npm_owner_add

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

Annotations already mark destructiveHint=true and readOnlyHint=false, so the mutation nature is known. The description adds useful behavioral context: the tool grants publish and write permissions and resolves the user's email via /-/user/, saving the agent from supplying it. It does not contradict annotations, and it discloses the key side effect of granting permissions.

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 three sentences, each adding distinct value: the action, the permission effect, and the email resolution plus verification hint. It is front-loaded with the primary purpose and contains no filler or redundancy.

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 2-parameter mutation tool, the description is quite complete. It covers the action, effects, parameter handling, and a verification step. No output schema exists, so return value details are not required. It could mention idempotency or side effects further, but annotations cover destructive and idempotent hints.

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?

Input schema covers 100% of parameters with clear descriptions. The tool description adds extra meaning by explaining that the username is sufficient and no email needs to be supplied because it is resolved internally. This goes beyond the schema's per-parameter descriptions and helps the agent understand the data flow.

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 clearly states the action: 'Add a user as a maintainer of a package.' It also specifies the resulting permissions ('publish and write permissions'), which uniquely identifies this tool versus siblings like npm_owner_remove or npm_collaborators. The verb and resource are specific and 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 description provides an explicit alternative: 'Use npm_collaborators to verify before adding.' This tells the agent when to check first. However, it does not explicitly state when NOT to use this tool (e.g., for removing owners), though that is implied by the context and sibling names.

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