# list_block_types List every block type understood by Card Builder. Agent View of the PolicyLayer registry record for `list_block_types`. HTML page: https://policylayer.com/tools/fistacho-ha-nexus-agent/list-block-types ## Facts - Tool: `list_block_types` - Server: Ha Nexus Agent (`fistacho/ha-nexus-agent`) — https://policylayer.com/tools/fistacho-ha-nexus-agent.md - Homepage: https://github.com/Fistacho/ha-nexus-agent - Risk category: Read (Low risk) - Registry record: grade F, identity unverified - Server rate-limited: no - Parameters: 0 - Recommended policy verdict: Allowed ## Example call (MCP tools/call, JSON-RPC 2.0) ```json { "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": { "name": "list_block_types", "arguments": {} } } ``` ## Why list_block_types is rated Low This tool retrieves metadata about available block types in Home Assistant's Card Builder system. It performs information retrieval only, with no capability to modify, delete, execute operations, or affect system state. The blast radius of misuse is negligible—an agent could only query what block types exist, not modify the home automation system itself. From the tool's own definition: "Tool name 'list_block_types' with description 'List every block type understood by Card Builder' indicates a query/retrieval operation with no side effects." Risk signals: Bulk/mass operation — affects multiple targets ## Use case AI agents call list_block_types to retrieve information from Ha Nexus Agent without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere. ## Recommended policy (PolicyLayer) Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Ha Nexus Agent: ```json { "version": "1", "default": "deny", "tools": { "list_block_types": {} } } ``` ## Other tools on Ha Nexus Agent (275) - `abort_config_flow` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/abort-config-flow.md - `abort_options_flow` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/abort-options-flow.md - `delete_area` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-area.md - `delete_automation` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-automation.md - `delete_backup` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-backup.md - `delete_blueprint` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-blueprint.md - `delete_card` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-card.md - `delete_category` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-category.md - `delete_config_file` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-config-file.md - `delete_css_custom_property` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-css-custom-property.md - `delete_event` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-event.md - `delete_label` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-label.md - `delete_media` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-media.md - `delete_pipeline` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-pipeline.md - `delete_script` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-script.md - `delete_style_preset` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-style-preset.md - `delete_theme` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-theme.md - `delete_zone` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/delete-zone.md - `git_rollback_file` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/git-rollback-file.md - `git_rollback_to_commit` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/git-rollback-to-commit.md - `notify_persistent_dismiss` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/notify-persistent-dismiss.md - `notify_persistent_dismiss_all` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/notify-persistent-dismiss-all.md - `remove_device` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-device.md - `remove_energy_source` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-energy-source.md - `remove_integration` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-integration.md - `remove_item` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/remove-item.md - `restore_backup` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/restore-backup.md - `stop_ha` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/stop-ha.md - `uninstall_addon` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/uninstall-addon.md - `uninstall_hacs_repository` — Destructive — https://policylayer.com/tools/fistacho-ha-nexus-agent/uninstall-hacs-repository.md - …and 245 more: https://policylayer.com/tools/fistacho-ha-nexus-agent.md ## For agents This record is a snapshot. Live verdicts and the full registry: - Check every server in your MCP config at once: `npx -y policylayer stack` - Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md) - Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events` --- Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=fistacho-ha-nexus-agent · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/fistacho-ha-nexus-agent