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Introduction Getting started Write an agent Project anatomy

Understand Ayjnt

Harness engineering Two runtimes Human interfaces How agents work Host bridge

Agent capabilities

Callable methods State & SQLite Sessions & memory Scheduling Workflows Durable execution Inter-agent RPC Sub-agents Tools

Interfaces & integrations

Browser client Routing & middleware Voice Browser tools MCP Email Observability

CLI

Command overview new dev run build compile migrate deploy

API reference

Agent AgentClient Workflow classes Local & cloud Migrations Examples

Architecture

Two runtimes, one harness

Ayjnt separates isolated agent execution from host capabilities, then connects them through a typed, permission-aware bridge.

Human You choose the interface

app.tsx browser cli.ts terminal

Agent runtime

Safe, stateful, instant.

Agents run in workerd V8 isolates, with durable state, scheduling, workflows, and agent-to-agent RPC.

workerdisolatedeployable

typed bridge tools cross with explicit permissions

Host runtime

Close to the machine.

Host actions run in Bun, where agents can work with files, shells, databases, processes, and local connectors.

Bunlocalpermissioned

Human You choose the interface

app.tsx browser cli.ts terminal

requests

Agent runtime · workerd

Safe, stateful, instant.

Agents reason in isolated V8 environments with durable state, scheduling, workflows, and agent-to-agent RPC.

isolatedeployable

typed bridgetools cross with explicit permissions

Host runtime · Bun

Close to the machine.

Host actions work with files, shells, databases, processes, and local connectors.

localpermissioned

The agent runtime

Agent classes, durable state, schedules, workflows, and in-runtime tools execute in workerd. Each stateful agent instance is backed by a V8 isolate, providing a lightweight boundary that starts quickly and scales to large numbers of concurrent agents.

This side of the harness is portable between local workerd and Cloudflare. It is the right place for coordination, model calls, state machines, and tools that do not need native host access.

The host runtime

The CLI and host tools execute in Bun. This is where a harness can use Bun.file, Bun.$, bun:sqlite, local processes, and connectors that belong to the machine running the harness.

Host tools declare whether they read, write, or execute. Ayjnt can then gate meaningful side effects instead of treating every tool call as equally trusted.

The bridge

An agent sees one merged tool set. Workerd-native tools execute beside the agent. Host tools are represented by typed proxies and cross an internal bridge only when called. The host validates the declared permission before running the tool.

Concern	Agent runtime	Host runtime
Runtime	workerd / V8 isolates	Bun
Best for	state, orchestration, model loops	files, shells, native APIs
Tool file	`tools.ts`	`tools.host.ts`
Cloud deploy	Yes	No host process in cloud deployments