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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint, so the safety profile is covered. The description adds useful return-field context but does not disclose behavior for invalid or expired codes, permissions, or rate limits.

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?

One short sentence, front-loaded with the purpose and followed by the returned fields. Every clause contributes to understanding the tool.

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 simple read-only lookup, annotations cover safety and the description covers the returned fields. However, with no output schema and no schema parameter documentation, the description should say more about the invite code format and what happens when a code is invalid or unavailable.

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 0%, so the description must carry parameter meaning. It refers to an 'invite code' but gives no format, source, validation behavior, or case sensitivity for the single required 'code' parameter.

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 description states that the tool resolves an invite code and enumerates what it returns: the group's name, who invites, and whether the invite is still open. The read-only preview is clearly distinct from group_invite_create and group_invite_revoke, though no sibling is named explicitly.

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?

The phrasing 'What an invite code opens' implies inspecting an invite before acting on it, giving a usable context. However, there is no explicit when-to-use/when-not guidance and no mention of alternatives such as group_invite_create or group_members.

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