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

Annotations already establish a safe read-only, closed-world browse, so the bar is lower. The description adds genuine scope context beyond the annotations: it notes webtoon coverage (Korean manhwa, Chinese manhua, WEBTOON/Tapas originals) and that platform accepts both streaming and reading services.

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 core capability, followed by the list_genres pointer and then examples. The example list is somewhat long and repeats coverage already implied ('best action manhwa' after webtoon coverage), but nothing is confusing or buried.

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 10-parameter browse tool with no output schema and read-only annotations, the description covers most of what an agent needs to invoke it. The remaining hole is the undocumented interaction between media_type and format plus the 25-result cap, which could cause incorrect calls but is a narrow gap.

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 description coverage is only 40%, so the description must compensate, and it does partially: it explains genres require slugs from list_genres, that platform covers both streaming and reading services, and what webtoon_only means. However it never explains media_type (anime vs manga), its relationship to format, or the limit/pagination cap of 25, leaving several parameters ambiguous.

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 states a specific verb ('Browse the catalog') and enumerates the exact filter axes (genre, year, status, format, service, sort order), making scope unambiguous. It also names the sibling helper list_genres for genre slugs, so the agent can route without opening a schema.

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?

Concrete example intents ('best romance anime', 'what anime is on Netflix', 'romance webtoons on WEBTOON') clearly signal when to reach for this tool, and it points to list_genres for slug lookup. It stops short of an explicit contrast such as 'use search_titles when you have a keyword', so the boundary with the sibling search tool is left to inference.

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