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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so safety is covered. The description adds genuine context beyond that: ordering of results, that every layout adapts to every size, fits its text, inherits brand colors/faces/logos, and that the logo fills itself in. It does not discuss pagination or whether workspace scoping changes the result set.

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-loads the verb, resource and composition target, then the ordering rule, then the field semantics, then the selection taxonomy. Dense and mostly waste-free, though the trailing layout enumeration is long and only a picker list keeps it from being bloat.

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?

There is no output schema, so the description carries the burden of describing the return contents — it does so by naming the (needs filled, takes optional) field distinction and the ordering. Combined with the selection taxonomy, an agent can call this and act on the result without further discovery.

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?

Only one parameter (workspace) at 100% schema coverage, so the schema already documents it and the description does not need to. The needs/takes explanation refers to returned layout metadata rather than to input parameters, so 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?

States a specific verb and resource ('Lists the slide layouts') and ties it directly to its consumer, napkin_deck_compose, which is a sibling tool. The added detail that brand-kit layouts come first, then built-in ones, makes the scope unambiguous versus other napkin_* list tools.

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 selection by slide intent: 'Pick by what the slide has to say: one line (statement), a number (stat), a quote, a list (points, steps), an event...'. It also names the downstream tool it feeds, so an agent knows this is the discovery step before composing. No inference required.

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