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

The description adds behavioral details beyond annotations: results are ordered by increasing median price, and top_n has a default of 5 with a max of 10. Annotations already declare read-only and idempotent, so the description enhances operational understanding. No contradiction exists.

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 a single compact sentence plus a parenthetical, covering purpose, usage, and operational limits. Every phrase earns its place, with no filler or redundancy.

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 tool with 2 simple parameters and no output schema, the description adequately conveys what it does, how results are sorted, and usage intent. It does not detail the return format, but the phrase 'por preço mediano crescente' implies a list of states with prices. This is sufficient for the tool's simplicity.

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 0%, so the description must compensate. It partially explains top_n (default 5, max 10) but does not explicitly describe car_id, leaving its meaning to inference from 'este modelo' (this model). This is a gap for a required parameter.

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 clearly states the tool returns states (UF) where the car model is cheapest now, sorted by increasing median price. This specifies a concrete resource and action, and distinguishes it from siblings like get_market_stats or get_avg_days_to_sell which address different market aspects.

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 provides an explicit usage cue: 'Use para "onde é mais barato comprar"' (Use for 'where is cheapest to buy'), which tells the agent when to select this tool. However, it does not mention alternatives or explicitly say when not to use it, so it lacks that exclusionary guidance.

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