Registry agent nodes connect a master agent node (task orchestrator) to agents published in the Agent Registry. Unlike a standard agent node configured only with prompts and tools, a registry agent node references an A2A registration—either a specific agent (Browse) or a dynamic set matched at runtime (Discovery).
Browse Discovery Agents
The browse panel title in the product reads Agent Block; documentation uses Agent Node for consistency with Graph Studio agent nodes.

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When to use Browse vs Discovery

Both modes require agents to be exposed in the registry with appropriate visibility, skills, and tags. See Expose your agent graph.

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Open the registry panel

  1. Open Graph Studio for your project.
  2. Add or select an agent node on the canvas under a master (task) agent node.
  3. When the node is unconfigured—or when you open registry tooling—the Browse / Discovery panel appears on the right.
The panel loads registry data via GET /a2a-registry?workspaceid=...&orgid=....

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Browse mode

In Browse mode:
  1. Search and filter agents (visibility, deployed status, MIME modes, tags)—same dimensions as Agent Registry catalog.
  2. Select an agent card from the list.
  3. Review the Agent Card preview (hosted URL, skills, build status).
  4. Click to add the agent to the canvas (or replace the current registry agent node).
After selection, configure tools and environment variables exported with that registry build in the Configuration sub-view. Browse nodes persist:
  • a2aregistryid, config_id, flowid, status, apikeyid
  • agent_node_type: "browse"
Validation requires a connected configuration (config_id) and satisfied tool/env requirements before save or publish.

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Discovery mode

In Discovery mode the master agent does not point at one fixed registration. Instead you define Discovery filters; at runtime the platform finds registry agents that match.
Discovery Filters

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Set Discovery filters

Configure filters parallel to the catalog sidebar: Click Save Filters to create a Discovery Agent node on the canvas with:
  • agent_node_type: "discovery"
  • discovery_filters — saved filter object
  • Default display name: Discovery Agent
Copy shown in the UI:
In Discovery Mode, the Master Agent will find and attach the agents automatically based on your filter criteria.

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Configure Discovery API key

After saving filters, open the Configuration sub-tab to select the API key the master agent uses when calling discovered agents (apikeyid on the node).
Discovery Configuration

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One Discovery node per master agent

Only one Discovery registry agent node is allowed per master (task) agent node. If you try to add a second, the Studio shows Discovery Already Connected (or the Discovery tab is disabled with Only one discovery allowed per master agent node).
Discovery nodes skip the standard per-tool configuration validation used in Browse mode—the filter set defines what may be attached at runtime.

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Persisted node fields

When you save or publish the agent graph, registry agent nodes include:

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Permissions

  • Configure registry nodes: flow_gen.studio.save_flow and related Graph Studio permissions
  • Load registry list: assistants.flows:read

Browse the catalog

Full workspace search and filters.

Endpoints & lifecycle

Hosted URLs and visibility at invoke time.

Agent node anatomy

Prompts, RAG, tools, and variables on standard agent nodes.