List spaces

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds valuable context beyond annotations: results are limited to spaces the authenticated user belongs to, results are unordered, pagination uses nextPageToken, and space_type filters server-side. This is strong complementary behavioral detail.

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 dense but efficient sentences. The core purpose and returned fields are front-loaded, followed by usage guidance and pagination details. Every sentence earns its place with no filler or repetition of schema content.

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?

For a read-only list tool with rich annotations and a fully documented schema, the description covers required output fields, pagination, ordering, server-side filtering, and the tool's role in the broader workflow. Nothing essential for an agent to select and invoke it 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?

Input schema covers all three parameters at 100%, so the baseline is 3. The description adds meaningful extra semantics by explaining that space_type narrows results server-side and that page_token comes from nextPageToken, which helps an agent use the parameters correctly beyond the schema text.

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 ('Lists'), resource ('spaces the authenticated user is a member of'), and the key returned fields. Clearly differentiates itself from search_spaces by noting this is the discovery entry point and that no text search is available here.

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?

Explicitly positions the tool as the discovery entry point whose results feed other tools. Provides concrete routing guidance: use space_type for server-side narrowing, match displayName client-side, and use search_spaces for admin-only text search. Also explains pagination behavior.

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