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Registry agent nodes let a Master Agent call other exposed A2A agents. Browse picks one registration; Discovery matches agents at runtime using saved filters.
Registry agent nodes connect a Master Agent node to agents published in the Agent Registry catalog. 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 and Discovery filters in Graph Studio

Browse / Discovery panel — attach registry agents on the canvas

The browse panel title in the product may read Agent Block; documentation uses Agent Node for consistency with Graph Studio.

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When to use Browse vs Discovery

Both modes require agents to be exposed 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 Agent Graph.
  2. Add or select an agent node on the canvas under a Master 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

  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).
  5. Configure tools and environment variables exported with that registry build in the Configuration sub-view.
  6. Save the graph — node stores agent_node_type: "browse", a2aregistryid, and config_id.
Validation requires a connected configuration (config_id) and satisfied tool/env requirements before publish.

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Discovery mode

In Discovery mode the Master Agent does not point at one fixed registration. You define Discovery filters; at runtime the platform finds registry agents that match.

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Set Discovery filters

  1. Configure filters parallel to the catalog sidebar.
  2. Click Save Filters — creates a Discovery Agent node with agent_node_type: "discovery" and discovery_filters.
  3. Open Configuration to select the API key (apikeyid) for runtime calls.
  4. Save the graph.
UI copy:
In Discovery Mode, the Master Agent will find and attach the agents automatically based on your filter criteria.
Only one Discovery registry agent node is allowed per Master Agent node. Adding a second shows Discovery Already Connected.
Discovery nodes skip per-tool configuration validation used in Browse mode — the filter set defines what may attach at runtime.

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Persisted node fields

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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.