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

With no annotations, the description carries the full transparency burden. It clearly implies a read-only operation ('Get') and comprehensively lists the returned fields (bio, counts, verification, linked accounts), which goes beyond the schema. It also specifies the 'exactly one' input constraint. It does not disclose rate limits or error behavior, but this is a simple read operation and the description provides solid behavioral context.

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?

Three tight sentences: first states the action and identifiers, second enumerates the returned fields, third gives the exclusivity constraint. No filler or repetition. Every sentence adds value and the structure is front-loaded.

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 single-profile read with three params and no output schema, the description is nearly complete: it covers inputs and outputs. It lacks only explicit error handling (e.g., user not found, multiple identifiers supplied) and any caveats about nested data or pagination, but the given information is sufficient for most agent invocations.

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 100% of parameters with good descriptions, so the baseline is 3. The description adds the crucial 'exactly one of username, user_id, or url' constraint, which is not captured in the schema's optional/required fields. This meaningful addition elevates the score to 4.

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 action ('Get the full profile for a single TikTok user') and specifies the resource and input identifiers (username, user_id, or URL). It also lists the key fields returned, which distinguishes it from sibling tools like tiktok_video_details or search_tiktok_users.

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 clear context: use this tool when you need a full profile for one known TikTok user, and you can provide one of three identifiers. However, it does not explicitly contrast with search_tiktok_users (e.g., 'use search to find users first') or mention when not to use this tool, so it stops short of a 5.

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