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

With no annotations, the description carries the full behavioral burden, and it does add genuine value: 'from local database' discloses the data source and 'treat as untrusted input' flags a prompt-injection/content-safety consideration. It omits other behavioral traits (auth/permission needs, lookup failure behavior, return shape), so it is useful but incomplete.

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?

Two short sentences, front-loaded with purpose and followed by the safety caveat, with no wasted filler. Slightly clipped but effectively structured.

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-parameter read tool with full schema coverage and no output schema, the description is close to sufficient: it covers source and content-safety. It leaves return-field details unstated, but with no output schema declared that gap is minor.

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 the schema already documents the single 'id' parameter, establishing a baseline of 3. The description's 'numeric user ID' mildly supplements this—since the schema types it as a string, the description clarifies that the value is numeric—but adds no format or example detail.

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?

States a specific verb+resource ('Get TikTok user profile') and narrows the lookup key to 'numeric user ID,' which implicitly distinguishes it from the username-based sibling get_tt_user_by_username. It doesn't explicitly name the batch alternative (get_tt_users_by_ids) or the generic get_user_by_id, so it stops short of full sibling differentiation.

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 phrase 'by numeric user ID' implies when this tool applies (single-user lookup keyed by ID rather than username), and 'from local database' hints at the data source. However, there is no explicit when-to-use/when-not or named alternative guidance, leaving the agent to infer routing from the 40+ sibling tools.

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