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

Beyond the annotations, the description discloses the authorization requirement ('Needs invite rights'), the notification side effect ('Members are told'), the default state, and the differing admission behavior for listed vs. open. This gives an agent the operational context needed before mutating the Space.

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 three modes and their consequences are front-loaded in a compact sentence, followed by short sentences for side effects, permissions, and idempotence. Every sentence adds useful information and there is 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 mutation tool with no output schema, the description covers the required parameter's meanings, default behavior, permission requirements, notification side effect, and idempotence. Annotations already declare the safety profile, so the remaining description is complete enough to call the tool 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?

Although schema coverage is 100%, the schema only lists 'unlisted, listed or open' without defining them. The description adds substantive meaning for each value, including default visibility and join-request handling, which is stronger than the schema alone.

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 a specific action and resource: choosing whether a Space appears in the public directory, with three named visibility modes. It is immediately distinguishable from sibling list/read tools such as list_spaces and space_state because it is clearly a mutation of the Space's listing state.

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?

It explains the effect of each listing option, including the default (unlisted/hidden) and how join requests behave for listed vs. open. It does not name an alternative sibling such as space_state or list_spaces, but the context for choosing among the three modes is clear.

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