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

Annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, so the safety profile is covered. The description adds one non-obvious trait — the removal succeeds even when the target is invisible — but says nothing about permissions required, reversibility, or what happens to the subscription record.

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 with the action front-loaded and the scope nuance trailing; no filler and everything earns its place.

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 simple 3-parameter mutating tool with no output schema and full annotation/schema coverage, the description is nearly sufficient. Only a brief note on the effect of the removal (or required authority) would make it 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 description coverage is 100%, including the id/type pairing rule and the op_key idempotency contract, so the schema carries the semantics. The description adds no parameter-level information, making the baseline 3 appropriate.

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 ('Remove one of your subscriptions') and adds a distinctive scope qualifier ('even if its target is no longer visible to you') that separates it from the sibling 'follow' and from a generic unsubscribe. It stops short of naming the alternative explicitly, but the operation is unambiguous.

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?

The phrase 'even if its target is no longer visible to you' implies a usage condition for cleanup of stale subscriptions, but no explicit when-to-use vs when-not guidance or named alternatives (follow, block, mute, manage_membership) are offered. Usage is implied rather than stated.

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