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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), but the description adds real behavioral context: stale saved offers remain listed with stale flags and source timestamps, and results carry citations, coverage and pagination. That is information the annotations cannot supply.

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 purpose and default ordering, then the stale/return/pagination caveats, then the exclusion. Four compact sentences with no filler, though some sentences bundle several ideas (stale flags plus timestamps plus pagination) that could be split.

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 17-parameter tool with no output schema and no required parameters, the description adequately covers what comes back (prices, citation links, timestamps, coverage, pagination) plus the stale-data lifecycle and the availability exclusion. Auth/registrar-set details live in the schema, so nothing critical is missing.

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 the 17 parameters are documented in detail (enums, patterns, defaults), so the schema carries the parameter burden. The description only echoes the default sort and the returned fields, adding no syntax or format detail beyond what the schema already states — the baseline 3.

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 and resource ('Compare standard prices', 'registrar offers'), the default ranking metric, and an explicit boundary ('Does not check exact-name availability') that separates it from the check_availability siblings. An agent can identify this as the price-comparison tool without opening the schema.

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 clear context for use (compare prices across domain extensions and registrars, renewal-oriented by default) and one explicit exclusion routing away from availability checks. It does not, however, say when to prefer this over neighboring siblings such as get_tld_prices or estimate_cost, so the routing guidance is partial.

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