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

With no annotations at all, the description carries the behavioral burden. It clearly discloses cost (1 credit), the no-charge policy for empty results and failures, and cache behavior (free 24h cache hit, default always fresh). This is strong behavioral context, though it stops short of richer execution details like rate limits or retry behavior.

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?

Four short sentences, each earning its place: what the tool returns, cost, failure charging policy, and cache usage. The core purpose is front-loaded and there is no filler or repetition beyond what is necessary for context.

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 two-parameter read tool with no output schema or annotations, the description conveys the essential information: input expected, output shape, pricing, failure charging behavior, and cache option. It does not detail what exactly the 'counts' mean and there is no output schema, but the definition is sufficiently complete for a capable agent to call it correctly.

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?

The schema already covers both parameters at 100% and describes URL format/platform matching and cache semantics in detail. The description adds little beyond the schema, restating the cache behavior in equivalent terms. Baseline 3 is appropriate because the schema does the heavy lifting.

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 has a specific verb ('Fetch'), a specific resource ('Kwai profile'), and a concrete list of returned data (display name, bio, counts, verification as structured JSON). It clearly distinguishes from siblings like kwai_post and kwai_user_posts which are post-oriented endpoints.

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 'use this for Kwai profile metadata' and gives operational guidance around credits and caching, but it does not explicitly tell the agent when to choose this tool over related siblings such as kwai_user_posts or kwai_post. Selection guidance is inferred from the name and returned fields rather than stated directly.

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