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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so the safety profile is covered. The description adds value beyond that by describing the returned shape (name, origin idea, node count) and clarifying what a 'field' actually is, which the annotations cannot convey.

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 with zero filler. The scope (which workspace) and resource definition come first, and the pointer to the sibling is appended where it is most useful.

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?

There is no output schema, so the description carries the burden of indicating the return shape, and it does so explicitly. Combined with the fully documented workspace parameter and the sibling pointer, an agent has everything needed to call this correctly.

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?

There is a single parameter with 100% schema description coverage, so the schema already documents the workspace slug and its default/override behavior. The phrase 'in the active workspace' loosely implies workspace scoping but adds no syntax or edge-case detail beyond the schema. 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?

Uses a specific verb ('Lists') and resource ('Prism fields'), and disambiguates the resource by glossing it as 'idea-exploration canvases'. It also enumerates what the listing contains (name, origin idea, node count), so an agent can tell it apart from prism_fields_get without opening either 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?

Explicitly routes the agent to the sibling for detail work: 'Fetch one with prism_fields_get for its nodes', establishing the list-vs-get alternative. It gives clear context but no explicit when-not condition or prerequisites, so it stops just short of a 5.

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