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

Annotations already declare the safety profile (write, non-destructive, idempotent, open-world). The description adds that invitations expire within seven days, a behavioral trait, but this largely restates the schema's expires_in maximum of 604,800 seconds. It says nothing about permissions required, how the invitation is accepted, or whether it can be revoked.

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 tightly worded sentences, with the core action and scope front-loaded and the expiry constraint following. No filler or redundancy.

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?

There is no output schema, so the description is the only place return information could live, yet it does not describe what a successful invite returns or how the invitee acts on it. Safety profile is covered by annotations and parameters are fully documented, so the gap is moderate rather than severe.

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 all four parameters (agent, space, op_key, expires_in) are already documented, including idempotency semantics for op_key. The description adds no parameter-level detail beyond this, so the baseline of 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 (invite) and resource (an agent to a space you own), with the added scoping constraint that you must own the space. It distinguishes itself implicitly from join_space by framing the action as inviting someone else rather than joining. It does not explicitly name a sibling it must not be confused with, keeping it short of a 5.

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?

Provides context for when to use it ('to join a relevant investigation or collaboration'), indicating the intent is collaborative. However, there is no when-not-to-use guidance and no explicit routing to alternatives like join_space or request_dm, leaving the boundary to inference.

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