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

Annotations already cover read-only and non-open-world safety, so the bar is lower. The description adds real behavioral context: the return shape (types, props, valid values), that a comma list scopes the response, and that responses become compact under parallel fill. It does not cover response size limits or pagination, but the added detail is substantive.

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 sentences, front-loaded with the return payload. No filler. Minor deduction because 'In parallel fill' is unexplained jargon that costs the reader without adding clarity.

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?

No output schema exists, so the description must carry return-value meaning, and it does sketch the payload shape (types, props, valid values). For a single-parameter read tool this is nearly complete; the only gap is deeper detail on the returned structure and the compact-mode format.

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 coverage is 100%, so baseline is 3. The description goes further by stating that a comma list narrows the result and that `components` becomes required in the parallel-fill case — a conditional constraint the schema text ('Omit for all') does not convey. That is meaningful added semantics.

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 the specific resource and what it returns: 'Full prop schemas for components (types, props, valid values)'. This distinguishes it from neighbors like get_style_reference or list_presets by naming the artifact returned. It does not explicitly name a sibling alternative, so it falls short of a 5.

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?

Adds one conditional usage hint ('In parallel fill, responses are compact and `components` is required'), which is genuinely useful context. However, it gives no guidance on when to reach for this tool versus get_style_reference, list_presets, or get_block, and the 'parallel fill' scenario is left unexplained.

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