Q & A

Is MCPBus open source?

The core MCPBus binary is proprietary, but it stands on the shoulders of giants. We proudly use open-source packages. You can view the full list of third-party licenses directly in your terminal at any time by running:

mcpbus --licenses

Does MCPBus require external network access?

No. MCPBus runs in 100% off-line local mode by default. It doesn't require external network access unless your APIs from your OpenAPI spec have publicly available endpoints. You can run MCPBus inside your local corporative network no problem.

Does MCPBus transmit any of my data "outside"?

No. The core binary requires no internet connection to parse OpenAPI specs or route local traffic. No telemetry sent or any kind of data retention. We never log, collect, or transmit outside your OpenAPI schemas, API keys, MCP-tools parameters/outputs or prompt payloads.

Does MCPBus require any dependencies to be installed?

No. MCPBus compiles directly into a single, highly optimized, self-contained binary with zero external dependencies. All you need is an MCPBus executable binary.

What MCP version is supported?

MCPBus supports the latest MCP protocol version 2025-11-25.

What MCP-authentication types are supported?

MCPBus does provide to MCP-clients only one authentication type (optional) at the moment: bearer token.

What OpenAPI specification versions are supported?

MCPBus fully supports OpenAPI v2.0 and OpenAPI v3.0 at the moment.

Ok, my APIs are also protected. What OpenAPI security schemes does MCPBus support?

MCPBus does support the following OpenAPI security schemes to call your APIs:

• http type, schemes bearer and basic
• apiKey type

Will MCPBus provide to AI-agents any destructive tools?

No. The destructive operations (DELETE, PUT, PATCH) are blocked by default unless you pass the --openapi-allow-destructive=true CLI-flag.

My OpenAPI spec is big. How can I avoid the LLM context bloat?

You can use either --openapi-endpoints-include=... or --openapi-endpoints-exclude=... CLI parameters to specify list of endpoint to include, or to exclude certain endpoints from the generated MCP-tools list.

My OpenAPI spec has lots of local $ref. What MCPBus does with them?

MCPBus resolves all local $ref's per endpoint into one fully inline JSON schema, for both MCP-tool input parameters (including request payload JSON schema) and tool's output schemas. So your LLM will receive one inline JSON schema which is easy to understand.

My OpenAPI spec has local recursive $ref. How MCPBus does deal with them?

MCPBus process JSON schemas with recursive $refs into one inline flat JSON schema so your LLMs won't have to parse and resolve all recursive references. The nested recursive structures receive JSON schemas with the same title as the referenced (enclosing/parent) schema and special hints for LLMs in description. These hints identify that this part of schema is nested and has already specified in one of outer nodes of the current JSON schema.

I use MCPBus and love it! How can I get support?

Please check out Support / Contacts