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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive. The description adds valuable behavioral context beyond those: caching for 12 hours, free cost, and the provider-availability semantics (which sources are on/off and why). It does not cover rate limits or quota, but the added context is substantial.

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 front-loaded with purpose and key output details, then defaults, then provider caveat, then use case. It is appropriately sized and every sentence contributes, though the middle sentence is slightly long with parenthetical nesting.

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?

Given the output schema exists and annotations cover safety, the description is nearly complete: it covers purpose, defaults, caching, cost, provider semantics, and recommended use. Only minor behavioral details (e.g., pagination or rate limits) are absent, which is acceptable for a read-only tool with an output schema.

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%, so each parameter is already documented in the schema. The description adds only the default behavior for niche/region from brand profile, which is also stated in the schema. No extra format or constraint details beyond the schema are provided.

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 specifies the resource (trending hashtags, sounds, creators, top posts) and the scope (niche, country) with concrete output fields (ranked, views, post counts). It is clear what the tool returns, though it does not explicitly name or differentiate against the sibling radar_ads 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?

Explicitly states the use case: 'Use it to pick a timely topic for hooks_generate or a sound/hashtag for a post.' It also names the fallback behavior ('an empty list means no source covers it, do not invent trends') and the default source of niche/market, leaving little to inference.

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