get_follower_active_hours

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered; the description adds real behavioral context on top: the 100+ follower prerequisite and Instagram's 30-day retention window. It stops short of describing failure modes or what happens when days_with_data is zero, which is the only remaining gap.

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?

Purpose is front-loaded in the first line, then Args/Returns/Limits in a scannable layout with no filler. The Returns section partially duplicates the existing output schema and the Args repeat schema defaults, which costs a point but harms nothing.

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 two-parameter read tool, the description covers purpose, trigger condition, parameter bounds, prerequisites, and data retention — everything needed before calling. Return shape is already carried by the output schema, so the brief inline summary is a bonus rather than a necessity.

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 0%, so the description carries the full burden and does: days is bounded 1-30 with default 30 and the reason for the cap, timezone gets an IANA format plus two concrete examples and a default. Both parameters are fully interpretable from the prose alone.

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 opening line states a specific verb and resource: it averages online follower counts per hour of the day. That is clearly distinguishable from siblings like get_audience_demographics or get_account_insights 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?

"Use when the user asks when their followers are most active or the best time to post" gives an explicit triggering condition, and the timezone sentence adds an operational instruction. It does not name an alternative or a when-not-to-use case, which keeps it 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.