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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, covering the safety profile. The description adds the specific fields returned, which is useful context, but does not disclose additional behaviors like error handling, rate limits, or response size. Given the annotations, a 3 is appropriate—the description contributes some value but not rich behavioral details.

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 a single, well-structured sentence that front-loads the resource and action, then enumerates the returned fields without waste. It is appropriately concise for a simple read tool.

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 tool with two parameters, no output schema, and read-only annotations, the description is nearly complete. It states what it returns and covers both video and photo posts. Minor gaps like error handling are not critical given the simple nature. The expand parameter is explained in the schema, so the description need not repeat it.

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 coverage is 100%—both id and expand are fully described in the schema. The description does not add meaning beyond the schema, though it lists output fields which indirectly help understand the expand parameter's purpose. Baseline 3 applies when the schema handles parameter documentation.

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 tool retrieves a single video or photo post by ID and lists the exact data fields returned (caption, plays, likes, etc.). This distinguishes it from sibling tools like tiktok_video_comments or tiktok_video_transcript, which serve different purposes.

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 usage for retrieving post stats but does not explicitly contrast it with alternatives. There is no 'use this for X, use that for Y' guidance. The expand parameter in the schema offers some context for when to request the full response, but the description itself lacks explicit when-to-use vs. when-not-to-use advice.

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