Pre-built and custom connectors
520+ connectors and 32,000+ actions, built and maintained for CRM, ERP, HR, finance, IT and knowledge tools. Anything the catalogue does not cover, the Connector Builder adds.
Tool Gateway MCP
One universal MCP Gateway, one URL. Every employee’s AI reaches your systems under their own permissions, within limits IT set.
https://mcp.stackone.com/mcp An employee asks their AI assistant — Claude, ChatGPT, M365 Copilot, Glean, Gemini Enterprise or any of 60+ clients. The assistant reaches the StackOne Tool Gateway MCP over one URL. Above the gateway, the IT team picks which connectors, actions and field rules it allows before anyone connects. The gateway then calls the business systems behind it, 32,000+ actions across 520+ apps.
The answer
Reach
A pilot touches three systems. A rollout touches all of them, and each one is something you ship and then keep alive. Then one team picks a different assistant and you do it all again.
Connect
Connect StackOne once and every AI assistant in the company is served. No build per app, and nothing to redo when a team switches assistant.
How connection worksControl
Once everyone is connected, assistants write to your systems of record all day. The log shows the server ran a tool, with no name behind it and no assistant it came from, and nothing stops the next one.
Secure
You can see what every assistant is doing in your business systems. Each call runs under that person’s own permissions, and nobody has to wait for it.
How governance worksCost
Most assistants take about 100 tools from one server. List your actions directly and two systems use up the lot, so the third never loads. What did load costs tokens on every call and makes the model worse at picking the right one.
Optimize
Most MCP servers push the whole tool catalogue into the context window. Token bills climb and the model reasons worse. StackOne sends two tools and fetches the rest when a task needs them.
How Tool Discovery worksCompanies already connected through StackOne
Connect
520+ connectors and 32,000+ actions, built and maintained for CRM, ERP, HR, finance, IT and knowledge tools. Anything the catalogue does not cover, the Connector Builder adds.
One URL, and it is the same one for every customer and every client. Adding it to an assistant is pasting a link, and StackOne supports all three ways clients register, so there is nothing to build per client.
Pick which connectors and actions each group can use, then paste the Tool Gateway MCP URL into your AI client. One URL covers every assistant.
Each person signs in from the chat window they already have open, and authorises their own accounts through each system’s own login.
Actions run under that person’s own permissions. Every call is logged in StackOne with the assistant it came from and the person behind it.
60% of AI deployments fail because of integrations
Read why Connect mattersSecure
Every call records the assistant it came from and the verified user who ran it, not a shared service account, so one view covers every person across every assistant your team uses.
Turn on three of 128 actions, then decide field by field what a write may touch. Names and work email allowed, compensation and manager held for approval, national id never written.
Every action is tagged read-only or write, so the assistant approves reads on its own and holds writes and deletes for a person to sign off.
StackOne stores and refreshes the OAuth tokens. The assistant never sees a credential.
Personal credentials keep an assistant inside one employee's permissions. Shared credentials reach team and company tools, still under IT control.
An Ungoverned Agent Is a Liability: 10 prompt injection examples
Read why Secure mattersOptimize
Query
Results
workday_create_learning_enrollment
96%workday_update_employee_record
42%
workday_send_notification
31%
workday_create_task
18%
workday_list_learning_courses
14%
workday_assign_compliance_policy
9%
Most assistants cap one server at around 100 tools, and two systems listed directly fill it. StackOne uses a search tool and an execute tool and fetches the rest when a task needs them.
Search and aggregate across connected systems without hitting tool response limits. The answer is not capped by what one response can carry in a prompt.
Token spend scales with what the agent is doing, not with the size of your catalogue.
Adding connectors does not make the model worse at choosing, because the tool list never reaches it.
The execution layer the connectors run on, so calls return fast and predictably in every assistant you connect.
Context Bloat Makes Your Agent Slow, Costly, and Unreliable
Read why Optimize mattersWho this is for
Add MCP server
https://mcp.stackone.com/mcpConnected servers
Searching & Executing actions
StackOne Layer
Done in 12.3s
Choose the accounts and actions Assistant can access.
2 accounts selected 415 actions selected
Tool Gateway vs MCP Gateway
| What has to happen at the endpoint | An MCP gateway | StackOne Tool Gateway MCP |
|---|---|---|
| Both do this | ||
| One endpoint, with auth and policy on every call | Included | Included |
| An audit trail of what was called | Included | Included |
| Only a tool gateway | ||
| The tools themselves | Fronts MCP servers that already exist, yours or a vendor’s | Included. Built and maintained by StackOne: 520+ apps, 32,000+ actions |
| Customising what a connector returns | Out of scope | Included. Connector Builder, down to the field |
| Context cost as the catalogue grows | Curates which tools are approved; every one of them still loads into the window | Included. Two tools in context, schemas fetched only when a task needs them |
| Per-action risk signals | Only what each underlying server emits | Included. MCP Annotations on every action |
| Working when nobody is in a chat window | Nothing happens until someone asks | Included. Agent Webhooks fire on events; Deep Query answers across systems |
What a tool gateway does that an MCP gateway does not
Read the full comparisonFAQ
An MCP gateway is a single Model Context Protocol endpoint that AI clients connect to instead of being wired into each business system separately. Every tool call goes through it, so it is the one place an organisation can decide who an agent is acting as and what it may reach. How much of that a gateway does varies a lot. Many handle routing and little else.