figma_add_slot_property

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

With no annotations, the description carries the burden and does substantial work: it discloses structural preconditions that will cause failure, and explains that fileKey changes the target without altering the active file or target lock, plus Cloud Mode rejection. It stops short of saying what happens if a slot property with that name already exists, or what the tool returns.

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 action and the alternative, then the constraints, then a clearly labeled mode-specific block. The multi-file paragraph is somewhat verbose and duplicates the fileKey schema text, but the structure makes skimming easy.

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 6-parameter mutation tool with no annotations and no output schema, the description supplies preconditions, optional-feature scope, and mode behavior. The remaining gap is error semantics (duplicate property name, invalid frame) and confirmation of what mutation is persisted.

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 every parameter is already documented in the schema, and the description's mention of 'description and preferredValues' plus the fileKey paragraph largely restates it. The only marginal addition is the SLOT-only scoping of the optional fields. Baseline 3 applies when the schema does the heavy lifting.

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?

Opens with a specific verb+resource ('Manually add a SLOT component property') and immediately scopes it as the manual alternative to figma_create_slot, a real sibling in the list. An agent can distinguish it from figma_add_component_property and figma_create_slot 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?

Names the alternative (figma_create_slot) and enumerates hard preconditions: the frame must be a direct child of the component, must not use GRID layout, and must not be nested inside another slot. It does not explicitly state the condition under which the other tool should be preferred, which keeps it 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.