Core Concepts

MCP instances

The tool surface provisioned for each verified connection.

When a connection verifies, PopMCP provisions an McpInstance, the hosted MCP surface for that provider connection.

What an instance exposes

Every instance exposes the provider's toolset under a prefix such as klaviyo_, shopify_ or stripe_, plus three tools that make the rest of the provider's API reachable without flooding the client's context:

ToolPurpose
<prefix>_search_toolsFuzzy-search the provider's full operation catalog
<prefix>_describe_toolReturn the full input schema for one tool by name
<prefix>_raw_operationEscape hatch, calls any operation by its toolSuffix

The curated toolset is the high-value subset a model should see eagerly. The full catalog stays reachable through search and the escape hatch, so a small default list costs nothing.

The aggregated surface

At the account level the gateway also exposes list_connections, which tells a client which connections it has been granted. Each provider toolset takes a connection selector argument, so a client holding two Klaviyo connections addresses them explicitly.

Every tool call executes against the resolved connection's own instance, never a shared representative. Two connections for the same provider cannot cross credentials.

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