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

Annotations already declare non-read-only, non-destructive, open-world behavior; the description adds the required scope 'sshkeys.write', which is genuinely useful auth context an agent cannot get from the annotations. It does not mention idempotency or duplicate-key behavior, keeping it short of a 5.

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 tight sentences, zero waste, with the action and its purpose front-loaded before the scope constraint.

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?

Annotations cover the safety profile and the description supplies the scope requirement; with only two parameters and no output schema, little else is needed. The undocumented 'name' parameter is the one remaining gap.

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 50%: public_key is fully documented with a format example, while name is undocumented in both schema and description. The description adds no parameter-level detail, so the baseline 3 applies at this coverage level.

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?

Names a specific verb (saves) and resource (public key) plus the concrete benefit (passwordless access for new machines). It clearly reads differently from list_ssh_keys or delete_ssh_key, though it never explicitly contrasts with those siblings.

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 'so new machines can be reached without a password' clause implies the context of use, but there is no explicit when-not guidance and no mention of the alternative sibling tools (list_ssh_keys, delete_ssh_key).

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