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

Adds real context beyond the annotations: an ownership/auth precondition, the role-granting boundary, the return payload (URL, QR URL, share_text), and the non-obvious fact that it does NOT message anyone. This clarifies the side-effect surface that the readOnly/destructive hints alone don't convey.

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?

The precondition 'Owner only' is front-loaded, and each of the following sentences carries distinct, non-redundant information (constraint, return values, side-effect clarification, revocation pointer). No 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 two-parameter, no-output-schema tool, the description supplies the preconditions, the grant boundary, the return artifacts, and the follow-up path, so an agent has everything needed to call it and explain the result correctly.

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 both the days validity window and the editor/viewer role are already documented in the schema. The description reinforces the editor/viewer concept and the time limit but adds no syntax or constraints beyond what the schema provides, so the 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?

States a specific verb and resource ('Create a time-limited link for a teammate to join this workspace') plus the exact access mechanism (WeChat sign-in). The link-based mechanism implicitly distinguishes it from a direct add_member, so an agent can tell what it produces without opening the schema.

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 the precondition ('Owner only') and a clear exclusion ('Cannot grant owner'), and points to where existing invites are revoked (Members). It stops short of explicitly contrasting with the sibling add_member, leaving the choice between link-invite and direct-add to inference.

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