List elements (objects) in the translated Navisworks model with their objectid, name, externalId, and full property bag, optionally filtered by a case-insensitive keyword matched against name and Category. When to use: when answering "how many VAV boxes are on Level 3?", "list every steel column ...
Risk signalsBulk/mass operation — affects multiple targets
Part of the Navisworks MCP server.
Free to start. No card required.
AI agents call nwd_list_objects to retrieve information from Navisworks MCP without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though nwd_list_objects only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"nwd_list_objects": {}
}
}See the full Navisworks MCP policy for all 5 tools.
These attack patterns abuse exactly the kind of access nwd_list_objects gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
List elements (objects) in the translated Navisworks model with their objectid, name, externalId, and full property bag, optionally filtered by a case-insensitive keyword matched against name and Category. When to use: when answering "how many VAV boxes are on Level 3?", "list every steel column with mark C-*", or any per-element question; when dumping a quick takeoff of a discipline before handing off to an estimator; when an agent needs externalIds to cross-reference with a Revit or ACC issue. When NOT to use: not for clash detection (use nwd_get_clashes); not for camera/viewpoint data (use nwd_get_viewpoints); not for full-model exports — results are capped at 100 objects per call, so use the filter argument to narrow. APS scopes required: viewables:read data:read. Rate limits: APS default ~50 req/min; two Model Derivative calls per invocation (metadata guid + properties). Properties endpoint may 202 "isProcessing" on first call after translation — the worker retries once after 3s. For very large models the properties payload can be tens of MB; expect higher latency. Errors: 401 token (retry); 403 scope (report); 404 URN not found; 409 N/A; 422 property index not yet built — returns object_count:0 (poll via nwd_export_report); 429 rate limit (backoff); 5xx APS upstream (retry once). If property collection is legitimately empty the tool returns success with object_count:0 and an empty objects array. Side effects: none. Pure read. Idempotent. Logs usage to D1 usage_log. Response includes a note field when the unfiltered collection exceeds the 100-object cap.. It is categorised as a Read tool in the Navisworks MCP MCP Server, which means it retrieves data without modifying state.
Register the Navisworks MCP server in PolicyLayer and add a rule for nwd_list_objects: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Navisworks MCP. Nothing to install.
nwd_list_objects is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the nwd_list_objects rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for nwd_list_objects. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
nwd_list_objects is provided by the Navisworks MCP server (https://navisworks-mcp.itmartin24.workers.dev/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 Navisworks MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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