Horton agent

The built-in assistant registered by the Electric Agents dev server. Horton can chat conversationally, search the web, read and edit files, run shell commands, and dispatch workers for isolated subtasks.

Source: packages/agents/src/agents/horton.ts

Try it

With the dev server running (npx electric-ax agents quickstart):

npx electric-ax agents spawn /horton/my-horton
npx electric-ax agents send /horton/my-horton 'What's in this directory?'
npx electric-ax agents observe /horton/my-horton

Tools

Horton is configured with ctx.electricTools plus the base Horton tool set:

Tool	Purpose
bash	Run shell commands in the working directory.
read	Read a file. Tracked in a per-wake readSet.
write	Create or overwrite a file.
edit	Targeted string replacement (file must be read first).
brave_search	Web search via the Brave Search API.
fetch_url	Fetch a URL and return it as markdown.
spawn_worker	Dispatch a subagent for an isolated subtask.

brave_search requires BRAVE_SEARCH_API_KEY in the environment; without it the tool errors at call time.

When docs support or skills are available, Horton also adds the docs search tool and skill tools during bootstrap.

Title generation

After the first agent run completes, Horton calls generateTitle() (Haiku) to summarise the user's first message into a 3-5 word session title and stores it via ctx.setTag('title', title). Failures are logged and ignored — the entity continues without a title.

Details

Property	Value
Type name	horton
Model	HORTON_MODEL (claude-sonnet-4-5-20250929)
Title model	claude-haiku-4-5-20251001
Tools	ctx.electricTools + base Horton tool set, plus docs/skill tools when configured
Working directory	Passed at bootstrap (defaults to process.cwd())
Title generation	Yes, after the first run if no title tag exists

Extending Horton

The system prompt and tool factory are exported so you can build your own variants:

import {
  HORTON_MODEL,
  buildHortonSystemPrompt,
  createHortonTools,
} from "@electric-ax/agents"

registry.define("my-assistant", {
  description: "Horton with an extra custom tool",
  async handler(ctx) {
    const readSet = new Set<string>()
    ctx.useAgent({
      systemPrompt: buildHortonSystemPrompt(process.cwd()),
      model: HORTON_MODEL,
      tools: [
        ...ctx.electricTools,
        ...createHortonTools(process.cwd(), ctx, readSet),
        myCustomTool,
      ],
    })
    await ctx.agent.run()
  },
})

Related

• Worker — the subagent type Horton dispatches via spawn_worker.