{"passport":{"unfragile":{"@version":"1.0","version":"2026-05","artifact":{"id":"awesome-nexus","slug":"nexus","name":"Nexus","type":"repo","url":"https://github.com/adawalli/nexus","page_url":"https://unfragile.ai/nexus","categories":["automation"],"tags":[],"pricing":{"model":"open_source","free":true,"starting_price":null},"status":"active","verified":false},"capabilities":[{"id":"awesome-nexus__cap_0","uri":"capability://search.retrieval.mcp.native.web.search.with.perplexity.sonar.models","name":"mcp-native web search with perplexity sonar models","description":"Exposes real-time web search as an MCP tool that AI assistants can invoke directly via the Model Context Protocol. Implements the SearchTool class which routes queries to OpenRouter's Perplexity Sonar endpoints (sonar, sonar-pro, sonar-reasoning-pro, sonar-deep-research), handling model selection, request marshaling, and response parsing within the MCP protocol contract. Uses STDIO transport for bidirectional communication with MCP clients like Claude Desktop and Cursor.","intents":["Enable Claude or Cursor to perform real-time web searches without leaving the IDE or chat interface","Give AI assistants access to current information beyond their training cutoff","Integrate web search as a native tool in agentic workflows without custom API wrappers"],"best_for":["AI developers building Claude Desktop or Cursor extensions","Teams using Claude as an agent that needs real-time information access","Builders integrating MCP servers into LLM applications"],"limitations":["Requires OpenRouter API key with Perplexity Sonar access — not free tier compatible","STDIO transport limits to single-threaded request handling per server instance","Model selection is static per server invocation — cannot switch models mid-session without restart","Response latency depends on OpenRouter backend availability and model inference time (typically 2-8 seconds)"],"requires":["Node.js 18+","OpenRouter API key with Perplexity Sonar model access","MCP-compatible client (Claude Desktop, Cursor, or custom MCP client)","OPENROUTER_API_KEY environment variable configured"],"input_types":["text query string","model selection parameter (sonar | sonar-pro | sonar-reasoning-pro | sonar-deep-research | grok-4)"],"output_types":["structured JSON with search results","citation metadata with source URLs","reasoning traces (for reasoning-pro model)"],"categories":["search-retrieval","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_1","uri":"capability://data.processing.analysis.request.deduplication.with.ttl.based.caching","name":"request deduplication with ttl-based caching","description":"Implements RequestDeduplicator and TTLCache utilities to prevent duplicate concurrent requests and cache results for configurable time windows. When multiple identical queries arrive within the TTL window, the system returns the cached response instead of making redundant OpenRouter API calls, reducing latency and API costs. Deduplication is request-level (same query string) and operates transparently within the search pipeline.","intents":["Reduce API costs by avoiding duplicate searches when the same query is issued multiple times","Improve response latency for repeated queries by serving cached results","Handle concurrent identical requests from multiple MCP clients without thundering herd"],"best_for":["Teams running shared Nexus servers serving multiple AI assistants","Cost-conscious deployments where OpenRouter API spend is a concern","High-concurrency scenarios with repeated query patterns"],"limitations":["TTL is global and configurable only via environment variable — no per-query TTL control","Cache is in-memory only — lost on server restart, no persistence layer","Deduplication window is request-level only — semantic similarity is not detected (e.g., 'weather in NYC' and 'NYC weather' are treated as different queries)","No cache invalidation mechanism — stale results may be served until TTL expires"],"requires":["TTL_CACHE_DURATION environment variable (default likely 300-600 seconds, exact value from config)","Concurrent request handling enabled in MCP server"],"input_types":["query string (exact match required for deduplication)"],"output_types":["cached search result JSON","cache hit/miss metadata"],"categories":["data-processing-analysis","automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_10","uri":"capability://automation.workflow.zero.install.deployment.via.npx.with.automatic.dependency.resolution","name":"zero-install deployment via npx with automatic dependency resolution","description":"Packages Nexus as an npm module that can be executed directly via npx nexus-mcp without requiring npm install or global installation. npx automatically downloads the latest version, resolves dependencies, and runs the CLI entry point. Requires only Node.js 18+ and an OpenRouter API key in the environment.","intents":["Enable users to start using Nexus with a single command without setup friction","Support ephemeral deployments (e.g., CI/CD, containers) where persistent installation is unnecessary","Reduce onboarding time for Claude Desktop and Cursor users"],"best_for":["Individual developers testing Nexus locally","Non-technical users who want to add search to Claude Desktop","CI/CD pipelines that need temporary search capability"],"limitations":["First run downloads the package — adds 5-10 second startup latency","No offline mode — requires internet access to download from npm registry","Version pinning is not automatic — npx always fetches latest unless @version specified","Dependency conflicts may occur if system has incompatible Node.js or npm versions"],"requires":["Node.js 18+ installed","npm 5.2+ (comes with Node.js)","Internet access to npm registry","OPENROUTER_API_KEY environment variable"],"input_types":["npx command with optional arguments (npx nexus-mcp --model sonar-pro)"],"output_types":["running MCP server ready to accept connections"],"categories":["automation-workflow","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_11","uri":"capability://automation.workflow.concurrent.request.handling.with.deduplication.and.coalescing","name":"concurrent request handling with deduplication and coalescing","description":"Implements request deduplication at the MCP server level to handle multiple concurrent identical queries. When multiple MCP clients send the same search query simultaneously, the system coalesces them into a single OpenRouter API call and broadcasts the result to all waiting clients. Uses RequestDeduplicator to track in-flight requests and coordinate responses.","intents":["Reduce API costs when multiple Claude instances or users search for the same thing simultaneously","Improve latency for concurrent identical queries by serving a single cached result","Handle thundering herd scenarios where many clients request the same information"],"best_for":["Shared Nexus servers serving multiple Claude Desktop instances or users","High-concurrency environments where duplicate queries are likely","Cost-sensitive deployments where API call reduction is critical"],"limitations":["Deduplication is exact-match only — semantic similarity is not detected","Coalescing window is limited to in-flight requests — not persistent across server restarts","No priority queue — all concurrent requests are treated equally","Response broadcast may have latency skew — first client gets result slightly before others"],"requires":["RequestDeduplicator utility enabled in search pipeline","Concurrent request handling in MCP server core"],"input_types":["multiple JSON-RPC search requests with identical query parameters"],"output_types":["single OpenRouter API call, with result broadcast to all waiting clients"],"categories":["automation-workflow","data-processing-analysis"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_2","uri":"capability://safety.moderation.structured.error.handling.with.typed.exception.hierarchy.and.exponential.backoff","name":"structured error handling with typed exception hierarchy and exponential backoff","description":"Implements BaseError hierarchy with typed exception classes (e.g., ValidationError, APIError, TimeoutError) that provide context-aware error messages and automatic retry logic with exponential backoff. When transient failures occur (rate limits, temporary API outages), the system automatically retries with increasing delays (e.g., 1s, 2s, 4s, 8s) up to a configurable maximum. Errors are logged with structured metadata and propagated to MCP clients with actionable error codes.","intents":["Automatically recover from transient OpenRouter API failures without user intervention","Provide clear error messages to MCP clients distinguishing between user input errors and system failures","Reduce manual retry burden by implementing intelligent backoff strategies"],"best_for":["Production deployments where API reliability is critical","Teams building resilient agentic systems that must handle API failures gracefully","Developers debugging search failures with structured error context"],"limitations":["Exponential backoff is fixed algorithm — no jitter, which can cause thundering herd in distributed scenarios","Maximum retry attempts and backoff ceiling are likely hardcoded — not configurable per request","Retry logic only applies to transient errors (5xx, rate limits) — permanent errors (4xx validation) fail immediately","No circuit breaker pattern — if OpenRouter is down, all requests will retry until timeout"],"requires":["Error handling middleware enabled in MCP server core","Logging infrastructure configured (see Logging and Observability)"],"input_types":["any request that may fail (search query, API call)"],"output_types":["typed error object with code, message, and retry metadata","structured log entry with error context"],"categories":["safety-moderation","automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_3","uri":"capability://data.processing.analysis.citation.extraction.and.response.metadata.structuring","name":"citation extraction and response metadata structuring","description":"Implements ResponseOptimizer class that parses Perplexity Sonar responses to extract citations (source URLs and titles), structure metadata (model used, query time, token counts), and format results for MCP protocol compliance. Converts raw API responses into a standardized JSON schema with separate sections for answer text, citations array, and metadata, enabling MCP clients to display sources and trace information provenance.","intents":["Display source citations in Claude/Cursor UI so users can verify search results","Track which sources informed the AI's response for transparency and fact-checking","Provide structured metadata (latency, model, token usage) for monitoring and debugging"],"best_for":["Teams building AI applications where source attribution is required","Compliance-heavy domains (legal, medical, financial) where provenance tracking is mandatory","Developers optimizing token usage and API costs"],"limitations":["Citation extraction depends on Perplexity Sonar's response format — format changes break parsing","No deduplication of citations — same source may appear multiple times if referenced in different contexts","Metadata extraction is model-specific — different Sonar variants may return different fields","No validation that cited URLs are actually accessible or relevant to the answer"],"requires":["Perplexity Sonar API response with citations field populated","ResponseOptimizer class instantiated in the search pipeline"],"input_types":["raw Perplexity Sonar API response JSON"],"output_types":["structured JSON with 'answer' (string), 'citations' (array of {url, title}), 'metadata' (object with model, latency, tokens)"],"categories":["data-processing-analysis","search-retrieval"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_4","uri":"capability://automation.workflow.model.configuration.system.with.runtime.selection","name":"model configuration system with runtime selection","description":"Implements model configuration via environment variables and CLI arguments that allow selecting between Perplexity Sonar variants (sonar, sonar-pro, sonar-reasoning-pro, sonar-deep-research) and Grok 4. Configuration is resolved at server startup and passed through the request pipeline to OpenRouter, enabling different deployments to use different models without code changes. Model characteristics (cost, latency, capability) are documented in AGENTS.md and MODEL_SELECTION_GUIDE.","intents":["Choose between fast/cheap (sonar) vs slow/capable (sonar-reasoning-pro) models based on use case","Run different Nexus instances with different models for A/B testing or cost optimization","Document model tradeoffs (latency, cost, reasoning depth) for informed selection"],"best_for":["Teams with heterogeneous search needs (some queries need reasoning, others need speed)","Cost-conscious deployments that want to use cheaper models for simple queries","Researchers comparing model performance on search tasks"],"limitations":["Model selection is static per server instance — cannot route different queries to different models","No automatic model selection based on query complexity — users must choose upfront","Model availability depends on OpenRouter's current offerings — Grok 4 or Sonar variants may be deprecated","No fallback mechanism if selected model is unavailable — request fails rather than degrading to alternative"],"requires":["OPENROUTER_MODEL environment variable or --model CLI flag","Model must be available in OpenRouter's catalog","Model documentation in AGENTS.md or MODEL_SELECTION_GUIDE for reference"],"input_types":["model name string (sonar | sonar-pro | sonar-reasoning-pro | sonar-deep-research | grok-4)"],"output_types":["model configuration object passed to OpenRouter API"],"categories":["automation-workflow","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_5","uri":"capability://safety.moderation.input.validation.with.json.rpc.schema.enforcement","name":"input validation with json-rpc schema enforcement","description":"Implements input validation layer that enforces JSON-RPC protocol compliance and validates search query parameters before sending to OpenRouter. Uses schema validation (likely JSON Schema or similar) to check query string length, model selection validity, and required fields. Validation errors are caught early and returned to MCP clients with descriptive error messages, preventing malformed requests from reaching the API.","intents":["Prevent invalid queries from being sent to OpenRouter, reducing wasted API calls","Provide immediate feedback to MCP clients when query parameters are malformed","Enforce JSON-RPC protocol compliance so clients know the expected request/response format"],"best_for":["Developers integrating Nexus with custom MCP clients that may send malformed requests","Teams that want to fail fast on invalid input rather than waiting for API errors","Compliance scenarios where request validation must be auditable"],"limitations":["Validation rules are static — no dynamic validation based on model or context","Query length limits are likely hardcoded — no per-model limits (e.g., reasoning-pro might support longer queries)","No semantic validation — validates structure but not query quality or relevance","Error messages may be technical (JSON Schema validation errors) rather than user-friendly"],"requires":["JSON-RPC validation schema defined in codebase","Input validation middleware enabled in MCP server core"],"input_types":["JSON-RPC request object with method, params, id fields"],"output_types":["validation error with code and message, or validated request object passed to search pipeline"],"categories":["safety-moderation","data-processing-analysis"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_6","uri":"capability://automation.workflow.structured.logging.and.observability.with.configurable.verbosity","name":"structured logging and observability with configurable verbosity","description":"Implements logging infrastructure with configurable verbosity levels (likely DEBUG, INFO, WARN, ERROR) controlled via LOG_LEVEL environment variable. Logs are structured (JSON or key-value format) and include context like request ID, model, query, latency, and error details. Enables debugging of search failures and monitoring of server health without code changes.","intents":["Debug search failures by examining detailed request/response logs","Monitor server health and API usage patterns in production","Trace request flow through the system for performance optimization"],"best_for":["DevOps teams running Nexus in production who need observability","Developers debugging integration issues with MCP clients","Teams analyzing API usage patterns and costs"],"limitations":["Logs are written to stdout/stderr — no built-in log aggregation or persistence","No structured tracing (e.g., OpenTelemetry) — logs are flat, not hierarchical","Verbosity is global — cannot enable DEBUG for specific requests or models","Sensitive data (API keys, query content) may be logged if not carefully filtered"],"requires":["LOG_LEVEL environment variable (DEBUG | INFO | WARN | ERROR)","Log output redirection configured (e.g., to file or log aggregation service)"],"input_types":["log level configuration"],"output_types":["structured log entries (JSON or key-value) written to stdout/stderr"],"categories":["automation-workflow","safety-moderation"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_7","uri":"capability://automation.workflow.cli.entry.point.with.argument.parsing.and.server.initialization","name":"cli entry point with argument parsing and server initialization","description":"Implements CLI entry point (src/cli.ts) that parses command-line arguments (model selection, port, timeout, log level) and initializes the MCP server with the specified configuration. Supports both direct execution (node src/cli.ts) and npx invocation (npx nexus-mcp). Handles graceful shutdown and signal handling (SIGTERM, SIGINT) to cleanly close connections.","intents":["Start Nexus server with custom configuration without editing environment variables","Enable zero-install deployment via npx nexus-mcp","Support containerized deployments where CLI args are preferred over env vars"],"best_for":["Developers running Nexus locally for testing","DevOps teams deploying Nexus in containers or serverless environments","Users who prefer CLI args over environment variables for configuration"],"limitations":["CLI argument parsing is likely basic — may not support all configuration options","No interactive mode — all configuration must be provided upfront","Signal handling may not gracefully drain in-flight requests — abrupt shutdown possible","No built-in process manager — requires external supervisor (systemd, Docker, PM2) for auto-restart"],"requires":["Node.js 18+ installed","npx available (comes with npm 5.2+) for zero-install execution","OPENROUTER_API_KEY environment variable set"],"input_types":["CLI arguments (--model, --port, --timeout, --log-level, etc.)"],"output_types":["MCP server listening on STDIO, ready to accept connections"],"categories":["automation-workflow","tool-use-integration"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_8","uri":"capability://tool.use.integration.mcp.protocol.server.with.stdio.transport.and.tool.registration","name":"mcp protocol server with stdio transport and tool registration","description":"Implements MCP server using @modelcontextprotocol/sdk that exposes search as a registered tool following the MCP specification. Server communicates with MCP clients (Claude Desktop, Cursor) via STDIO transport, handling JSON-RPC message marshaling, tool discovery, and resource management. Tool registration includes schema definition (input parameters, description) that clients use to understand how to invoke search.","intents":["Enable Claude Desktop and Cursor to discover and invoke search as a native tool","Standardize search integration across different AI assistants via MCP protocol","Allow MCP clients to understand search parameters through tool schema"],"best_for":["Claude Desktop and Cursor users who want integrated web search","Developers building MCP-compatible AI applications","Teams standardizing on MCP for tool integration across multiple assistants"],"limitations":["STDIO transport is single-threaded — cannot handle multiple concurrent requests efficiently","Tool schema is static — cannot dynamically adjust parameters based on model or context","No built-in authentication — relies on API key in environment, not MCP-level auth","Client discovery of tools depends on MCP client implementation — not all clients may expose all tools"],"requires":["@modelcontextprotocol/sdk package installed","MCP-compatible client (Claude Desktop, Cursor, or custom implementation)","STDIO transport available (not suitable for HTTP-only environments)"],"input_types":["JSON-RPC requests from MCP client"],"output_types":["JSON-RPC responses with tool results, following MCP protocol"],"categories":["tool-use-integration","automation-workflow"],"confidence":0.5,"matches":0,"success_rate":0},{"id":"awesome-nexus__cap_9","uri":"capability://tool.use.integration.openrouter.api.client.with.model.agnostic.request.marshaling","name":"openrouter api client with model-agnostic request marshaling","description":"Implements OpenRouterClient that abstracts OpenRouter API communication, handling authentication (API key injection), request formatting, response parsing, and error translation. Supports multiple models (Perplexity Sonar variants, Grok 4) through a unified interface, marshaling model-specific parameters into OpenRouter's request format. Handles API versioning and endpoint routing transparently.","intents":["Decouple search logic from OpenRouter API details so models can be swapped without changing search code","Handle API authentication and request formatting consistently across all searches","Translate OpenRouter API errors into typed exceptions for error handling layer"],"best_for":["Developers who want to swap search providers (e.g., from OpenRouter to direct Perplexity API) without rewriting search logic","Teams integrating multiple AI models through a single abstraction","Builders who want to mock OpenRouter for testing"],"limitations":["OpenRouter API changes require updating the client — no version negotiation","Model-specific parameters (e.g., reasoning depth for sonar-reasoning-pro) may not be fully exposed","No request batching — each search is a separate API call","API key is passed in every request — no connection pooling or session management"],"requires":["OPENROUTER_API_KEY environment variable with valid OpenRouter credentials","OpenRouter account with access to selected models"],"input_types":["search query string, model name, optional parameters"],"output_types":["parsed API response with answer, citations, metadata"],"categories":["tool-use-integration","data-processing-analysis"],"confidence":0.5,"matches":0,"success_rate":0}],"trust":{"score":27,"verified":false,"data_access_risk":"low","permissions":["Node.js 18+","OpenRouter API key with Perplexity Sonar model access","MCP-compatible client (Claude Desktop, Cursor, or custom MCP client)","OPENROUTER_API_KEY environment variable configured","TTL_CACHE_DURATION environment variable (default likely 300-600 seconds, exact value from config)","Concurrent request handling enabled in MCP server","Node.js 18+ installed","npm 5.2+ (comes with Node.js)","Internet access to npm registry","OPENROUTER_API_KEY environment variable"],"failure_modes":["Requires OpenRouter API key with Perplexity Sonar access — not free tier compatible","STDIO transport limits to single-threaded request handling per server instance","Model selection is static per server invocation — cannot switch models mid-session without restart","Response latency depends on OpenRouter backend availability and model inference time (typically 2-8 seconds)","TTL is global and configurable only via environment variable — no per-query TTL control","Cache is in-memory only — lost on server restart, no persistence layer","Deduplication window is request-level only — semantic similarity is not detected (e.g., 'weather in NYC' and 'NYC weather' are treated as different queries)","No cache invalidation mechanism — stale results may be served until TTL expires","First run downloads the package — adds 5-10 second startup latency","No offline mode — requires internet access to download from npm registry","builder identity is not verified yet","no observed match outcomes yet"],"rank_breakdown":{"adoption":0.05,"quality":0.49,"ecosystem":0.39999999999999997,"match_graph":0.25,"freshness":0.52,"weights":{"adoption":0.3,"quality":0.2,"ecosystem":0.15,"match_graph":0.3,"freshness":0.05}},"observed_outcomes":{"matches":0,"success_rate":0,"avg_confidence":0,"top_intents":[],"last_matched_at":null},"maintenance":{"status":"active","updated_at":"2026-06-17T09:51:03.579Z","last_scraped_at":"2026-05-03T14:00:15.503Z","last_commit":null},"community":{"stars":null,"forks":null,"weekly_downloads":null,"model_downloads":null,"model_likes":null}},"distribution":{"claim_url":"https://unfragile.ai/submit?claim=nexus","compare_url":"https://unfragile.ai/compare?artifact=nexus"}},"signature":"NiJ9G75XpBUh245Cu4+6k37B8j6BDOEHWOWzNREeysPXZ/wfIpqLlGo7rBfyFKl5PeiaYvYaP669s2i+hrvNAQ==","signedAt":"2026-06-21T07:45:58.213Z","signedBy":"unfragile.ai","version":1},"_links":{"self":"https://unfragile.ai/api/v1/passport/nexus","artifact":"https://unfragile.ai/nexus","verify":"https://unfragile.ai/api/v1/verify?slug=nexus","publicKey":"https://unfragile.ai/api/v1/trust-passport-public-key","spec":"https://unfragile.ai/trust","schema":"https://unfragile.ai/schema.json","docs":"https://unfragile.ai/docs"}}