feat(providers): OpenRouter adapter + Ollama embedding support — M3-004/006 (#311)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/agent/adapters/openrouter.adapter.ts

@@ -0,0 +1,212 @@
+import { Logger } from '@nestjs/common';
+import OpenAI from 'openai';
+import type {
+  CompletionEvent,
+  CompletionParams,
+  IProviderAdapter,
+  ModelInfo,
+  ProviderHealth,
+} from '@mosaic/types';
+
+const OPENROUTER_BASE_URL = 'https://openrouter.ai/api/v1';
+
+interface OpenRouterModel {
+  id: string;
+  name?: string;
+  context_length?: number;
+  top_provider?: {
+    max_completion_tokens?: number;
+  };
+  pricing?: {
+    prompt?: string | number;
+    completion?: string | number;
+  };
+  architecture?: {
+    input_modalities?: string[];
+  };
+}
+
+interface OpenRouterModelsResponse {
+  data?: OpenRouterModel[];
+}
+
+/**
+ * OpenRouter provider adapter.
+ *
+ * Routes completions through OpenRouter's OpenAI-compatible API.
+ * Configuration is driven by the OPENROUTER_API_KEY environment variable.
+ */
+export class OpenRouterAdapter implements IProviderAdapter {
+  readonly name = 'openrouter';
+
+  private readonly logger = new Logger(OpenRouterAdapter.name);
+  private client: OpenAI | null = null;
+  private registeredModels: ModelInfo[] = [];
+
+  async register(): Promise<void> {
+    const apiKey = process.env['OPENROUTER_API_KEY'];
+    if (!apiKey) {
+      this.logger.debug('Skipping OpenRouter provider registration: OPENROUTER_API_KEY not set');
+      return;
+    }
+
+    this.client = new OpenAI({
+      apiKey,
+      baseURL: OPENROUTER_BASE_URL,
+      defaultHeaders: {
+        'HTTP-Referer': 'https://mosaic.ai',
+        'X-Title': 'Mosaic',
+      },
+    });
+
+    try {
+      this.registeredModels = await this.fetchModels(apiKey);
+      this.logger.log(`OpenRouter provider registered with ${this.registeredModels.length} models`);
+    } catch (err) {
+      this.logger.warn(
+        `OpenRouter model discovery failed: ${err instanceof Error ? err.message : String(err)}. Registering with empty model list.`,
+      );
+      this.registeredModels = [];
+    }
+  }
+
+  listModels(): ModelInfo[] {
+    return this.registeredModels;
+  }
+
+  async healthCheck(): Promise<ProviderHealth> {
+    const apiKey = process.env['OPENROUTER_API_KEY'];
+    if (!apiKey) {
+      return {
+        status: 'down',
+        lastChecked: new Date().toISOString(),
+        error: 'OPENROUTER_API_KEY not configured',
+      };
+    }
+
+    const start = Date.now();
+    try {
+      const res = await fetch(`${OPENROUTER_BASE_URL}/models`, {
+        method: 'GET',
+        headers: {
+          Authorization: `Bearer ${apiKey}`,
+          Accept: 'application/json',
+        },
+        signal: AbortSignal.timeout(5000),
+      });
+      const latencyMs = Date.now() - start;
+
+      if (!res.ok) {
+        return {
+          status: 'degraded',
+          latencyMs,
+          lastChecked: new Date().toISOString(),
+          error: `HTTP ${res.status}`,
+        };
+      }
+
+      return { status: 'healthy', latencyMs, lastChecked: new Date().toISOString() };
+    } catch (err) {
+      const latencyMs = Date.now() - start;
+      const error = err instanceof Error ? err.message : String(err);
+      return { status: 'down', latencyMs, lastChecked: new Date().toISOString(), error };
+    }
+  }
+
+  /**
+   * Stream a completion through OpenRouter's OpenAI-compatible API.
+   */
+  async *createCompletion(params: CompletionParams): AsyncIterable<CompletionEvent> {
+    if (!this.client) {
+      throw new Error('OpenRouterAdapter is not initialized. Ensure OPENROUTER_API_KEY is set.');
+    }
+
+    const stream = await this.client.chat.completions.create({
+      model: params.model,
+      messages: params.messages.map((m) => ({ role: m.role, content: m.content })),
+      temperature: params.temperature,
+      max_tokens: params.maxTokens,
+      stream: true,
+    });
+
+    let inputTokens = 0;
+    let outputTokens = 0;
+
+    for await (const chunk of stream) {
+      const choice = chunk.choices[0];
+      if (!choice) continue;
+
+      const delta = choice.delta;
+
+      if (delta.content) {
+        yield { type: 'text_delta', content: delta.content };
+      }
+
+      if (choice.finish_reason === 'stop') {
+        const usage = (chunk as { usage?: { prompt_tokens?: number; completion_tokens?: number } })
+          .usage;
+        if (usage) {
+          inputTokens = usage.prompt_tokens ?? 0;
+          outputTokens = usage.completion_tokens ?? 0;
+        }
+      }
+    }
+
+    yield {
+      type: 'done',
+      usage: { inputTokens, outputTokens },
+    };
+  }
+
+  // ---------------------------------------------------------------------------
+  // Private helpers
+  // ---------------------------------------------------------------------------
+
+  private async fetchModels(apiKey: string): Promise<ModelInfo[]> {
+    const res = await fetch(`${OPENROUTER_BASE_URL}/models`, {
+      method: 'GET',
+      headers: {
+        Authorization: `Bearer ${apiKey}`,
+        Accept: 'application/json',
+      },
+      signal: AbortSignal.timeout(10000),
+    });
+
+    if (!res.ok) {
+      throw new Error(`OpenRouter models endpoint returned HTTP ${res.status}`);
+    }
+
+    const json = (await res.json()) as OpenRouterModelsResponse;
+    const data = json.data ?? [];
+
+    return data.map((model): ModelInfo => {
+      const inputPrice = model.pricing?.prompt
+        ? parseFloat(String(model.pricing.prompt)) * 1000
+        : 0;
+      const outputPrice = model.pricing?.completion
+        ? parseFloat(String(model.pricing.completion)) * 1000
+        : 0;
+
+      const inputModalities = model.architecture?.input_modalities ?? ['text'];
+      const inputTypes = inputModalities.includes('image')
+        ? (['text', 'image'] as const)
+        : (['text'] as const);
+
+      return {
+        id: model.id,
+        provider: 'openrouter',
+        name: model.name ?? model.id,
+        reasoning: false,
+        contextWindow: model.context_length ?? 4096,
+        maxTokens: model.top_provider?.max_completion_tokens ?? 4096,
+        inputTypes: [...inputTypes],
+        cost: {
+          input: inputPrice,
+          output: outputPrice,
+          cacheRead: 0,
+          cacheWrite: 0,
+        },
+      };
+    });
+  }
+}