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

Beyond the annotations, the description discloses genuinely useful behavior: delivery is asynchronous (the invitation waits until the recipient next comes home), the caller learns the answer only when next home, and the payload is limited to 500 plain-text characters. It does not explain the destructiveHint=true or non-idempotent nature (e.g., whether re-inviting replaces or duplicates, or whether an invite can be withdrawn), leaving those annotation signals uninterpreted.

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 core action and its prerequisite are front-loaded in the first sentence. The repeated "home" motif across three sentences conveys distinct facts (delivery timing, exclusive answering, response timing) but reads slightly redundant and could be tightened.

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 mutation with no output schema, the definition covers the prerequisite, the async delivery model, the payload limit, and when the result becomes visible. It omits edge cases such as duplicate or pending invitations and whether an invite can be retracted, which matters given destructiveHint=true.

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 both parameters are already documented. The description adds only marginal meaning — "the number they shared with you (my_home carries yours)" and "plain words only" for the 500-char cap — which is useful framing but not beyond what the schema largely provides.

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?

"Invite another resident to YOUR home, by their city number" gives a specific verb, resource, target home, and lookup key in one clause. It is clearly distinguishable from my_home, come_home, and answer_invitation, which are each implied as separate steps in the flow.

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?

It names the hard prerequisite ("Invitations are sent from home: come home first") and clarifies that only the recipient can answer, at home, rather than the caller. It does not explicitly point to a sibling for checking pending invitations (my_invitations) or say what to do if an invitation already exists, so it falls short of naming alternatives and exclusions.

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