Groups

A Group is a single named collection that scopes MCP primitives together — currently tools and prompts, with more (such as resources) planned. Where a Toolset groups only tools, a group bundles these primitives under one name and one MCP endpoint, and carries a description that describes the collection.

Connecting to a group’s endpoint (/mcp/{name}) scopes the corresponding MCP list methods (such as tools/list and prompts/list) to that group.

Defining Groups

Declare a group as a kind: group document in your configuration file. A group has the following fields:

* name is required for every named group. The single default group omits it.

As Toolbox adds support for more MCP primitives, groups will gain corresponding fields (for example, resources).

kind: group
name: data_analyst
description: Tools and prompts for exploratory data analysis.
tools:
  - list_tables
  - execute_sql
prompts:
  - summarize_results
---
kind: group
name: admin
description: Administrative operations.
tools:
  - create_user
  - list_users

The default group

A single default (nameless) group always exists and contains all configured primitives (every tool and prompt). Connecting to the default MCP endpoint (/mcp) returns everything.

You may declare a kind: group document with no name to set a description for the default group. Because the default group always contains everything, it cannot declare tools, prompts, or any other primitive list:

kind: group
description: All tools and prompts available on this server.

Validation rules

At startup, Toolbox validates groups:

• Unique names. A named group must have a unique name that satisfies the standard name rules (alphanumeric characters, underscores, and hyphens).
• One default group. Declaring more than one nameless group is an error.
• Default group restrictions. The default group may set only a description; declaring tools, prompts, or any other primitive list on it is an error.
• Group wins over a same-named toolset. If a name is defined by both a kind: toolset and a kind: group, the group takes precedence and Toolbox logs a warning naming the shadowed toolset.

Relationship to toolsets

Groups are a superset of toolsets: a toolset is equivalent to a tools-only group. Existing kind: toolset configurations continue to work unchanged — they are treated as groups with tools and no other primitives, so no migration is required. That said, we recommend migrating to a kind: group even for tools-only collections: a group lets you attach a description and scope prompts (and, in the future, other primitives) alongside tools. See Toolsets for more.