# add_library_symbol_property

Add or update a custom property (Manufacturer, MPN, LCSC, etc.) on a symbol definition in the lib_symbols section. This makes the property available to all instances of that symbol in the schematic.

Agent View of the PolicyLayer registry record for `add_library_symbol_property`. HTML page: https://policylayer.com/tools/mixelpixx-kicad-mcp-server/add-library-symbol-property

## Facts

- Tool: `add_library_symbol_property`
- Server: KiCAD-MCP-Server (`mixelpixx/kicad-mcp-server`) — https://policylayer.com/tools/mixelpixx-kicad-mcp-server.md
- Homepage: https://github.com/mixelpixx/KiCAD-MCP-Server
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "add_library_symbol_property",
    "arguments": {}
  }
}
```

## Why add_library_symbol_property is rated Medium

This tool creates or modifies metadata (properties like Manufacturer, MPN, LCSC) on symbol definitions. It is reversible—properties can be updated or removed—and does not delete data or execute arbitrary code. The modification affects the schematic library definitions, making it a Write operation.

From the tool's own definition: "Tool description states it will 'Add or update a custom property' on a symbol definition, which modifies the lib_symbols section and affects all instances of that symbol in the schematic."

## Use case

AI agents use add_library_symbol_property to create or update resources in KiCAD-MCP-Server, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your KiCAD-MCP-Server environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches KiCAD-MCP-Server:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_library_symbol_property": {
      "limits": [
        {
          "counter": "add_library_symbol_property_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on KiCAD-MCP-Server (230)

- `clear_board_outline` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/clear-board-outline.md
- `delete_component` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-component.md
- `delete_graphic` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-graphic.md
- `delete_schematic_component` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-schematic-component.md
- `delete_schematic_net_label` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-schematic-net-label.md
- `delete_schematic_wire` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-schematic-wire.md
- `delete_symbol` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-symbol.md
- `delete_trace` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/delete-trace.md
- `discard_or_reload` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/discard-or-reload.md
- `remove_hierarchical_sheet` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/remove-hierarchical-sheet.md
- `remove_library_table_entry` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/remove-library-table-entry.md
- `remove_schematic_component_property` — Destructive — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/remove-schematic-component-property.md
- `autoroute` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/autoroute.md
- `export_3d_cli` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/export-3d-cli.md
- `export_drill` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/export-drill.md
- `launch_kicad_ui` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/launch-kicad-ui.md
- `refill_zones` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/refill-zones.md
- `run_drc` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/run-drc.md
- `run_erc` — Execute — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/run-erc.md
- `batch_list_symbol_pins` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/batch-list-symbol-pins.md
- `check_clearance` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/check-clearance.md
- `check_courtyard_overlaps` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/check-courtyard-overlaps.md
- `check_freerouting` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/check-freerouting.md
- `check_kicad_ui` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/check-kicad-ui.md
- `check_placement_clearance` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/check-placement-clearance.md
- `download_registry_part` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/download-registry-part.md
- `estimate_airwire_lengths` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/estimate-airwire-lengths.md
- `export_bom` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/export-bom.md
- `export_ipc2581` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/export-ipc2581.md
- `export_ipcd356` — Read — https://policylayer.com/tools/mixelpixx-kicad-mcp-server/export-ipcd356.md
- …and 200 more: https://policylayer.com/tools/mixelpixx-kicad-mcp-server.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=mixelpixx-kicad-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/mixelpixx-kicad-mcp-server