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

Annotations already declare read-only, idempotent, non-destructive behavior, so safety is covered. The description goes well beyond that: it discloses the comparison semantics (IPv4 and IPv6 compared separately), output shape (normalized subnets, exact overlapCount, up to 200 input-index pairs), truncation metadata (omittedOverlaps/truncated), and a prompt-injection caveat treating returned evidence as untrusted data — genuinely useful behavioral context.

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?

Front-loaded with the core action, then output guarantees, then the security caveat. Dense but every clause carries information; the only mild cost is the long enumerative middle clause, though it is justifiable given there is no output schema.

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 compensates thoroughly by describing returned fields, truncation metadata, and IPv4/IPv6 separation. Combined with annotations covering safety, an agent has everything needed to call and interpret this tool correctly.

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?

One parameter with low declared schema coverage, so the description carries much of the burden: it specifies the accepted format family (IPv4/IPv6) and the cardinality cap of 100, which aligns with the schema's maxItems. It does not add per-item format or error-handling detail beyond the schema's own example.

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 ('Detect') and resource ('overlapping ranges among up to 100 IPv4/IPv6 CIDRs'), with scope limits baked in. An agent can immediately tell this is an overlap-detection tool, distinct from inspect_subnet (single subnet inspection) and plan_subnets (allocation).

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 — call it when you need to find overlaps in a set of CIDRs — but there is no explicit when-to-use guidance, no conditions selecting it over inspect_subnet or plan_subnets, and no prerequisites. Minimum viable routing information.

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