---
name: orchardcore-ai-a2a-host
description: Skill for configuring the CrestApps A2A Host feature in Orchard Core. Covers exposing Agent AI Profiles as A2A agents, host authentication, agent cards, endpoints, and host settings. Use this skill when requests mention Orchard Core A2A Host, Configure an A2A Host, Feature Overview, Enable the Host Feature, Create Agent Profiles, Host Settings in Configuration, or closely related Orchard Core implementation, setup, extension, or troubleshooting work. Strong matches include work with CrestApps.OrchardCore.AI.A2A.Host, CrestApps.OrchardCore.AI, AIProfile, ExposeAgentsAsSkill, agentName, AuthenticationType, OrchardCore:CrestApps_AI:A2AHost, ApiKey. It also helps with Create Agent Profiles, Host Settings in Configuration, Agent Exposure Modes, plus the code patterns, admin flows, recipe steps, and referenced examples captured in this skill.
license: Apache-2.0
metadata:
  author: CrestApps Team
  version: "1.0"
---

# Orchard Core A2A Host - Prompt Templates

## Configure an A2A Host

You are an Orchard Core expert. Generate configuration and guidance for exposing Orchard Core Agent AI Profiles through the CrestApps A2A Host feature.

### Guidelines
- Use the A2A Host feature ID `CrestApps.OrchardCore.AI.A2A.Host`.
- The host exposes AI Profiles whose `Type` is `Agent`.
- Agent cards are served from `/.well-known/agent-card.json`.
- By default, the well-known endpoint returns a JSON array of agent cards, one per Agent AI Profile.
- Each card points to `/a2a?agent={agentName}` through its `url` property.
- When `ExposeAgentsAsSkill` is enabled, the host returns a single combined agent card and routes requests using the `agentName` metadata field.
- Keep agent `Description` accurate because it becomes part of the external agent or skill description.
- Prefer authenticated host access in shared or production environments.

### Feature Overview

| Feature | Feature ID | Description |
|---------|-----------|-------------|
| A2A Host | `CrestApps.OrchardCore.AI.A2A.Host` | Expose Agent AI Profiles via the Agent-to-Agent protocol |

### Enable the Host Feature

```json
{
  "steps": [
    {
      "name": "Feature",
      "enable": [
        "CrestApps.OrchardCore.AI",
        "CrestApps.OrchardCore.AI.A2A.Host"
      ],
      "disable": []
    }
  ]
}
```

### Prerequisite: Create Agent Profiles

Only AI Profiles of type `Agent` are exposed by the host.

The `AIProfile` recipe format is source-agnostic. Omit `Source` and bind the agent to deployments by technical name.

```json
{
  "steps": [
    {
      "name": "AIProfile",
      "profiles": [
        {
          "Name": "research-agent",
          "DisplayText": "Research Agent",
          "Description": "Researches topics and returns sourced summaries.",
          "Type": "Agent",
          "ChatDeploymentName": "research-chat",
          "UtilityDeploymentName": "research-utility",
          "Properties": {
            "AIProfileMetadata": {
              "SystemMessage": "You are a research assistant.",
              "Temperature": 0.2,
              "MaxTokens": 4096
            },
            "AgentMetadata": {
              "Availability": "OnDemand"
            }
          }
        }
      ]
    }
  ]
}
```

### Host Settings in Configuration

```json
{
  "OrchardCore": {
    "CrestApps_AI": {
      "A2AHost": {
        "AuthenticationType": "None",
        "ApiKey": "your-api-key-here",
        "RequireAccessPermission": false,
        "ExposeAgentsAsSkill": false
      }
    }
  }
}
```

### Agent Exposure Modes

#### Multi-Agent Mode (Default)

Use `ExposeAgentsAsSkill: false` when you want one agent card per Agent profile.

- `/.well-known/agent-card.json` returns a JSON array of cards.
- Each card advertises a single agent.
- Each card points clients to `/a2a?agent={agentName}`.

#### Skill Mode

Use `ExposeAgentsAsSkill: true` when you want a single combined agent card.

- The well-known endpoint returns one combined card.
- Each Agent AI Profile is represented as a skill.
- Requests are routed using the `agentName` metadata field.

### Endpoints

| Endpoint | Purpose |
|----------|---------|
| `/.well-known/agent-card.json` | Agent discovery endpoint |
| `/a2a?agent={agentName}` | Sends messages to a specific exposed agent |

### Authentication Guidance

The host configuration supports authentication settings through `AuthenticationType` and related options in `OrchardCore:CrestApps_AI:A2AHost`.

Use these settings as your starting point:

- `AuthenticationType: "None"` for local development only.
- Set `ApiKey` when using API-key-based access.
- Use `RequireAccessPermission: true` when you want Orchard permission checks enforced for host access.

### Example Host Configuration for a Shared Environment

```json
{
  "OrchardCore": {
    "CrestApps_AI": {
      "A2AHost": {
        "AuthenticationType": "ApiKey",
        "ApiKey": "{{A2AHostApiKey}}",
        "RequireAccessPermission": true,
        "ExposeAgentsAsSkill": true
      }
    }
  }
}
```

### Best Practices

- Use Agent profiles, not Chat profiles, for A2A host exposure.
- Write strong profile descriptions so remote clients can pick the right agent.
- Keep `ExposeAgentsAsSkill` disabled when clients should select named agents directly.
- Enable `ExposeAgentsAsSkill` when clients prefer one consolidated card with multiple skills.
- Avoid `AuthenticationType: "None"` outside local development.