Agent infrastructure products for AI builders
Downcity is not one tool. It is one reusable runtime layer across local agent hosting, City SDK, Federation SDK, Agent SDK, UI SDK, and official services for many agent products and workflows.
Products, Agents, and City Runtime
Products own the real experience, agents execute the work, and Downcity runtime owns the repeated infrastructure: models, tools, tasks, memory, permissions, usage, billing, services, and observability.
AI products and workflow entry points
Run long-lived execution
Models / services / auth / usage / billing
Products
Can be web apps, extensions, desktop apps, mobile apps, client demos, internal tools, or API hosts.
Agents
Run inside explicit boundaries and handle tasks, context, tool calls, and long-term state.
City Runtime
Centralizes the agent backend capabilities that every new AI product would otherwise rebuild.
app/cli/
Downcity CLI
The official CLI for initializing, starting, managing, and debugging local agent runtime.
packages/city/
City SDK
Host local Agent instances and expose them to product clients behind a Service, Action, and AIService boundary.
packages/federation/
Federation SDK
Model catalogs, service routing, auth, runtime env, usage, balance, and payment: one backend for many agent products.
packages/agent/
Agent SDK
Embed local agents, RemoteAgent clients, sessions, and host extension ports into your application flow.
packages/ui/
Downcity UI SDK
Reuse Downcity UI patterns to build your own agent-facing workspace faster.
packages/implementations/services/
Services & Payment
Official accounts, credits, payment, and usage services that bring billing and metering into your agent product.
Product Facts
- Downcity is for AI builders: the core value is reusing one runtime infrastructure across many agent products.
- Downcity CLI is the official command-line implementation under app/cli/.
- City SDK host and HTTP/RPC forwarding capabilities live in packages/city/.
- Federation SDK owns model catalogs, service routing, auth, usage, billing, and payment in packages/federation/.
- Agent SDK local Agent and RemoteAgent runtime are in packages/agent/.
- Downcity UI SDK is the React + Tailwind component package under packages/ui/.