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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds traits annotations cannot express: per-row billing, that limit caps cost as well as rows, newest-first ordering, and an untrusted-input warning for user-generated content. That is genuinely valuable behavioral context beyond the structured fields.

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 tight sentences; purpose and match semantics are front-loaded, then routing, then return/billing, then the safety note. Every sentence carries distinct information with no filler.

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?

With no output schema, the description enumerates the returned fields (pk, text, commented_at, like_count) and the row cap, and covers both required parameters, billing, ordering, and trust handling. An agent has everything needed to call and interpret the result.

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%, so baseline is 3, but the description adds meaning the schema lacks: query is a case-insensitive substring match (schema only says 'Search text in comments'), and limit bounds cost, not just rows. It does not clarify the max of 1-100 beyond the schema.

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 (search), resource (TikTok comments), scope (across all users), match semantics (case-insensitive substring), and ordering (newest first). It explicitly contrasts with the two closest siblings, so an agent can distinguish it without opening any schema.

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?

Gives an explicit when-to-use ('brand or keyword mentions') and names both alternatives with their selecting conditions ('get_tt_comments_by_user for one author', 'get_tt_comment_by_id for a comment's full record'). Nothing is left to inference.

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