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

Goes well beyond the annotations: discloses that data comes from a committed snapshot (so calls answer instantly), that the snapshot date is included in the answer, and that pricing is $0.01/call with 25 free and failed calls free — which also explains why idempotentHint is false ('repeats are not free'). This is exactly the kind of context annotations cannot carry.

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 the resource and payload, then freshness, then pricing. Dense but mostly earned; the pricing/auth sentence is longer than needed but conveys genuinely useful invocation constraints.

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, the description carries the return-shape burden and does so: three metrics, units, ordering, and the snapshot date in the answer. Source/licensing (World Bank, CC BY 4.0) and cost model round out everything an agent needs to call it correctly.

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%, so baseline is 3; the description adds meaning the schema lacks by stating results are ordered newest-year-first and that country accepts either ISO code form (SE, SWE) or English name, with a worked example (country=SE).

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 the resource (GDP) plus the exact three metrics returned (current US$, real growth %, per capita) and the 1-10 year window, so the agent knows precisely what data comes back. The resource is naturally distinct from siblings like econ_inflation and econ_population, though no sibling is named explicitly to sharpen 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?

'Use for country comparisons, market sizing and macro context' gives concrete usage contexts. It stops short of naming alternatives or exclusions (e.g., when to prefer econ_inflation for price levels), so it's clear but not fully routing.

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