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

readOnlyHint=true already establishes the safety profile, and the description adds real context beyond it: results are 'confirmed' (implying unverified events are excluded), ordered newest-first, capped at 200, and on-air couples are annotated with a {kind, status} object where status='split' means exes. It does not disclose whether the 200 cap truncates silently or whether pagination exists.

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 tight sentences: what the data is and its limits first, then filtering, then the embedded couple semantics. Every clause carries information and nothing is padded.

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 does the right work by explaining the one non-obvious return field (couple.kind/status) and the result cap. It leaves unstated what a bare event record contains (actor, target, timestamp) and whether the 200 limit implies truncation, which keeps it from a 5.

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 both parameters carry their own ID/slug examples plus a pointer to list_shows, so the baseline is 3. The description only adds the 'and/or' combinability nuance, nothing the schema doesn't already convey.

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+resource ('Confirmed follow/unfollow events among castmates') with scope (castmates only), ordering (newest first) and a hard cap (up to 200). It is distinguishable from list-style siblings by being an event stream, though it never explicitly contrasts itself with get_follow_graph or get_follower_history.

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 explains how to narrow results ('Filter by season and/or contestant') and implies both filters are optional, but gives no guidance on when to pick this tool over get_follow_graph or get_follower_history, nor when to go unfiltered.

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