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

Annotations already mark it as a non-readonly, non-idempotent, non-destructive write, but the description adds value beyond them: the link is returned only once (so it must be captured immediately), invites are limited per account, and the operation requires owner credentials. That is exactly the kind of consequence an agent needs before calling a non-idempotent write.

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?

Four short sentences, front-loaded with the action, then constraint, then side effect, then the one-time return caveat. Nothing is padded and each clause carries operational 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?

For a single-optional-parameter tool with no output schema, the description covers action, prerequisites, limits, and the one-shot nature of the returned link. It stops short of describing the return shape (e.g., a URL string vs. an object), which is the one gap given there is no output schema to lean on.

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?

Only one optional parameter (note) exists and the schema documents it at 100% coverage, including an example. The description adds no parameter-level detail, so the schema baseline of 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?

States a concrete verb+resource ("Make one invite link") and pins the cardinality ("one"), which separates it from the sibling list_invites and from redeem_code. An agent can identify the operation and its actor ("key owner") without opening the schema.

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?

Gives the precondition ("as the key owner", "Needs a key") and a scarcity context ("a few per account") that tells the agent to be economical. It does not explicitly name when-not-to-use or point to the counterpart tool (redeem_code), so it falls short of full routing guidance.

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