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

Annotations already declare readOnly, idempotent, non-destructive, so the safety profile is covered; the description adds genuine value by clarifying the operation is purely observational and that output shape is OS-dependent — a real behavioral caveat for the agent. It doesn't mention permissions/privilege requirements or failure modes, which keeps it below 5.

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

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

Three sentences, front-loaded with the trigger condition and scope, then purpose, then the negative boundary. No redundant restatement of the title.

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

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

For a single-parameter read-only inspection tool with an output schema and full annotation coverage, the description supplies everything needed: scope, OS variability of results, and confirmation of non-mutation.

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

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

Only one parameter and schema coverage is 100% — the device field already documents that it is a ReMCP device id from list_devices. The description adds nothing beyond the schema, so the baseline 3 applies.

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

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

Specific verb+resource: 'inspect the local OS routing table on a paired computer', with the concrete contents enumerated (default gateway, destination networks, next hops, route metrics). This is clearly distinct from sibling tools like network_interfaces, network_listeners, network_summary and network_test.

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

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

Gives explicit use conditions ('when the user asks to inspect the routing table', 'diagnose routing and reachability issues') plus clear exclusions ('does not add routes, send traffic or change network settings'). It stops short of naming a sibling to route to for reachability testing (e.g. network_test), so not quite a 5.

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