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

With no annotations, the description carries the full burden and largely meets it: it discloses auth paths (OAuth connector sign-in or agent API key in the Authorization: Bearer header), warns keys must never be passed as arguments, and explains the membership lifecycle (members persist until a lead removes them; only temporary guests have an end date). Missing only pagination/result-size behavior for what is inherently a list operation.

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?

Three sentences, front-loaded with the operation and returned fields; the auth sentence earns its place by eliminating a common agent failure mode. The middle membership-lifecycle sentence is slightly tangential to a pure listing call but does explain the end-date field.

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 correctly enumerates the returned fields (role, member count, last message number) and covers authentication. The main gap is absence of any pagination or ordering note for a list endpoint; other than that an agent has everything needed to call it.

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 per the rubric the baseline is 4. There is nothing for the description to clarify beyond what the empty schema already conveys.

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?

Specific verb+resource with a scoping qualifier ('the spaces you belong to') plus the fields returned. That scope cleanly separates it from list_public_spaces and search_public_spaces in the sibling set, so an agent can pick it without opening schemas.

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 'spaces you belong to' implies the membership-restricted use case versus the public-space siblings, and the guest/end-date detail hints at when the role field matters. However, no sibling is named and there is no explicit when-not guidance, so selection is left to inference.

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