Query audited ANP fuel prices for gasoline, ethanol, diesel S10, and CNG by Brazilian state or city to compare station costs.
Queries real-time audited fuel prices (Gasoline, Ethanol, Diesel S10, CNG) from Brazil ANP across 4,750+ stations in all 27 states.
| Name | Required | Description | Default |
|---|---|---|---|
| uf | Yes | Brazilian state code (e.g., 'sp', 'rj', 'mg', 'ba', 'pr', 'rs', 'df') | |
| cidade | No | City name or slug (e.g., 'sao-paulo', 'cabo-frio') |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden. It does add useful provenance context (ANP, audited, real-time, coverage figures), and 'Queries' implies a read-only operation, but it says nothing about rate limits, auth requirements, pagination, or return shape.
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?
A single dense sentence with zero filler; the core capability and data scope are front-loaded. Nothing in it is redundant or padded.
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 query with full schema coverage and no output schema, the description covers what an agent needs to know before calling it: what data, from where, and how fresh. Only return-format details are absent, and there is no output schema demanding them.
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 'uf' and 'cidade' are already documented with examples in the schema. The description adds no parameter-level meaning beyond that, making the baseline 3 appropriate.
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 (Queries) and resource (real-time audited fuel prices) plus the data source (ANP) and scope (4,750+ stations, 27 states). An agent can distinguish this from brazil_grocery_basket and cost_of_living_brazil, though the description never explicitly contrasts itself with those siblings.
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 only implied: the description makes clear you call this when you need Brazilian fuel price data, but it names no alternatives, no when-not-to-use conditions, and no prerequisites. No sibling routing guidance is offered.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.