cnc-mcp

Get Topology Summary

cnc_get_topology_summary

Read-onlyIdempotent

Get CNC topology totals and state breakdowns in one read-only call. Use it first to check if the topology is populated before drilling into nodes or links.

Instructions

Summarize the CNC topology: node/link totals and state breakdowns.

Read-only. Combines three topology-service calls (init, nodes/summary, edges/summary) into one answer. Use it first to learn whether the topology is populated at all (an empty topology with a populated inventory usually means no reachable SR-PCE provider), then drill in with cnc_get_topology, cnc_list_topology_nodes or cnc_list_topology_links.

Returns: str: JSON: {"total_nodes": int, "unmapped_nodes": int, "max_logical_nodes": int, "reachability": {"CONN_STATE_REACHABLE": 5, ...}, "link_state": {"Up": 1, "Degraded": 0, "Down": 0}, "node_breakdowns": {: {: }, ...}, "link_breakdowns": {: {: }, ...}} unmapped_nodes counts nodes with no geographic location (they render on the logical map only). node_breakdowns carries every section the platform returned (e.g. device family) keyed by type. Counts are null and breakdowns empty when the platform returns an empty body (fresh, unpopulated topology). On failure: "Error: ". An HTTP 500 "Internal Server Error" from /v1/topology-service/... means the service rejected the request body (mapType/viewId/params) — deterministic, do NOT retry. (It is not the inventory's "NATS request failed" signal.)

Input Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 12, 2026

TDQS

A4.8/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover read-only/idempotent, but the description adds substantial context beyond them: it discloses that three topology-service calls are combined, explains empty-body semantics (null counts, empty breakdowns), the failure format, and a critical non-retry rule for HTTP 500 body rejections, distinguishing it from the inventory's NATS failure signal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the one-line purpose, then usage guidance, then a structured Returns block. The return-shape transcription borders on redundant given an output schema exists, but the semantic annotations attached to it (unmapped_nodes meaning, empty-body behavior) justify most of the length.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Covers purpose, ordering guidance, alternative tools, return semantics, empty-topology interpretation, and error handling with a non-retry directive. Nothing an agent needs to call this zero-parameter tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes zero parameters, so there is nothing to disambiguate; baseline for 0 params is 4. The description correctly implies no filtering input is required.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource ('Summarize the CNC topology') plus the exact scope (node/link totals and state breakdowns), and explicitly names the sibling tools used for drilling in (cnc_get_topology, cnc_list_topology_nodes, cnc_list_topology_links). An agent can distinguish this from the drill-in siblings without reading any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicit ordering guidance: 'Use it first to learn whether the topology is populated at all,' with a concrete diagnostic rule (empty topology + populated inventory ⇒ no reachable SR-PCE provider), then routes to the appropriate drill-in alternatives. Both when-to-use and when-to-use-something-else are covered.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.