Defining agents

Agents are declared in YAML manifests. The file's id is the agent's identifier; kind selects one of four agent types. The same manifest runs unchanged in embedded mode, hosted mode, and self-hosted mode.

Anatomy of a manifest

agents/sentiment-analyzer.yaml

id: sentiment-analyzer            # required, unique within the registry
name: Sentiment Analyzer          # optional, display label
description: Tags text positive/negative/neutral
kind: llm                         # llm | tool | sequential | parallel

inputSchema:                      # optional — what the agent expects
  text: string

model:                            # required for kind: llm
  provider: openai
  name: gpt-5.4-nano
  temperature: 0

instruction: |                    # required for kind: llm — the system prompt
  Analyze the sentiment of the following text and respond with a JSON object.

  Text: {{text}}

outputSchema:                     # optional — what the model must return
  sentiment:
    type: string
    enum: [positive, negative, neutral]
  confidence: number

A manifest is just data — there's no code to maintain alongside it. The runner validates it on load, registers it with the runtime, and exposes it through the same client.agents.run API regardless of where it runs.

Defining agents

Anatomy of a manifest

Read next