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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, and the description still adds real value: deterministic 'largest blocks first' ordering, the exact outputs returned (allocations, exact remaining addresses, explicit insufficient-capacity results), and a prompt-injection warning that returned evidence is untrusted data. It does not contradict any annotation, since allocation planning is a pure read.

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 short sentences, front-loaded with the action and scope, then behavior, then the untrusted-data caveat. No filler or repetition of schema fields.

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?

With no output schema, the description usefully enumerates the return payload (allocations, remaining addresses, insufficient-capacity results), which is what an agent most needs. It is slightly thin on ordering guarantees under conflicting requests and on how partial failures are reported alongside successes.

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 coverage is only 50% (the nested label/prefix fields are undocumented in the schema), and the description compensates by explaining that requests are 'labeled prefix requests' and that the parent is an IPv4/IPv6 CIDR block. It still does not clarify that 'prefix' is a prefix length in bits or the meaning of 'label' as an identifier, leaving a small gap.

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?

The description gives a specific verb and resource: 'Allocate up to 100 labeled prefix requests within an IPv4/IPv6 parent.' The scope (up to 100, IPv4/IPv6, parent-contained) is concrete, and 'allocate' is clearly distinguishable from the sibling verbs 'check_cidr_overlap' and 'inspect_subnet'.

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 operation itself (planning multi-prefix allocations inside a parent), but the description never states when to prefer this over check_cidr_overlap or inspect_subnet, nor any when-not condition. The agent must infer the routing from the verb alone.

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