figma_add_mode

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

With no annotations, the description carries the full load: it discloses the Desktop Bridge prerequisite and implies a mutation. It does not say whether existing variables receive default values in the new mode, whether duplicate mode names are rejected, or what happens on failure — notable gaps for a state-changing tool.

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 short sentences, front-loaded with the action, followed by the minimum conceptual context and the hard prerequisite. Nothing is redundant.

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 two-parameter mutation with no output schema and no annotations, the description covers purpose and prerequisite but leaves the post-condition of the new mode (default values for existing variables) and return/error behavior unstated.

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% and both parameters already include examples and a pointer to figma_get_variables for the collectionId. The description adds no parameter-level meaning beyond the schema, so the baseline 3 applies.

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 first sentence states a specific verb and resource: adding a mode to an existing variable collection. It is clearly distinguishable from figma_rename_mode and figma_create_variable_collection, though it never names those siblings explicitly.

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?

It supplies a real precondition (Desktop Bridge plugin must be running) and explains conceptually what modes are for, but gives no guidance on when to add a mode versus rename one, or how this relates to figma_rename_mode / figma_create_variable_collection.

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