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

Annotations already declare readOnlyHint=true and openWorldHint=false; the description reinforces this with 'Pure computation, free,' telling the agent the call is offline, side-effect-free and costless. It adds genuine context rather than restating the hints, though it says nothing about behavior on malformed input.

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?

Two tight sentences: what it returns is front-loaded, and the secondary note about cost and locality is a short trailing clause. Nothing is wasted.

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 one-parameter pure function with no output schema, the description effectively enumerates the return categories, which is the main thing an agent needs. Only the accepted input formats and invalid-input behavior are left unstated.

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?

Schema description coverage is 0%, so the description must carry the load, and it only implies the single parameter is an address. It does not say whether IPv6 is accepted or whether CIDR notation is allowed -- a relevant ambiguity given the sibling bursia_cidr_info exists.

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?

States a specific verb (Classify) and resource (an IP address) and enumerates the exact labels returned: version plus public/private/loopback/link-local/reserved. That makes it clearly distinguishable from siblings like bursia_cidr_info or bursia_dns_records, though it does not name those alternatives.

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?

Usage is implied by the purpose -- reach for this when you need to categorize a single address -- but there is no explicit when-to-use, when-not-to-use, or pointer to bursia_cidr_info for subnet-level questions. The agent must infer the boundary itself.

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