create_component_instance

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

With no annotations, the description carries the burden of disclosing behavioral traits. It explains the two-component-type behavior (local vs library) and the corresponding parameter usage, which is valuable. However, it does not disclose potential errors, whether the operation is reversible, or what the return value is. For a mutation tool, this is moderate but not exhaustive.

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 three sentences, front-loaded with the primary action, and then concisely explains the two parameter usage cases. Every sentence adds necessary information with no repetition or fluff.

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 complexity (5 params, no output schema, no annotations), the description covers the main usage distinction well. It does not explicitly warn that one of componentId or componentKey is required despite neither being listed as required in the schema, which could lead to misuse. However, the description implies a component source is needed, and the schema covers positional details.

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 description coverage is 100%, so the baseline is 3. The description adds meaning beyond the schema by explicitly mapping componentId to the 'id field' and componentKey to the 'publishedKey field' from get_local_components, which is not present in the schema descriptions. This helps the agent select the correct parameter for the component type.

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 begins with a specific verb and resource: 'Create an instance of a component in Figma.' It clearly distinguishes from sibling creation tools like create_rectangle, create_frame, and create_text by focusing on component instances. It also adds a critical distinction between local and library components, which fully clarifies the tool's purpose.

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 gives clear guidance on when to use componentId vs componentKey based on whether the component is local or published. It references get_local_components, providing actionable context. However, it does not explicitly state 'use this instead of create_rectangle or create_frame,' relying on implicit differentiation from sibling names.

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