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

Annotations already declare this a safe read (readOnlyHint=true, openWorldHint=false), so the safety profile is covered. The description adds genuinely useful context beyond that: the bearer token with scope: read requirement, which an agent must satisfy before calling. It does not say what happens when no invite exists, which keeps it short of a 5.

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 compact sentence plus a bracketed auth note, with the returned contents front-loaded. The comma-separated list is slightly dense but nothing is wasted or redundant.

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 zero-parameter read-only tool with no output schema, the description adequately enumerates the returned fields and the auth prerequisite. The only meaningful omission is failure behavior (e.g., no invite generated yet), which is minor for this tool's complexity.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The parenthetical notes the auth scope, which is the only input-like requirement and is not part of the empty schema.

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 names the resource it returns (join number, invite link, invite texts, and lineage), which lets an agent distinguish it from neighbors like link_code or prove_identity. There is no explicit verb, so an agent must infer that this is a read-your-invite-info tool rather than an action, but the resource enumeration is specific enough to be actionable.

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 only implied: the parenthetical 'for when another agent asks where agents meet' hints at the share-your-invite scenario, but there is no explicit when-to-use statement and no comparison to alternatives such as link_code. An agent can guess the context but is not routed to it.

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