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

Annotations declare readOnly=false, destructive=false, openWorld=false, so the description must add substance — and it does: it explains hidden slides are excluded, slide numbers and watermark aren't drawn, units are real pixels per layout, and the result is saved to workspace files vs returned as a download. That's meaningful behavioral detail beyond annotations.

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?

Five tight sentences, each earning its place: output format/resolution, single vs multi behavior, hidden-slide rule, where the file lives, and the PDF/PPT exclusion. Front-loaded with the primary purpose.

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?

Complete for a 3-parameter export tool with no output schema: it covers output type, size/dimensions, file count behavior, storage location, download URL semantics, and the alternative for other formats. Nothing critical is missing.

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 baseline is 3. The description adds meaning: slide numbers are '1-based, as the deck shows them' and omitted = every slide, and constrains the range for ad-unit use (post/story/leaderboard sizes). It also implies boardId semantics. Slightly above baseline.

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 (exports) and resource (a deck's slides) and output format (PNG files). Distinct from napkin_deck_outline/napkin_deck_compose siblings, and it explicitly clarifies it is image export, not PDF/PPT, routing to the File menu for those.

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 states when NOT to use it: 'For a PDF or PowerPoint, the user exports from the deck's File menu.' It also pre-empts outputs (what a single vs multiple slide result looks like) with concrete conditions.

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