feat: add custom/other OpenAI-compatible LLM providers

Allow Settings → Providers to define custom providers (id, name, base URL,
API key, models, headers) without code changes. Persist config via OpenCode
layers, store keys through auth.set, and keep web/VS Code parity.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/vscode/src/DOCUMENTATION.md

@@ -61,6 +61,7 @@ The webview CSP permits `blob:` only for `worker-src` so shared UI parsers can r
   - Includes session activity snapshot bridge handler used by webview parity routes (`/api/session-activity`).
   - Includes Zen utility model parity handler used by shared notification settings (`/api/zen/models`).
   - Owns managed OpenCode upgrade status and mutation handlers, including capability reporting, upgrade serialization, and process restart after a successful upgrade.
+  - Provider handlers cover source lookup, disconnect (`DELETE /api/provider/:id/auth`), and custom provider upsert (`PUT /api/provider`).
 
 - `opencode-upgrade-runtime.ts`
   - Owns managed-versus-external capability decisions, latest-version checks, serialized OpenCode self-upgrades, and restart-after-upgrade behavior.

packages/vscode/src/bridge-system-runtime.ts

@@ -3,7 +3,7 @@ import * as os from 'os';
 import * as path from 'path';
 import * as vscode from 'vscode';
 import { randomUUID } from 'crypto';
-import { removeProviderConfig, getProviderSources } from './opencodeConfig';
+import { removeProviderConfig, getProviderSources, upsertProviderConfig } from './opencodeConfig';
 import { getProviderAuth, removeProviderAuth } from './opencodeAuth';
 import { fetchQuotaForProvider, listConfiguredQuotaProviders } from './quotaProviders';
 import { fetchOpenCodeGoUsage } from './opencodeGoQuota';
@@ -485,6 +485,63 @@ export async function handleSystemBridgeMessage(
       }
     }
 
+    case 'api:provider:upsert': {
+      const {
+        providerID,
+        providerId: providerIdAlias,
+        config,
+        scope,
+        directory,
+      } = (payload || {}) as {
+        providerID?: string;
+        providerId?: string;
+        config?: unknown;
+        scope?: string;
+        directory?: string;
+      };
+      const providerId = (typeof providerID === 'string' && providerID.trim())
+        || (typeof providerIdAlias === 'string' && providerIdAlias.trim())
+        || '';
+      if (!providerId) {
+        return { id, type, success: false, error: 'Provider ID is required' };
+      }
+      if (!config || typeof config !== 'object' || Array.isArray(config)) {
+        return { id, type, success: false, error: 'Provider config is required' };
+      }
+      const normalizedScope = typeof scope === 'string' ? scope : 'user';
+      if (normalizedScope !== 'user' && normalizedScope !== 'project' && normalizedScope !== 'custom') {
+        return { id, type, success: false, error: 'Invalid scope' };
+      }
+      try {
+        const workingDirectory = typeof directory === 'string' && directory.trim().length > 0
+          ? directory.trim()
+          : ctx?.manager?.getWorkingDirectory();
+        const result = upsertProviderConfig(
+          providerId,
+          config,
+          workingDirectory,
+          normalizedScope,
+        );
+        await ctx?.manager?.restart();
+        return {
+          id,
+          type,
+          success: true,
+          data: {
+            success: true,
+            providerId: result.providerId,
+            path: result.path,
+            config: result.config,
+            requiresReload: true,
+            reloadDelayMs: deps.clientReloadDelayMs,
+          },
+        };
+      } catch (error) {
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        return { id, type, success: false, error: errorMessage };
+      }
+    }
+
     case 'api:quota:providers': {
       try {
         const providers = listConfiguredQuotaProviders();

packages/vscode/src/opencodeConfig.ts

@@ -2168,6 +2168,153 @@ export const removeProviderConfig = (providerId: string, workingDirectory?: stri
   return true;
 };
 
+const PROVIDER_ID_PATTERN = /^[a-z0-9][a-z0-9-_]*$/;
+const BASE_URL_PATTERN = /^https?:\/\//;
+const OPENAI_COMPATIBLE_NPM = '@ai-sdk/openai-compatible';
+
+export const validateCustomProviderConfig = (providerId: string, config: unknown) => {
+  if (!providerId || typeof providerId !== 'string' || !PROVIDER_ID_PATTERN.test(providerId)) {
+    return { ok: false as const, error: 'Provider ID must match /^[a-z0-9][a-z0-9-_]*$/' };
+  }
+
+  if (!isPlainObject(config)) {
+    return { ok: false as const, error: 'Provider config must be an object' };
+  }
+
+  const name = typeof config.name === 'string' ? config.name.trim() : '';
+  if (!name) {
+    return { ok: false as const, error: 'Provider name is required' };
+  }
+
+  const npm = typeof config.npm === 'string' ? config.npm.trim() : OPENAI_COMPATIBLE_NPM;
+  if (npm !== OPENAI_COMPATIBLE_NPM) {
+    return { ok: false as const, error: `Custom providers must use npm package ${OPENAI_COMPATIBLE_NPM}` };
+  }
+
+  const options = isPlainObject(config.options) ? config.options : null;
+  if (!options) {
+    return { ok: false as const, error: 'Provider options are required' };
+  }
+
+  const baseURL = typeof options.baseURL === 'string' ? options.baseURL.trim() : '';
+  if (!baseURL) {
+    return { ok: false as const, error: 'Base URL is required' };
+  }
+  if (!BASE_URL_PATTERN.test(baseURL)) {
+    return { ok: false as const, error: 'Base URL must start with http:// or https://' };
+  }
+
+  const models = isPlainObject(config.models) ? config.models : null;
+  if (!models || Object.keys(models).length === 0) {
+    return { ok: false as const, error: 'At least one model is required' };
+  }
+
+  const normalizedModels: Record<string, { name: string }> = {};
+  for (const [modelId, modelValue] of Object.entries(models)) {
+    const trimmedId = typeof modelId === 'string' ? modelId.trim() : '';
+    if (!trimmedId) {
+      return { ok: false as const, error: 'Model id is required' };
+    }
+    if (!isPlainObject(modelValue)) {
+      return { ok: false as const, error: `Model "${trimmedId}" must be an object` };
+    }
+    const modelName = typeof modelValue.name === 'string' ? modelValue.name.trim() : '';
+    if (!modelName) {
+      return { ok: false as const, error: `Model "${trimmedId}" requires a name` };
+    }
+    normalizedModels[trimmedId] = { name: modelName };
+  }
+
+  const normalized: Record<string, unknown> = {
+    npm: OPENAI_COMPATIBLE_NPM,
+    name,
+    options: {
+      baseURL,
+    },
+    models: normalizedModels,
+  };
+
+  if (Array.isArray(config.env)) {
+    const env = config.env
+      .filter((entry): entry is string => typeof entry === 'string' && entry.trim().length > 0)
+      .map((entry) => entry.trim());
+    if (env.length > 0) {
+      normalized.env = env;
+    }
+  }
+
+  if (isPlainObject(options.headers)) {
+    const headers: Record<string, string> = {};
+    for (const [headerKey, headerValue] of Object.entries(options.headers)) {
+      if (typeof headerKey !== 'string' || !headerKey.trim()) {
+        continue;
+      }
+      if (typeof headerValue !== 'string' || !headerValue.trim()) {
+        return { ok: false as const, error: `Header "${headerKey}" requires a non-empty value` };
+      }
+      headers[headerKey.trim()] = headerValue.trim();
+    }
+    if (Object.keys(headers).length > 0) {
+      (normalized.options as Record<string, unknown>).headers = headers;
+    }
+  }
+
+  return { ok: true as const, value: { providerId, config: normalized } };
+};
+
+export const upsertProviderConfig = (
+  providerId: string,
+  config: unknown,
+  workingDirectory?: string,
+  scope: 'user' | 'project' | 'custom' = 'user',
+) => {
+  const validated = validateCustomProviderConfig(providerId, config);
+  if (!validated.ok) {
+    const error = new Error(validated.error) as Error & { statusCode?: number };
+    error.statusCode = 400;
+    throw error;
+  }
+
+  const layers = readConfigLayers(workingDirectory);
+  let targetPath: string | null | undefined = layers.paths.userPath;
+
+  if (scope === 'project') {
+    if (!workingDirectory) {
+      throw new Error('Working directory is required for project scope');
+    }
+    targetPath = layers.paths.projectPath ?? targetPath;
+  } else if (scope === 'custom') {
+    if (!layers.paths.customPath) {
+      throw new Error('Custom config path (OPENCODE_CONFIG) is not set');
+    }
+    targetPath = layers.paths.customPath;
+  } else if (scope !== 'user') {
+    throw new Error('Invalid scope');
+  }
+
+  const targetConfig = getConfigForPath(layers, targetPath) as Record<string, unknown>;
+  const providerConfig = isPlainObject(targetConfig.provider)
+    ? { ...(targetConfig.provider as Record<string, unknown>) }
+    : {};
+  providerConfig[validated.value.providerId] = validated.value.config;
+  targetConfig.provider = providerConfig;
+
+  if (Array.isArray(targetConfig.disabled_providers)) {
+    targetConfig.disabled_providers = targetConfig.disabled_providers.filter(
+      (entry) => entry !== validated.value.providerId,
+    );
+  }
+
+  const writePath = targetPath || CONFIG_FILE;
+  writeConfig(targetConfig, writePath);
+
+  return {
+    providerId: validated.value.providerId,
+    path: writePath,
+    config: validated.value.config,
+  };
+};
+
 export const deleteCommand = (commandName: string, workingDirectory?: string) => {
   let deleted = false;