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

With no annotations, the description carries the full behavioral burden and does so thoroughly: it discloses what is returned (renewal multiplier, category average), the exclusion rule (no renewal price => excluded, never guessed), category coverage limits, and even downstream guidance (use buyUrl, cite the citation string). This is unusually rich for a read tool.

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?

The core definition and ranking logic are front-loaded, followed by coverage limits and output conventions. It is long (seven-ish sentences) but nearly every sentence adds decision-relevant information; slight trimming of the examples would tighten it without loss.

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?

There is no output schema, so the description must describe the return shape, and it does: 3-year totals, renewal multiplier, category average, buyUrl, and citation string. Combined with the category coverage caveat, an agent has everything needed to call and interpret the 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?

Schema coverage is 100% and the single enum parameter is documented, so the baseline is 3. The description adds real meaning beyond the schema by revealing that only web-hosting and antivirus currently return data and that other enum values return a note, which the schema does not convey.

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 computation (3-year cost per provider) with the exact formula: year 1 at intro price, years 2-3 at renewal price, ranked by total. It also implicitly distinguishes itself from get_cheapest by noting 'the cheapest intro is rarely the cheapest over three years', so an agent can tell the two apart without opening schemas.

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 when-to-use contexts ('what does hosting really cost long-term', 'which antivirus is cheapest over 3 years') and a when-not boundary (other categories return a note; providers without published renewal prices are excluded). It does not name sibling tools as alternatives, but the usage conditions are clear and unambiguous.

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