get_follower_history

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior: one series per account including the caller's own, oldest-point-first ordering, one point per snapshot day, and that gaps mean nobody refreshed — all of which prevents misreading the data.

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 short sentences, front-loaded with the core purpose, then output composition, then the data-granularity caveat. Nothing is redundant with the title or schema, and every sentence carries information an agent needs.

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 bears responsibility for explaining return values, and it does so well: metrics, per-account series, ordering, and gap semantics. The only gap is the concrete container/shape of the response (e.g., whether series are keyed by account id), which would make it fully self-sufficient.

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% and the single 'period' parameter is fully documented with its enum and default, so the schema carries the load. The description only refers to 'the window' without adding format or interpretation detail beyond that, which is the expected baseline when the schema is complete.

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 names a specific resource (follower history) and immediately specifies the metrics returned — follower count and engagement rate — plus the per-account series structure. It is clearly distinguishable from sibling analytics tools like get_overview or get_account_insights, though it never explicitly compares itself to them.

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 describing a time-windowed trend series, which tells an agent this is for historical/trend questions rather than a current-state lookup. However, there is no explicit when-to-use versus when-not, and no mention of the sibling insight tools an agent might otherwise pick.

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