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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: the ownership/join membership rule and the share-link exclusion, which tells the agent results may be incomplete in a predictable way.

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?

A single dense sentence with the core purpose front-loaded and the caveat trailing. The inline response-shape enumeration is slightly heavy in prose form, but it earns its place given there is no output schema.

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 compensates by describing the returned object fields (id, title, url, role, rev, updated_at, default) and what `default` means. That covers what an agent needs to consume the result; only the ordering/pagination behavior is unaddressed.

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 the baseline is 4 and there is nothing for the description to disambiguate. The inline enumeration of return fields is a bonus rather than a parameter concern.

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: 'List the design systems (type design-system) you own or have joined', with a clear scope qualifier. It doesn't explicitly contrast with nearby siblings like system_default or system_install, but an agent can still tell what it returns 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?

The exclusion clause ('Systems reachable only through a share link are not listed') gives useful scoping context, implying when results will be incomplete. However, there is no explicit when-to-use guidance or routing to alternatives such as system_default for retrieving just the default system.

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