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

With no annotations, the description carries the full burden, and it discloses meaningful behaviors: cache-only read, server-side execution, 1–20 scope limit, and rejection of custom attribution windows. It does not describe output/pagination or error behavior, which is a minor gap for a read tool.

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 text is front-loaded with purpose, uses labeled REQUIRED/DATE PARAMS/EXAMPLE sections, and includes one useful example without redundant prose. Every sentence adds operational value.

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 10-parameter tool with no output schema and no annotations, it supplies enough to make a correct basic call, including validation constraints and date formats. It does not describe the response shape or explain optional sort/pagination/consistency parameters, so it is strong but not fully complete.

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?

With 0% schema description coverage, the description compensates for the most critical parameters: group_by, scopes, date_from/date_to, and attribution, plus a full JSON example. However, it omits the valid group_by value 'ad_group' and instructs callers to use product_id even though the schema has no product_id property, weakening its reliability.

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 opens with a specific verb and resource: 'Server-side batch overview for comparing multiple explicit scopes' and adds concrete constraints like 1–20 scopes and cache-only read from tiktok_insights_daily. This clearly distinguishes it from single-scope or row-level insights tools even though it does not name a sibling explicitly.

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?

It gives clear usage context: use it for multi-scope comparisons without client-side fan-out, and it provides hard rules for date fields and attribution. It does not explicitly mention alternatives or say when not to use it, 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.