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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description's value-add is the security disclosure "Holding the token grants no conversation or knowledge access" — a genuinely useful scoping statement not present in the annotations. It does not cover failure modes (invalid/expired/revoked token behavior), which keeps it below 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?

Two sentences: the first front-loads what is returned and when to call it, the second adds the security caveat. Nothing is redundant or padded.

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?

An output schema exists, so return values need no explanation, and the tool is simple with one required parameter. The description covers purpose, timing and the token's limited power, but leaves out token provenance and error behavior for invalid or expired invitations.

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?

Only one parameter and 0% schema description coverage, but the schema's regex `^iv_[0-9a-f]{64}$` already conveys the token format. The description refers to "the token" but never says where an agent obtains it (invitation link, space_list_invitations), so it does not fully compensate for the missing schema description.

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 uses a specific verb ("Show"/preview) against a specific resource (an invitation) and names the exact fields surfaced: Space title, purpose and inviter. That distinguishes it cleanly from space_accept_invitation, space_approve_invitation and space_list_invitations without requiring 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?

The phrase "before requesting or accepting membership" establishes the sequencing context that selects this tool over the accept/request siblings. It stops short of explicit exclusions (e.g., what to do if the token is expired, or when to use space_get_request instead), so it is clear context rather than full routing guidance.

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