Add component property

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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=false, idempotentHint=true), so the description's added value is what matters, and it delivers a lot: what binding actually does ('instances then edit the label without detaching'), the reuse contract with the `reused: true` flag, the return value shape, and environment limits (Design verified; FigJam and Slides unverified).

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?

Front-loaded with the core action, and every clause carries information (four type behaviors, the return key, the reuse rule, sibling routing, editor coverage). It is dense and packed into one long paragraph, which slightly hurts scanability, but there is little dead weight.

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?

With no output schema, the description correctly fills the gap by stating what is returned (the property `key` as name + #id that figma_set_instance_properties accepts) and that a plain name works too. Combined with type semantics, reuse behavior and editor support, an agent has everything needed to call it 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?

Schema coverage is 88%, so the baseline is 3. The description still adds genuine meaning on top: it explains that bindNodeIds wires text layers for TEXT, that BOOLEAN drives show/hide, that INSTANCE_SWAP's default is a component id, and that VARIANT only applies to sets — semantics the bare enum does not convey.

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+resource ('give a component ... a property that instances can change') and immediately enumerates the four property kinds with their distinct semantics. It clearly differentiates itself from figma_edit_component_property, figma_delete_component_property and figma_create_slot by naming when each is the right call.

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: use figma_edit_component_property to rename, re-default or unwire, and figma_create_slot for slots. It also documents the re-call/reuse case ('called again with a name and type that exist, it reuses that property') and notes VARIANT is 'on a set only', so both when-to-use and when-not-to-use are covered.

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