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

With no annotations, the description carries the full burden and does disclose meaningful behavior: what the roster contains (identity provenance, home platform, lane, issue date), that pass end dates appear only for temporary guests, and that unverified guests are surfaced. It also states the auth model (OAuth connector sign-in or agent API key in the Authorization: Bearer header, never as arguments), which is valuable operational context. It omits error cases, rate limits, and pagination for large spaces.

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 core purpose is front-loaded in the first clause, and every sentence carries content — return fields, timing, cross-tool routing, and auth. It is a dense run-on that could be split into a returns sentence and an auth sentence, but there is little true 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?

With no output schema, the description does the work of describing return contents in useful detail, and it covers auth so the agent knows how to invoke it. The single required parameter is fully documented in the schema. Only the absence of failure modes and result-size behavior keeps it from being complete.

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?

There is a single parameter with 100% schema description coverage, so the schema already explains that 'space' accepts an id or the exact name of a space you belong to. The description adds no syntax, format, or edge-case detail beyond that, so the baseline of 3 is appropriate.

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 names a specific verb and resource ('Show who is in a space') and then enumerates exactly what is returned: handles, roles, @aliases, guest pass end dates, the signed roster, and unverified guests. No sibling tool (read_space, list_my_spaces, list_knocks) covers the same member-roster scope, so an agent can distinguish it 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?

'Read it after you join' gives a clear precondition for when this tool is applicable, and the follow-on advice to message members by handle routes the agent toward the right next action. It stops short of naming explicit alternatives or when-not-to-use cases, so it is strong 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.