Which AI agent startups publish MCP servers or llms.txt?

102 of the 128 AI agent infrastructure startups ranked by SalesBook publish an MCP server, an llms.txt file or both, by SalesBook's own check of their sites (61 MCP, 93 llms.txt). The highest-ranked are Modal, Relevance AI, You.com, Merge and Vapi; the list below shows each signal and when it was checked.

Updated 2026-10-22 · SalesBook ranking, methodology v0.3.0 · ranks are never for sale. See also agent-ready companies across all sectors.

Agentic rankings measure published agent interfaces (MCP, A2A, llms.txt) and the public evidence available, not verified Fortune 500 adoption or procurement approval.

Top 25 AI agent startups that publish MCP servers or llms.txt

1. Modal#1Cloud infrastructure for AI teams: GPU inference, training, serverless functions and isolated Sandboxes for coding agents and untrusted code.
   Investors: Accel, Kleiner Perkins, Menlo Ventures, General Catalyst, Redpoint, Lux Capital, Amplify Partners, Bain Capital Ventures · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: modal.com, checked 2026-10-22
2. Relevance AI#2Platform for enterprise teams to build and run AI agents for sales, support, marketing and operations.
   Investors: Bessemer Venture Partners, Insight Partners, Peak XV, King River Capital · MCP server: yes · llms.txt: yes (checked 2026-10-22) · Source: smartcompany.com.au, checked 2026-10-22
3. You.com#3Web search, contents and research APIs for AI agents and LLM developers, with enterprise plans.
   Investors: Cox Enterprises, Georgian, Salesforce Ventures, Norwest · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: about.you.com, checked 2026-10-22
4. Merge#4Unified API and Agent Handler that give software companies' AI agents authenticated, scoped access to third-party tools, with audit logs.
   Investors: Accel, NEA, Addition · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: merge.dev, checked 2026-10-22
5. Vapi#5Developer and enterprise platform for building, testing and deploying voice AI agents for phone and web calls.
   Investors: Peak XV, Y Combinator, M12, Kleiner Perkins · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: vapi.ai, checked 2026-10-22
6. WorkOS#6APIs for enterprise SSO, directory sync, audit logs and AuthKit, including auth for MCP servers and AI agents, sold to SaaS companies.
   Investors: Greenoaks, Lightspeed Venture Partners · MCP server: yes · llms.txt: yes (checked 2026-10-13) · Source: techcrunch.com, checked 2026-10-19
7. Synthflow#9Enterprise AI voice agent platform with its own telephony, used by contact centers, BPOs and enterprises to automate phone calls.
   Investors: Accel, Atlantic Labs, Singular · MCP server: yes · llms.txt: no (checked 2026-10-22) · Source: synthflow.ai, checked 2026-10-22
8. Comet (Opik)#10Opik, an open-source LLM and agent observability and evaluation platform, plus ML experiment management, sold to AI/ML teams and enterprises.
   Investors: OpenView, Scale Venture Partners, Trilogy Equity Partners, Two Sigma Ventures · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: comet.com, checked 2026-10-22
9. StackOne#11Integration infrastructure for AI agents: 560+ connectors and 35,000+ actions with managed auth, an MCP gateway and prompt-injection defense.
   Investors: GV, Workday Ventures, XTX Ventures, Episode 1, Playfair · MCP server: yes · llms.txt: yes (checked 2026-10-22) · Source: stackone.com, checked 2026-10-22
10. Profound#12AI visibility platform that shows brands how answer engines such as ChatGPT and Perplexity describe them, with agents that act on marketing tasks.
    Investors: Lightspeed Venture Partners, Sequoia Capital, Kleiner Perkins, Saga VC, South Park Commons · MCP server: yes · llms.txt: no (checked 2026-10-19) · Source: fortune.com, checked 2026-10-19
11. Weaviate#13Open-source vector database and AI platform for search, RAG and agents, offered as shared or dedicated cloud to AI teams and enterprises.
    Investors: Index Ventures, Battery Ventures · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: siliconcanals.com, checked 2026-10-22
12. Temporal#14Open-source durable execution platform and Temporal Cloud for running reliable applications and AI agents, sold to developers and enterprises.
    Investors: Andreessen Horowitz, Lightspeed Venture Partners, Sapphire Ventures, Sequoia Capital, Index Ventures, Tiger Global Management, GIC, Madrona Venture Group, Amplify Partners · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: thesaasnews.com, checked 2026-10-22
13. Exa#15Search API built for AI agents that returns real-time web results and page content, sold pay-as-you-go and to enterprises.
    Investors: Benchmark, Lightspeed Venture Partners, Y Combinator, NVentures · MCP server: yes · llms.txt: yes (checked 2026-10-19) · Source: lw.com, checked 2026-10-19
14. LlamaIndex#16Document agent and parsing platform (LlamaParse) plus open-source LlamaIndex framework for building agents over enterprise documents.
    Investors: Norwest Venture Partners, Greylock Partners · MCP server: yes · llms.txt: no (checked 2026-10-22) · Source: llamaindex.ai, checked 2026-10-22
15. LangChain#17Open-source agent frameworks (LangChain, LangGraph) plus LangSmith, a paid platform for building, tracing, evaluating and deploying agents for companies.
    Investors: IVP, Sequoia Capital, Benchmark, CapitalG · MCP server: yes · llms.txt: no (checked 2026-10-19) · Source: fortune.com, checked 2026-10-19
16. Raindrop#18Monitoring and issue detection for AI agents in production: tracing, silent-failure detection, triage and simulations for teams shipping agents.
    Investors: Lightspeed Venture Partners, Figma Ventures, Vercel Ventures, Y Combinator · MCP server: yes · llms.txt: yes (checked 2026-10-22) · Source: raindrop.ai, checked 2026-10-22
17. Nango#19Open-source, code-first integration platform that connects products and AI agents to 1,000+ APIs with auth, syncs, webhooks and MCP tools.
    Investors: Gradient, Horizon, Y Combinator · MCP server: yes · llms.txt: yes (checked 2026-10-22) · Source: nango.dev, checked 2026-10-22
18. Retell AI#20Voice AI agent platform for inbound and outbound phone calls, with chat and SMS, sold to healthcare, financial services and other enterprises.
    Investors: Alt Capital, Y Combinator, Carya Venture · MCP server: yes · llms.txt: yes (checked 2026-10-22) · Source: retellai.com, checked 2026-10-22
19. LiveKit#21Open source framework and cloud platform for building and running voice, video and physical AI agents, incl. telephony and inference.
    Investors: Index Ventures, Salesforce Ventures, Altimeter Capital, Redpoint Ventures, Hanabi Capital · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: fortune.com, checked 2026-10-22
20. Aembit#22Identity and access management for AI agents and non-human workloads, issuing short-lived credentials by policy instead of long-lived secrets.
    Investors: Acrew Capital, Ballistic Ventures, Ten Eleven Ventures, Okta Ventures, CrowdStrike Falcon Fund · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: aembit.io, checked 2026-10-22
21. Permit.io#23Fine-grained authorization as a service for apps, APIs and AI agents, including an MCP gateway that applies RBAC/ABAC/ReBAC to agent tool calls.
    Investors: Scale Venture Partners, NFX, Firestreak, Roosh Ventures, Verissimo Ventures · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: securityweek.com, checked 2026-10-22
22. Kernel#24Cloud browser API for AI agents and automations: isolated Chromium sessions, persistent profiles, managed auth, proxies and replays.
    Investors: Accel, Y Combinator · MCP server: no · llms.txt: yes (checked 2026-10-22) · Source: accel.com, checked 2026-10-22
23. E2B#27Open-source cloud sandboxes that give each AI agent an isolated machine to run code and tools, offered as a managed cloud or in the customer's own cloud.
    Investors: Insight Partners, Decibel, Sunflower Capital, Kaya · MCP server: yes · llms.txt: yes (checked 2026-10-19) · Source: e2b.dev, checked 2026-10-19
24. Composio#28Tool-calling and integration platform that connects AI agents to 1,000+ business apps with managed auth, sold to developers and enterprises.
    Investors: Lightspeed Venture Partners, Elevation Capital, Together Fund · MCP server: yes · llms.txt: yes (checked 2026-10-19) · Source: pulse2.com, checked 2026-10-19
25. Zep#29Context and memory layer for enterprise AI agents built on its open-source Graphiti graph engine.
    Investors: Y Combinator, Engineering Capital · MCP server: yes · llms.txt: yes (checked 2026-10-19) · Source: getzep.com, checked 2026-10-19

Questions

Which AI agent startups publish MCP servers or llms.txt?

102 of the 128 AI agent infrastructure startups ranked by SalesBook publish an MCP server, an llms.txt file or both, by SalesBook's own check of their sites (61 MCP, 93 llms.txt). The highest-ranked are Modal, Relevance AI, You.com, Merge and Vapi; the list below shows each signal and when it was checked.

How is this list ranked?

In SalesBook rank order under methodology v0.3.0, built only from dated public sources. Rankings are never for sale.

When was this list last updated?

2026-10-22: the most recent date a company on this list was checked against its public sources.