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

With annotations already declaring readOnlyHint, openWorldHint, and idempotentHint, the description adds valuable behavioral context: it is not cached, each call returns a fresh set, and pagination is supported via repeated calls. This goes beyond the annotations and helps the agent understand call semantics.

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 description is a single, information-dense sentence. It front-loads the purpose and immediately distinguishes the feed from cached/personalised alternatives, then notes pagination. Every clause earns its place with no redundancy.

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 tool with two optional parameters, no output schema, and annotations covering read-only/idempotence, the description provides the essential context: freshness, non-caching, and pagination. It does not detail the compact response structure, but that is minor for a trending feed.

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 100% for both parameters (count and expand), so the schema fully documents them. The tool description adds no additional parameter context beyond what the schema provides, which meets the baseline for high coverage.

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 clearly states the tool returns TikTok's Explore/Discover feed, i.e., trending content. It adds 'what is trending now' to specify the resource. It differentiates by noting it's not personalised, which separates it from search tools, but it does not name a specific sibling tool.

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 implies usage: use when you want a fresh, non-personalised set of trending videos, and call again for more. It does not explicitly state when not to use it or compare to alternatives, leaving the agent to infer the decision.

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