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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuinely non-obvious context beyond that: the removal is mutual ("on both sides") and group memberships survive intact, which materially affects what the agent should warn the user about.

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?

Two short sentences, zero filler, with the primary action and its side effect front-loaded and the scope caveat last. Nothing could be cut without losing information.

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 an output schema covering returns and annotations covering the safety profile, the description only needs to add scope and effect semantics — which it does. It would be marginally stronger if it noted irreversibility or what happens to an incoming pending request, but nothing essential is missing.

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%; the handle and idempotency_key params are fully documented in the schema, including the advice to resolve names via list_contacts. The description adds no parameter-level detail, so the baseline of 3 is 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 and resource ("Removes a contact") and adds two meaningful qualifiers: it also cancels a request you sent, and it applies on both sides. That is far more precise than a bare restatement of the title, though it does not explicitly differentiate itself from close siblings like block_contact or leave_group.

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 rather than stated: the parenthetical "or cancels a request you sent" reveals a second valid scenario, and "Shared groups are not affected" bounds the scope. However, there is no explicit when-to-use, when-not, or pointer to alternatives such as block_contact for a harder cutoff.

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