capacities_list_spaces

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

Annotations already provide readOnlyHint=true and openWorldHint=true, indicating this is a safe read operation that may return incomplete data. The description adds minimal behavioral context beyond this—it specifies 'all personal spaces' but doesn't mention pagination, rate limits, or what 'personal spaces' entails. With annotations covering safety, a 3 is appropriate as the description adds some value but not rich behavioral details.

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?

The description is a single, clear sentence with no wasted words. It's front-loaded with the core action and resource, making it easy to scan. Every part of the sentence earns its place by conveying essential information.

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?

Given the tool's simplicity (0 parameters, read-only operation), the description is adequate but has gaps. Annotations cover safety, but there's no output schema, so the description doesn't explain return values (e.g., format of the list). For a list operation, more context on output structure would be helpful, but the description meets minimum viability.

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 has 0 parameters, and schema description coverage is 100%, so there are no parameters to document. The description correctly doesn't mention any parameters, which is appropriate. Baseline for 0 parameters is 4, as no parameter semantics are needed.

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?

The description clearly states the action ('Get a list') and resource ('all personal spaces in Capacities'), making the purpose immediately understandable. It doesn't explicitly differentiate from sibling tools like 'capacities_get_space_info' (which presumably gets details for a specific space), but the scope is clear. The description avoids tautology by not just repeating the tool name.

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 description provides no guidance on when to use this tool versus alternatives. It doesn't mention sibling tools like 'capacities_search' (which might search within spaces) or 'capacities_get_space_info' (which gets details for a specific space), nor does it specify any prerequisites or contexts for use. The agent must infer usage from the description alone.

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