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

Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds real behavioral context beyond that: the change takes effect immediately ('goes live at once'), the candidate set is restricted, and sign-in is required. It does not say what happens to the previously live version, but the addition is substantive.

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 short sentences, no filler. The core action is front-loaded, followed by the eligibility constraint and the auth prerequisite in descending order of importance.

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 full schema coverage, an output schema and a complete annotation set, the description only needs to supply the human-judgment details — eligibility, immediacy, auth — and it does all three. Nothing an agent needs to invoke this correctly is missing.

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 coverage is 100%, so both parameters are already documented (space slug, version number). The description adds eligibility semantics the schema cannot express — only versions flagged rollback: true in the versions listing are valid inputs — which meaningfully narrows how 'version' should be interpreted.

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 precise verb+resource: 'Make an earlier version of a hosted space live again.' The eligibility clause '(rollback: true in versions)' implicitly separates it from publish (which pushes a brand-new version) and versions (which lists them), so an agent can route 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?

Gives a hard precondition for use — only a version that was previously live ('rollback: true') may be selected — plus the auth requirement ('Needs sign-in'). It never names an explicit alternative tool for the other case, so it stops just short of full when/when-not guidance.

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