The built-in tools

The hub ships four tools. This page lists what each tool gives to other apps and what it takes from the hub. For how topics, actions and capabilities work, see Connect to other tools.

Tool	Id	Default port
Kanban	kanban	3541
Marketplace	marketplace	3542
Cost	cost	3543
Memory Diagnoser	memory	3544

Who sends and who receives: a dot is the sender, an arrow is a receiver

• Topics. The hub publishes project.changed when you pick a project. Kanban filters its sessions to the project, Marketplace and Memory Diagnoser show that project, and Cost limits its totals to it. Kanban publishes session.changed when you open a session. No built-in tool subscribes to it, but your own apps can, as the Inspector does.
• Actions. Kanban calls project.plugins, session.cost and project.memory from the session view. Any app can call them.
• Capabilities. The hub reads projects and terminal from Kanban.

A fork or patch wrapper of a built-in tool starts from that tool’s manifest. The npm packages of the built-in tools do not include hub-app.json. Copy it from the tool’s GitHub repository.

Topics

session.changed

Kanban publishes the session that is open in it.

{
  "sessionId": "d3a7c2e1-5b4f-4c8e-9a12-6f0e8b7d4c31",
  "project": "C:\\demo\\api-gateway",
  "encoded": "C--demo-api-gateway",
  "projectName": "api-gateway",
  "name": "Rate limit for the orders API",
  "gitBranch": "feat/orders-rate-limit",
  "live": false,
  "source": "user"
}

Field	Meaning
sessionId	The session id
project	The absolute path of the session’s project. The hub adds encoded and projectName
name, gitBranch	The session name and branch, or null
live	True while the session works or waits for the user
source	user for a pick in the Kanban page, cli for claude-code-kanban session open

The payload is null when no session is open. Kanban publishes it when a pick stays the same for 150 ms, so a move through the list with the arrow keys sends one event. It does not publish it again for the same session.

The Inspector and the Task board subscribe to it.

Actions

Kanban calls all three actions from the session view. It shows each button only when hub.can() is true.

session.cost

Handler	Cost
Params	session?: a session id
URL	?view=detail&session={session}
Mode	message
Shows	The cost of that session. With no session, Cost comes on screen and keeps its view

await hub.invoke('session.cost', { session: 'd3a7c2e1-5b4f-4c8e-9a12-6f0e8b7d4c31' });

project.plugins

Handler	Marketplace
Params	project?: an absolute path
URL	?project={project}
Mode	message
Shows	The plugins of that project

project.memory

Handler	Memory Diagnoser
Params	project?: an absolute path
URL	?project={project}
Mode	message
Shows	The memory files of that project

To run the same calls with no hub, Kanban gives connect a standalone map built from its --cost-url, --marketplace-url and --memory-url flags.

Capabilities

Kanban provides both capabilities. To take one over, see Capabilities.

projects

GET /api/projects answers the projects that have sessions, sorted by path:

[
  { "path": "C:\\demo\\api-gateway", "modifiedAt": "2026-09-29T09:58:00.000Z" },
  { "path": "C:\\Users\\me\\AppData\\Local\\Temp\\scratch", "modifiedAt": null, "temp": true }
]

modifiedAt is the time of the last session change, or null. temp is true for a project in a temp folder. The hub shows the list in the project palette (Ctrl+Alt+P).

terminal

Kanban runs the embedded terminal. GET /api/terminals answers {sessions: [...]}, one entry for each open terminal. While the list is not empty, the hub keeps that set of apps in its pool when you switch config dirs. POST /api/apps/kanban/restart answers 409 while Kanban has open terminals, unless the body has force: true.