Consumer Tags
MCPX allows connections to declare the consumer group they belong to using the x-lunar-consumer-tags HTTP header.
A consumer, in this context, is any client connecting to MCPX, typically an application or service integrated with an LLM on one end and MCPX on the other, in order to call one or more MCP compatible tools.
A consumer group represents a logical grouping of those consumers—for example, all requests coming from a specific team, environment, or use case. Tags let you define and track those groups explicitly.
MCPX uses these tags to power access control, rate limiting, and observability.
Why Consumer Tags?
Many systems need to apply different rules or limits based on who is making a request or how it’s being used. But in AI-based or multi-agent systems, identities can be fuzzy or dynamic.
Consumer tags let you:
- Distinguish between teams, tenants, or environments (e.g.
team:alpha,env:prod) - Apply ACLs selectively (e.g. restrict
delete_userto trusted tags) - Rate-limit based on tag groups instead of raw IPs or keys
- Power dashboards and metrics with useful request-level context
Format
x-lunar-consumer-tags is a comma-separated list of key:value pairs sent as an HTTP header.
Example:
x-lunar-consumer-tags: team:alpha, env:staging, purpose:testing