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

With no annotations, the description carries the burden and does so well: it discloses the data source (recorded paid tiers), the failure behavior (it states plainly when tier prices are not recorded), and the modelling boundaries (per-seat pricing, usage charges and taxes are excluded). It does not describe the response shape, but no output schema exists so some ambiguity remains.

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 tight sentences, front-loaded with the core action, followed by data-source caveat and scope exclusions. Every sentence earns its place with no filler.

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 simple two-parameter read-only estimator, the description covers what is computed, from what source, how it behaves when data is missing, and what is out of scope. Only the return shape is left unstated, which is acceptable given no output schema.

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%, so both parameters are already documented. The description reinforces that months is a period and that pricing comes from paid tiers, but adds no format or constraint details beyond the schema's 1-60 range.

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 — the cost of one tool over a number of months — and identifies the data source (recorded paid tiers). It is clearly distinct from compare_tools or recommend_tool by implication, though no sibling is named explicitly.

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: reach for this when you want a single tool's cost over time rather than a comparison or recommendation. There is no explicit when-not guidance or named alternative, so the agent must infer that compare_tools handles multi-tool cases.

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