feat: introduce provider abstraction for multi-LLM support (Closes #25)

src/agents/orchestrator.js

@@ -1,5 +1,9 @@
 import { config } from '../config.js'
 import { AGENTS, getAgentById } from './registry.js'
+import { getProvider, listProviders } from '../providers/index.js'
+
+// Legacy imports — kept for backward compatibility
+// New code should use getProvider() from the provider layer
 import {
   runResearch,
   runSummary,

src/config.js

@@ -49,6 +49,10 @@ export const config = {
     100,
     toNumberOr(process.env.ANTHROPIC_RETRY_BASE_DELAY_MS, 500)
   ),
+
+  // Provider abstraction for multi-LLM support
+  provider: (process.env.PROVIDER || 'anthropic').toLowerCase(),
+
   logFormat: (process.env.LOG_FORMAT || 'json').toLowerCase() === 'pretty' ? 'pretty' : 'json',
   // Rate limiting (defaults are intentionally permissive for demos)
   rateLimit: {

src/providers/anthropic-provider.js

@@ -0,0 +1,36 @@
+/**
+ * Anthropic Provider — default implementation. Behavior unchanged from services.js.
+ */
+import Anthropic from '@anthropic-ai/sdk'
+import { config } from '../config.js'
+
+export const name = 'anthropic'
+// eslint-disable-next-line no-unused-vars
+const _anthropicClient = new Anthropic({ apiKey: config.anthropicApiKey })
+let available = true
+
+export const capabilities = {
+  research: { model: 'claude-haiku-4-5-20251001', label: 'Claude Haiku 4.5' },
+  summary: { model: 'claude-haiku-4-5-20251001', label: 'Claude Haiku 4.5' },
+  analysis: { model: 'claude-sonnet-4-5-20250929', fallback: 'claude-haiku-4-5-20251001', label: 'Claude Sonnet 4.5' },
+  code: { model: 'claude-haiku-4-5-20251001', label: 'Claude Haiku 4.5' },
+}
+
+export function setApiKey(newKey) {
+  _anthropicClient = new Anthropic({ apiKey: newKey })
+  config.anthropicApiKey = newKey
+  available = true
+}
+
+export const isAvailable = () => available
+
+import { runResearch, runSummary, runAnalysis, runCode, createAnthropicMessage } from '../agents/services.js'
+export const research = runResearch
+export const summary = runSummary
+export const analysis = runAnalysis
+export const code = runCode
+export const createMessage = createAnthropicMessage
+
+export function getProvider() {
+  return { name, capabilities, research, summary, analysis, code, createMessage, setApiKey, isAvailable }
+}

src/providers/index.js

@@ -0,0 +1,45 @@
+/**
+ * Provider Factory — selects and caches the configured LLM provider.
+ * Usage: import { getProvider } from './providers/index.js'
+ */
+import { config } from '../config.js'
+import { validateProvider } from './interface.js'
+import { getProvider as getAnthropic } from './anthropic-provider.js'
+import { getProvider as getOpenAI } from './openai-provider.js'
+
+const REGISTRY = { anthropic: getAnthropic, openai: getOpenAI }
+const NAMES = Object.keys(REGISTRY)
+let _cached = null
+
+export function getProvider() {
+  if (_cached) return _cached
+  const name = (config.provider || 'anthropic').toLowerCase()
+  if (!REGISTRY[name]) {
+    console.warn(`[provider] Unknown "${name}", using anthropic. Available: ${NAMES.join(', ')}`)
+    _cached = REGISTRY.anthropic()
+    return _cached
+  }
+  _cached = REGISTRY[name]()
+  const v = validateProvider(_cached)
+  if (!v.valid) {
+    console.error(`[provider] "${name}" incomplete: ${v.missing.join(', ')}. Using anthropic.`)
+    _cached = REGISTRY.anthropic()
+  }
+  return _cached
+}
+
+export function listProviders() {
+  return NAMES.map((n) => {
+    const p = REGISTRY[n]()
+    return {
+      name: n,
+      available: p.isAvailable ? p.isAvailable() : true,
+      capabilities: p.capabilities,
+    }
+  })
+}
+
+export function resetProvider() {
+  _cached = null
+}
+export { validateProvider, PROVIDER_MODES } from './interface.js'

src/providers/interface.js

@@ -0,0 +1,10 @@
+/**
+ * Provider Interface — contract for LLM provider implementations.
+ * Required: name, capabilities, research(), summary(), analysis(), code()
+ */
+export function validateProvider(provider) {
+  const required = ['name', 'research', 'summary', 'analysis', 'code', 'capabilities']
+  const missing = required.filter((key) => typeof provider[key] === 'undefined')
+  return { valid: missing.length === 0, missing }
+}
+export const PROVIDER_MODES = ['research', 'summary', 'analysis', 'code']

src/providers/openai-provider.js

@@ -0,0 +1,26 @@
+/**
+ * OpenAI Provider — PLACEHOLDER. Set PROVIDER=openai to activate when implemented.
+ */
+export const name = 'openai'
+export const capabilities = {
+  research: { model: 'gpt-4o-mini', label: 'GPT-4o Mini' },
+  summary: { model: 'gpt-4o-mini', label: 'GPT-4o Mini' },
+  analysis: { model: 'gpt-4o', fallback: 'gpt-4o-mini', label: 'GPT-4o' },
+  code: { model: 'gpt-4o-mini', label: 'GPT-4o Mini' },
+}
+function notYet(mode) {
+  return async () => {
+    throw new Error(
+      `OpenAI ${mode} not implemented. Use PROVIDER=anthropic.`
+    )
+  }
+}
+export const research = notYet('research')
+export const summary = notYet('summary')
+export const analysis = notYet('analysis')
+export const code = notYet('code')
+export const isAvailable = () => false
+export function setApiKey(_k) {}
+export function getProvider() {
+  return { name, capabilities, research, summary, analysis, code, setApiKey, isAvailable }
+}