Version binding

Understand how the Processes MCP Server handles process version binding, stale tool references after redeployment, and best practices for managing breaking changes.

Which version is exposed

The Processes MCP Server always exposes only the latest deployed version of a process. When you deploy a new version of a process, it replaces the previous version's tool registration. There is no mechanism to pin an MCP client to a specific process version.

Stale tool references

MCP clients typically cache the tool list after connecting. If a client cached the tool list before a redeployment and then attempts to call the now-replaced tool, it receives an error instructing it to refresh its tool list by running tool discovery again.

MCP clients must therefore:

1. Handle the stale-tool error gracefully.
2. Re-fetch the tool list by running tool discovery again before retrying.

Implications for process owners

Redeploying a process with a changed interface, such as a different tool name, input parameters, or output variables, is a breaking change for any MCP client currently holding a reference to that tool.

To reduce disruption:

• Communicate planned redeployments to teams operating MCP clients that use your process tool.
• When making a significant interface change, consider deploying a new process with a different tool name rather than redeploying over the existing one. This lets existing clients continue using the old version while new clients adopt the updated tool.