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

Annotations already provide readOnlyHint, destructiveHint, idempotentHint, openWorldHint. Description adds license (ODbL) and parameter constraint (last N, max 500). No additional behavioral details like authentication, rate limits, or data freshness. Acceptable given annotation coverage.

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?

Single sentence with key info: source, series number, license, parameter hint. No wasted words, but could be slightly more structured (e.g., bullet points) for readability.

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?

Simple tool with one parameter and existing annotations. Description covers source, series, license, and parameter limits. Output schema exists, so no need to document return format. Adequate for an agent.

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 covers 100% of the single parameter last_n, including default, max, and interpretation for monthly series. Description reiterates 'last N observations' but does not add new meaning beyond 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?

Description clearly states 'Brazilian IPCA monthly inflation rate (series 433) — last N observations from BCB SGS', specifying verb (get), resource (IPCA inflation rate), source, and series number. Distinct from siblings like SELIC, CDI, etc.

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?

No explicit when-to-use vs alternatives, but the tool name and description imply it's for IPCA inflation data. Given distinct sibling tools, an agent can infer usage from the domain, but no guidance on when not to use or when to prefer other tools.

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