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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, and the description aligns with them — no contradiction. The description adds value beyond annotations by disclosing that results are English-only, distinguishing full vs. short effect text, and revealing the hidden-ability flag/slot structure in the returned ability record. It doesn't cover error behavior, but the annotation safety profile lowers that burden.

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?

Two tightly written sentences with zero waste: the first packs purpose plus the full return-value inventory, the second adds the cross-tool sourcing hint. The most decision-relevant information (what it returns, how to address it) is front-loaded.

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 an output schema present to cover return shapes, the description supplies everything an agent needs to select and call the tool: the lookup identifier format, the source of valid names, and the contents of the response. For a single-parameter read-only API tool with full annotation coverage, nothing material 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?

Schema coverage is 100%, so the parameter format (lowercase hyphenated name or numeric ID) is already documented. The description adds real value by explaining where valid identifiers come from (the abilities array of pokeapi_get_pokemon) and confirming both lookup routes (by name or numeric ID), which goes beyond the bare schema baseline of 3.

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 uses a specific verb+resource ('Get ability details') and enumerates the exact data returned: full and short English effect text, generation introduced, and the Pokémon list with hidden-ability flag and slot. Among siblings that target distinct resources (items, moves, natures, Pokémon, type matchups), the purpose is unmistakable.

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 provides the key workflow linkage: 'Ability names are returned by pokeapi_get_pokemon in the abilities array,' telling an agent exactly where to source valid identifiers before calling this tool. It lacks explicit when-not-to-use phrasing or named exclusions, but the resource distinction among siblings makes the usage context clear.

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