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

Annotations already say this is a non-read-only, non-destructive, closed-world write, so the description's real value is the two extra facts: the create is atomic, and billing falls on the owner while invited members need no subscription. Those are non-obvious side effects an agent cannot get from structured fields.

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 short sentences with the action and its main consequence front-loaded; no filler or restatement of the tool name.

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 not be explained, and the billing/atomicity behavior is covered. Still missing for a write tool: the required idempotency key's retry semantics and any note on what identifying fields are needed to form the space.

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 0% and the description names none of the three parameters. It says nothing about title/purpose constraints or, more importantly, what the required idempotency_key means or how retries interact with it, so the description does not compensate for the coverage gap.

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 and resource ('Create a private Space') plus the side effect of owner membership being established in the same operation. The 'private' qualifier implicitly separates it from the public_space_* siblings, though it never names them.

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?

No indication of when to use this versus alternatives such as private_space_personal or private_space_list, and no prerequisites (e.g. whether the caller needs an existing account/actor) are given. The agent must infer context entirely.

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