List spaces

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds the "active" scoping (only active spaces are returned) and enumerates the fields returned per space type, which is genuinely useful since there is no output schema. It does not cover pagination or ordering.

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 tight sentences, front-loaded with the core action and scope, followed by the returned fields and the one actionable downstream hint. No filler or redundancy.

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 single-parameter read-only list tool with full schema coverage and no output schema, the description compensates well by enumerating what each returned space type contains (saved/target/% for savings, balance for spending). Only minor omissions remain, such as pagination or result ordering.

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 100%, and the accountUid schema already documents the default-resolution behavior (STARLING_DEFAULT_ACCOUNT_UID / primary account). The description only alludes to "on an account" and adds no syntax or format meaning beyond the schema, so the baseline 3 applies.

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 ("Lists all active spaces on an account") and breaks the resource into its two subtypes, savings spaces and spending spaces, so an agent understands the scope without opening the schema. It partially disambiguates from siblings by equating savings spaces with savings goals, but never explicitly contrasts itself with list_savings_goals or get_spending_space.

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?

There is no explicit when-to-use/when-not or named alternative. The closing note that "a space UID can be used as categoryUid for transactions and payments" implies a downstream purpose for calling the tool, which is useful context, but it is not selection guidance against the many sibling list_* tools.

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