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

Annotations already declare read-only, idempotent, open-world behavior, but the description adds real context beyond them: the returned fields, earliest comparison values, source provenance, the caveat that reporting years vary by indicator, and a $0.01 cost that affects invocation decisions. It still omits coverage breadth, such as how many indicators or goals are returned.

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?

One front-loaded sentence with no filler; the payload enumeration is dense but each element informs the agent what it will receive. The cost clause and year-variance caveat are appended efficiently.

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?

With no output schema, describing the return shape (series, values, years, units, comparisons, provenance) is exactly what the description should do, and it adds the two facts an agent most needs before calling: variable reporting years and a per-call cost.

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 coverage is 100% and both parameters (code, goal) are documented in the schema with pattern and range. The description adds no additional meaning about how code or goal affect the response, so baseline 3 applies.

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 and resource ('Return latest reported headline UN SDG indicators for a country') with the content scope spelled out. It does not name or distinguish itself from plausible siblings such as get_country_report or get_economy_report, so an agent must infer the boundary.

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 by phrases like 'latest reported headline' indicators; there is no explicit when-to-use or when-not-to-use statement and no routing to alternative tools.

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