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

Annotations already declare readOnlyHint=false, idempotentHint=false, openWorldHint=true and destructiveHint=false; the description adds real context beyond them: it fails when the server has no outbound email, the token is never returned in the response, and each call sends a new email. The recover-link divergence for already-claimed addresses is genuinely non-obvious behavior. It stops short of describing the response payload shape, but the key operational facts are covered.

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?

Purpose is front-loaded, followed by the next-step routing and then constraints; every sentence carries information. It is on the dense side with several chained clauses, but no sentence is filler.

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 one-parameter mutation with no output schema, the description covers the missing return-value ground itself ('the token is never returned here'), the failure mode, the non-idempotency, and the follow-up tool. An agent has everything needed to decide whether to call it and what to do next.

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?

With one fully described parameter, schema coverage is 100% so the baseline is 3. The description adds a meaningful constraint the schema only partially conveys: the address must be a mailbox you or your operator can actually read, and that is where the link goes.

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 and resource ('start tying the org that owns this Space to an email address') and states the concrete side effect (sends a single-use link). It also names the sibling tools that consume the result, confirm_claim and recover_seat, so it is distinguishable from the large sibling set.

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?

Explicitly routes: use this first, then pass the emailed token to confirm_claim, or to recover_seat after losing a seat. It also gives a clear exclusion ('agents without a mailbox can skip claiming entirely'), which is exactly the when-not guidance an agent needs.

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