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

Annotations declare destructiveHint=true, openWorldHint=true, idempotentHint=false, readOnlyHint=false, which already signals this is a mutating, potentially destructive operation. The description adds some specific behavioral notes like 'its key can open new ones until removed' and 'Containers come back per restart policy', which are useful beyond annotations. However, it does not fully disclose side effects like session termination implications or permission requirements, so the added value is moderate.

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?

The description is a single, front-loaded sentence that efficiently lists the operations and key outcome. It is appropriately sized and contains no redundant information, though it could be slightly more structured with bullet points for clarity.

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?

Given the complexity (5 parameters, nested objects, destructive operations) and the lack of an output schema, the description is minimal. It states what the tool does and returns (the machine), but does not cover important context like return value details, error handling, or prerequisites. With annotations covering safety, it is borderline adequate but leaves gaps.

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%, so all parameters are documented in the schema itself. The description does not add syntax, format, or validation details beyond what the schema provides. Baseline 3 is appropriate when the schema does the heavy lifting.

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 clearly what the tool does: 'One machine action: add or remove the person's SSH public key ... end a session, schedule or cancel a restart.' This is a specific verb and resource (machine action) and enumerates the operations. It does not explicitly differentiate from siblings like RunProjectAction or RunServiceCommand, but the scope (machine-level actions) is clear enough that an agent can distinguish it.

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 description lists possible actions but does not explain when to use this tool versus alternatives. It gives some implied usage via the SSH key context (for SSH and SFTP to containers), but there is no explicit when-to-use guidance or exclusions. An agent must infer the context from the operations available.

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