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

Annotations already declare destructive, non-idempotent, and open-world behavior, so the safety bar is lower. The description adds genuinely useful context beyond them: the invite is single-use, defaults to a 24-hour expiry, and the memory vault stays private. It does not explain what revocation or failure looks like, but it goes well beyond the 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?

Front-loaded with the core action, followed by short, scannable sentences covering scope, single-use/expiry, and the privacy note. Every sentence carries some weight, though 'Your memory vault stays private' is somewhat tangential to the invite mechanics.

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 3-parameter tool with full schema coverage and annotations covering the safety profile, the description supplies the key behavioral facts an agent needs: scope, single-use nature, and default expiry. It is essentially complete, with only the omission of expected failure/rejection behavior as a minor gap.

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 room_id, connection, and expires_in_seconds are already fully documented, including the default of 86400 and the 60-86400 range. The description only reiterates the expiry control ('Use expires_in_seconds for a shorter expiry') without adding new syntax or meaning, matching the baseline of 3.

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 specific verb+resource: invite a new agent to a shared room, with the scope narrowed to 'the selected shared room in this workspace'. It also clarifies the membership boundary ('Other rooms require explicit membership'), helping distinguish from broader room tools, though it does not name a specific sibling like room_join or room_bootstrap.

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 some usage context ('Other rooms require explicit membership', 'Use expires_in_seconds for a shorter expiry'), implying when the tool applies and how to shorten expiry. However it never says when to prefer this over siblings such as room_join, contact_room_start, or request_create, so routing guidance is only implied.

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