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

Annotations already communicate read-only, idempotent, non-destructive behavior, so the description does not need to repeat that. It adds useful behavioral context beyond annotations: the list is fixed at 50 economies, each returned entry has a code and name, and several non-obvious code mappings (PRC, INO, BAN) are highlighted. It does not discuss ordering or pagination, but the presence of an output schema and simple list shape reduces the need.

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?

The first sentence front-loads the core action and scope, and each following sentence earns its place: return shape, downstream use, key codes, and the alias caveat. Despite the helpful examples, there is no redundant or filler content.

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, read-only reference list with a fully documented single optional parameter and an output schema, the description covers everything an agent needs: what is returned, how many items, how the names relate to downstream data queries, and the data source. Nothing critical is missing.

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?

The input schema already fully documents the single optional search parameter, so the baseline is 3. The description adds value by providing concrete high-value code examples and explicit alias warnings (China is PRC not CHN, Indonesia is INO, Bangladesh is BAN) that help an agent form correct search values beyond the schema's own examples.

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?

The description opens with a specific verb and resource: 'List the 50 ADB member economy codes used to query the Key Indicators Database.' It clearly states what is returned (3-letter code and full name) and distinguishes this reference tool from the adbkidb.explore.dataflows and adbkidb.explore.indicators siblings by framing it as the code source for adbkidb.data queries.

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?

The description gives clear context for when this tool is useful: it supplies the economy_codes consumed by adbkidb.data queries. It does not explicitly name alternatives or say 'use this instead of explore.dataflows/indicators,' but the reference-list purpose is unmistakable and the downstream usage is explicitly stated.

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