Click is a managed agents API for developers who want agents inside their own products. You set a model, instructions, and tools, open a session, and submit a task with an API call. Click runs the model and tool loop, stores conversation history, and handles recovery. Results return as a live stream of text, thinking, and tool activity, or as a signed webhook when the job is done. The application remains in charge of when the agent works, which tools it can call, and how output reaches users. This launch is for product teams that would otherwise keep rebuilding agent infrastructure as models and tools change. Sessions include a sandbox, a browser, and web search, so an agent can run code, browse, and research without the product team operating those environments. Developers bring their own model keys and can connect MCP servers or custom HTTP tools, with permissions and credentials scoped to each session. The runtime also includes deferred tool discovery for thousands of tools and a code mode that calls tools from scripts. Click is in Y Combinator's S26 batch. Founder Aditya Asgaonkar, based in San Francisco, previously worked as a research engineer at the Ethereum Foundation, where he helped build Ethereum's proof-of-stake system.