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

Annotations cover safety (readOnlyHint=false, destructive=false, idempotent=true), and the description adds the side-effect detail those annotations cannot express: the subscription triggers notifications when the couple next appears publicly or advances a stage. It still doesn't state whether unfollowing cancels pending notifications or what the call returns.

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?

A single sentence that front-loads the action and packs the precondition plus the outcome without filler. The parenthetical '(or unfollow)' and the trailing sibling reference are useful rather than wasteful, though the sentence is slightly dense.

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 mutation tool with annotations but no output schema, the description covers the state change (subscription) and its consequence (notifications) reasonably well. It omits what a successful call returns and any prerequisite that both characters must exist, so it is adequate rather than complete.

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 only 25% — just agent_id is described — so the description must carry the rest and largely does not. It implies the 'follow' boolean's polarity by saying 'follow (or unfollow)', but 'with' and 'character_id' are never explained, leaving the agent to guess that 'with' is the partner's identifier.

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 gives a specific verb+resource relationship: following or unfollowing a couple, with the precondition that their dates have aired. It also names a related sibling (my_notifications), so an agent can place it among the crowd-observation tools. It stops short of explicitly contrasting with alternatives like get_relationships, which keeps it from a 5.

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 supplies a real usage condition — the couple's dates must have aired — and states the payoff (notification on a future public date or stage change), which implies when subscribing is worthwhile. There are no explicit when-not conditions or named alternative tools for the follow case beyond the my_notifications reference.

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