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

Annotations already cover the safety profile (readOnly, non-destructive, closed-world), and the description adds real value on top: the return contents (what, when, with whom, status, style, where to book the same host) and the lifecycle edge case that sharing revocation yields a 404. That revocation behavior is not derivable from the schema or annotations.

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?

A single front-loaded sentence that enumerates return fields without filler. The nested parenthetical and dense field list make it slightly harder to scan, but nothing is superfluous.

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 read tool with no output schema, the description does the heavy lifting by summarizing the returned invitation fields and the 404 condition. Only the sibling relationship to get_booking and share_booking_as_invitee is left unstated.

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 coverage is 100% and the schema's own token description already explains that it is the invitation address or bare token, so the description's restatement adds no new meaning. Baseline 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?

The verb 'Returns' plus the specific resource 'the invitation behind a shared booking's link' makes the purpose unambiguous, and the '.../i/<token>' form implicitly separates it from id-based lookups like get_booking. It stops short of naming that sibling, so differentiation is inferred rather than stated.

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?

Usage is implied by the token form (use this when you have a share link, not a booking id), and the 404-on-stopped-sharing note hints at a failure condition. There is no explicit when-not or alternative routing, e.g. no pointer to get_booking or get_public_profile.

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