Price estimate for one trim and year

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so safety behavior is covered. The description adds useful behavioral detail beyond annotations: the range is what Hamrah Mechanic pays or advises in Toman, and monthly_change_percent is only available for some trims.

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 description is three concise sentences and front-loads the core purpose. Every sentence adds useful information about output meaning, eligibility, or the relevant alternative tool.

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 lookup with no output schema, the description explains the returned range, units, partial availability of monthly change, and the alternative for history. An agent has enough information to invoke it 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 description coverage is 100%, so both parameters are already well documented, including year format and type_id provenance. The description adds limited meaning beyond the schema, mainly repeating that type_id and year should come from hm_prices rows.

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?

The description states a specific verb and resource: get the market price range and recent monthly change for one trim in one model year. It names the returned fields (priceDown, priceUp, monthly_change_percent) and distinguishes the tool from hm_price_history.

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?

It gives clear context for use: supply a type_id and year from hm_prices rows. It also explicitly routes monthly price history requests to hm_price_history, though it does not discuss other possible alternatives such as hm_price_list.

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