling?: boolean
+  mode?: string
+}
+
+async function fetchModelInfo(
+  baseURL: string,
+  headers: Record<string, string>,
+): Promise<Record<string, LiteLLMModelInfo>> {
+  try {
+    const url = `${baseURL.replace(/\/+$/, "")}/model/info`
+    const res = await fetch(url, {
+      headers,
+      signal: AbortSignal.timeout(5_000),
+    })
+    if (!res.ok) return {}
+    const body = (await res.json()) as { data?: Array<{ model_name: string; model_info?: LiteLLMModelInfo }> }
+    if (!Array.isArray(body.data)) return {}
+    const info: Record<string, LiteLLMModelInfo> = {}
+    for (const entry of body.data) {
+      if (entry.model_name && entry.model_info) {
+        info[entry.model_name] = entry.model_info
+      }
+    }
+    return info
+  } catch {
+    return {}
+  }
+}
+
+function buildModel(id: string, baseURL: string, info?: LiteLLMModelInfo, prev?: Model): Model {
+  const maxContext = info?.max_tokens ?? info?.max_input_tokens ?? 128_000
+  const maxOutput = info?.max_output_tokens ?? 16_384
+
+  const inputCost = info?.input_cost_per_token ?? 0
+  const outputCost = info?.output_cost_per_token ?? 0
+
+  return {
+    id: id,
+    providerID: "litellm",
+    name: prev?.name ?? id,
+    api: {
+      id,
+      url: baseURL,
+      npm: "@ai-sdk/openai-compatible",
+    },
+    status: "active",
+    headers: prev?.headers ?? {},
+    options: prev?.options ?? {},
+    cost: {
+      input: inputCost * 1_000_000,
+      output: outputCost * 1_000_000,
+      cache: { read: 0, write: 0 },
+    },
+    limit: {
+      context: maxContext,
+      output: maxOutput,
+    },
+    capabilities: {
+      temperature: true,
+      reasoning: prev?.capabilities?.reasoning ?? false,
+      attachment: true,
+      toolcall: info?.supports_function_calling ?? prev?.capabilities?.toolcall ?? true,
+      input: {
+        text: true,
+        audio: false,
+        image: info?.supports_vision ?? prev?.capabilities?.input?.image ?? true,
+        video: false,
+        pdf: false,
+      },
+      output: { text: true, audio: false, image: false, video: false, pdf: false },
+      interleaved: false,
+    },
+    release_date: prev?.release_date ?? "",
+    variants: prev?.variants ?? {},
+  }
+}
+
+export async function get(
+  baseURL: string,
+  headers: Record<string, string> = {},
+  existing: Record<string, Model> = {},
+): Promise<Record<string, Model>> {
+  const modelsURL = `${baseURL.replace(/\/+$/, "")}/v1/models`
+  const reqHeaders: Record<string, string> = {
+    "User-Agent": `opencode/${InstallationVersion} litellm (${os.platform()} ${os.release()}; ${os.arch()})`,
+    ...headers,
+  }
+
+  const res = await fetch(modelsURL, {
+    headers: reqHeaders,
+    signal: AbortSignal.timeout(5_000),
+  })
+  if (!res.ok) throw new Error(`Failed to fetch models: ${res.status}`)
+
+  const body = (await res.json()) as { data?: LiteLLMModelEntry[] }
+  if (!Array.isArray(body.data)) return existing
+
+  // Enrich with per-model metadata from /model/info
+  const modelInfo = await fetchModelInfo(baseURL, reqHeaders)
+
+  const result = { ...existing }
+
+  for (const entry of body.data) {
+    const id = entry.id
+    if (!id) continue
+    const info = modelInfo[id]
+    result[id] = buildModel(id, baseURL, info, existing[id])
+  }
+
+  return result
+}
+
+export * as LiteLLMModels from "./models"

packages/opencode/src/provider/provider.ts

@@ -1127,7 +1127,7 @@ export function fromModelsDevProvider(provider: ModelsDev.Provider): Info {
       const base = fromModelsDevModel(provider, model)
       models[id] = {
         ...base,
-        id: ProviderV2.ModelID.make(id),
+        id: ProviderV2.ProviderV2.ModelID.make(id),
         name: `${model.name} ${mode[0].toUpperCase()}${mode.slice(1)}`,
         cost: opts.cost ? mergeDeep(base.cost, cost(opts.cost)) : base.cost,
         options: opts.provider?.body
@@ -1257,6 +1257,17 @@ export const layer = Layer.effect(
           const providerID = ProviderV2.ID.make(p.id)
           if (disabled.has(providerID)) continue
 
+          // Seed provider entry if the plugin declares one but it's not in models.dev or config
+          if (!database[providerID]) {
+            database[providerID] = {
+              id: providerID,
+              name: providerID,
+              source: "env",
+              env: [],
+              options: {},
+              models: {},
+            }
+          }
           const provider = database[providerID]
           if (!provider) continue
           const pluginAuth = yield* auth.get(providerID).pipe(Effect.orDie)
@@ -1268,12 +1279,17 @@ export const layer = Layer.effect(
                 id,
                 {
                   ...model,
-                  id: ProviderV2.ModelID.make(id),
+                  id: ProviderV2.ProviderV2.ModelID.make(id),
                   providerID,
                 },
               ]),
             )
           })
+
+          // Ensure plugin-seeded providers appear in the state
+          if (!providers[providerID]) {
+            mergeProvider(providerID, { source: "env" })
+          }
         }
 
         // extend database from config

packages/ui/src/components/provider-icons/types.ts

@@ -33,6 +33,7 @@ export const iconNames = [
   "ovhcloud",
   "openrouter",
   "llmgateway",
+  "litellm",
   "opencode",
   "opencode-go",
   "openai",