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

Annotations already cover readOnlyHint=true, openWorldHint=true, and destructiveHint=false, so the safety profile is clear. The description adds useful behavioral context beyond annotations: it discloses the cost ('Spends about a credit'), the ranking behavior ('ranked by plays'), and the output structure ('Returns compact JSON {desc, author, handle, plays, likes, link, cover}'). This enriches the agent's understanding without contradicting annotations.

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 two sentences, front-loaded with the core action and caveat, then provides the purpose, output shape, ranking, alternative, and cost in a compact manner. Every sentence adds value with no fluff, and the key distinguishing info (no ad library, organic) appears first.

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 simplicity of the tool (2 parameters, no output schema, but with a descriptive output summary), the description covers everything an agent needs: what it does, what it returns, how it's ranked, when to use an alternative, and the credit cost. The absence of an output schema is compensated by the explicit return format in the description.

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 both parameters (query and limit) are already well-documented in the schema with clear descriptions and defaults. The tool description does not add significant meaning beyond the schema for these parameters—it restates the general keyword nature and the limit range is already in the schema. Thus the baseline of 3 applies.

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 specific action ('Organic TikTok keyword search'), the resource (TikTok organic content), and the purpose ('mine for hooks/trends/remixable creative'). It distinguishes itself from an ad library and from sibling search tools by explicitly naming the platform and the organic nature, and it specifies the return format, making it unambiguous which tool to use.

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 explicit guidance for an alternative: 'Use research_ads for open-ended research.' This clarifies a key distinction. However, it does not mention other search tools (e.g., search_instagram, search_youtube) or provide comprehensive when-not-to-use guidance, so it earns a 4 rather than a 5.

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