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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description adds domain context (pieces are composable into a part, or shared across a style), but says nothing about behavior on an unknown ID, error modes, or what the returned piece contains.

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 short sentences, front-loaded with the action and resource. The second sentence is domain framing rather than filler, though it leans closer to background than to operational guidance.

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 simple single-parameter read with annotations covering safety and no output schema, the core is present. However, an agent is left guessing about the ID's provenance and result shape, which matters because there is no output schema to fall back on.

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 0% for the single parameter, so the description is the only source of meaning. It says only 'by ID' — establishing that the parameter is an identifier but not where to obtain it, whether it is the numeric ID from list_pieces, or any format expectations.

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 ('Get a reusable SVG building-block piece by ID') and adds what a piece conceptually is. It implicitly separates itself from list_pieces (single fetch by ID) but never names that sibling, so it falls short of full differentiation.

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 'by ID' framing implies you must already have an identifier, which hints at using list_pieces first, but the description never says that or states any when-to-use / when-not-to-use condition. Usage is inferred rather than instructed.

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