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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behaviour, so the safety profile is covered. The description adds real behavioural context beyond that: default ordering by lowest ongoing price, a last-updated date on each plan, a 10-result ceiling, and the fact that paging is capped at the first 50 matches. The pagination cap partially duplicates the offset schema text, which keeps this from a 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?

Four sentences, each carrying information: scope, filterable dimensions, ordering/return behaviour, and the list_providers routing hint. Front-loaded with the purpose, and the closing routing sentence is actionable rather than filler, though the filter enumeration is somewhat redundant against the 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 an output schema present, an extensive annotated parameter set, and read-only annotations, the description need only supply scope, ordering, and paging limits — all of which it does. The remaining gap is cross-sibling positioning against compare_plans and get_plan, which an agent must infer.

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 100% and 7 parameters carry enums with documented semantics, so the schema does the heavy lifting. The description's 'filter by price, included data, network, speed tier, contract and features' is a restatement of parameters already fully documented, adding no syntax, defaults, or interaction rules of its own.

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 (Search) and a precisely scoped resource (current Australian mobile, prepaid, mobile broadband and nbn home internet plans from Wireless Choices), and enumerates the filterable dimensions. An agent can tell at a glance this is the catalogue-search tool rather than a detail or comparison tool.

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 conditional routing to list_providers ('Use list_providers first if you are unsure which providers exist') and implies the filtering conditions under which the tool applies. It does not, however, say when to prefer compare_plans or get_plan over this search, so the sibling routing is only partial.

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