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

Annotations already declare readOnlyHint/non-destructive, and the description adds substantive behavior: daily snapshots captured every ~23h, platform-native un-normalized stats, and the special google_business per-location series with no follower count. That is real context an agent cannot get from the annotations or schema.

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 dense sentences, purpose front-loaded, then conditional requirements and return-shape caveats. Every sentence carries information, though the placement_id rule restates the schema nearly verbatim.

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 usefully sketches the return (daily snapshots, records[].stats being platform-native, the google_business metric list). It omits pagination, result limits, and retention window, which an agent might need for large date ranges.

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 all four parameters, and the placement_id conditional is duplicated there. The description adds no syntax or format detail for from/to beyond the ISO 8601 note already present in the schema, so baseline 3 applies.

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 and resource ('Get the follower/engagement timeseries for a profile'), which implicitly separates it from post_stats and summary_get. It stops short of naming those siblings explicitly, so an agent must infer the boundary rather than being told.

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 conditional usage guidance for placement_id: required for facebook, linkedin, telegram and google_business, omitted for the rest, and points to profiles_placements as the source. It offers no guidance on when to choose this tool over post_stats or summary_get.

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