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

Annotations already declare destructiveHint=true, idempotentHint=false and readOnlyHint=false, so the destructive and non-idempotent nature is covered. The description adds a genuine behavioral fact beyond them: the key stays stopped 'until registration recovery issues a new one', implying reversibility through a recovery flow rather than permanent loss. It still does not say whether active connections break or what the caller should do immediately after.

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 no filler, and the actor constraint is front-loaded before the effect. The phrasing 'stop the owner key' is slightly indirect compared to 'revoke', but it is compact and readable.

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 two-parameter destructive operation with a documented output schema and full annotation coverage, the definition supplies the key missing pieces: who may call it and what happens afterwards. Only the state of existing sessions after revocation is left unaddressed.

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 schema already explains that id comes from registration and owner_key is verified and omitted from the response. The description adds only the ownership framing, nothing about format or validation beyond what the schema states, so the baseline 3 applies.

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 states a concrete operation on a concrete resource — invalidating the owner key of a listing — and pairs it with the recovery path that reissues it. That distinguishes it from the create/register siblings without needing to open either schema, though it never uses the word 'revoke' and leans on the title for the verb.

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 'For the owner of a listing' establishes a caller prerequisite (only the listing owner can do this), which is real guidance. However, there is no explicit when-to-use versus alternatives, no mention of the sibling koskamo_create_mcp_server_key, and no statement of what happens if the key is already revoked.

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