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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds real behavioral context the annotations do not: this is a public demo limited to a single advertiser (page_id 116482854782233), and listings/statistics expose only approved public creatives for that advertiser.

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 sentences with no padding, but ordering is inverted: the demo caveat and sibling-tool behavior lead, and the tool's actual purpose is buried in the last sentence. The middle sentence about ad listings/statistics describes adjacent tools more than this one.

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-param, read-only check with no output schema, the description covers the demo scope, the advertiser restriction, and the verification intent, which is enough to call it correctly. Only the per-ID result shape is left to inference.

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 0% and the only param is an array of page IDs. The description reinforces that inputs are 'string Meta page ID's and that multiple IDs are checked individually, but adds no format, length, or batching limits beyond what the schema's pattern/maxItems already encode.

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 final sentence states a specific verb+resource+scope: 'Check whether each string Meta page ID is actively tracked by your account.' This distinguishes it from list_tracked_brands/search_tracked_brands (enumerate vs. verify a supplied set), though that contrast is only implied rather than named.

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?

Usage is implied by 'check whether ... is actively tracked by your account,' but there is no explicit when-to-use statement and no mention of the sibling tools (list_tracked_brands, search_tracked_brands) as alternatives for discovering brands. The demo constraint is a hard usage boundary but not phrased as guidance.

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