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

Annotations already declare read-only, idempotent, non-destructive, non-open-world behavior. The description adds value beyond those by specifying the return payload ('short answer, check date and URL') and the subject coverage, though it does not discuss rate limits or failure modes.

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?

Front-loaded with 'BRAZIL' and the core action, then a compact dash list of coverage topics. It is a single sentence and every element supports retrieval, though the topic list is long.

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 one-parameter guide lookup with no output schema, the description supplies the missing return fields and scope. It is sufficient to call correctly, with only minor absence of no-result behavior.

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% and the single 'query' parameter is already documented with examples. The description's topic list contextualizes query scope but does not add syntax or format rules beyond the schema.

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 ('Finds') and resource ('Payotte guide answering a question about a home in Brazil'), and the 'BRAZIL' prefix distinguishes it from sibling guide_* tools for other markets. The topic list further clarifies scope.

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?

Provides only implicit guidance: use when you need a guide answer about a home in Brazil. It does not name alternatives (e.g., capital_gains_tax_br, purchase_costs_br) or state when not to use it, so the agent must infer the routing.

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