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

Annotations declare destructiveHint=true and readOnlyHint=false, but the description goes well past them: it specifies what actually changes per mode (every slide's background, typefaces, text colors), what is preserved (sizes are kept), and the mechanism for interfaces (rewrites brand.css so var(--brand-*) consumers update). That is exactly the kind of mutation-scope detail the annotations cannot convey.

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?

Purpose is front-loaded in the opening clause, then each sentence maps to one mode and one actionable instruction. Dense but every clause carries information; no restating of the name or title.

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 carries return-value burden lightly and appropriately (it points to napkin_slide_view for verification instead). For a 5-parameter, zero-required-parameter tool with three behavioral modes, the only gap is what happens when no target is supplied or when multiple mode parameters are combined.

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 the baseline is 3. The description nonetheless adds meaning beyond the schema: it explains that omitting kitId yields the workspace brand, that deck takes a board id, and — most valuably — the semantic selection rule for `accent`. It does not clarify whether deck and interface are mutually exclusive, which keeps it from a 5.

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 (restyles a piece in the brand) and then disambiguates the three target types — deck, interface, accent — with concrete effects for each. An agent can tell exactly what the tool does and how it differs from siblings like napkin_deck_set_theme or napkin_interfaces_write.

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 gives the condition for using `accent` (piece is about one product/campaign with its own brand color, and tells you to read the kit's Colors section), states a when-not case (docs need nothing because they read the brand at export), and names a verification follow-up (napkin_slide_view). This is the rare case of explicit when/when-not/next-step guidance.

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