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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, non-open-world), so the bar is lower. The description adds real context: rendering is done by a server-side browser, there is a hard 6-slide cap per call, selection prefers the first ids/ranges, and layout_warnings are returned from the same render.

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 core purpose, then constraints and parameter behavior. Dense but every sentence carries information; no filler or restatement of the name.

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?

Output schema covers return values, yet the description still usefully notes that layout_warnings accompany the pictures. For a read-only 6-parameter tool with full schema coverage and an output schema, this is complete enough to call correctly.

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 3 is the baseline, but the description goes further by explaining the precedence between slide_ids and from_number..to_number, the slide-1 default, and the meaning of width in px. This interaction logic is not captured in the per-parameter schema text.

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+resource (render PNG pictures of slides exactly as viewers see them) and the reason it exists (check text fits blocks, blocks don't overlap). An agent can distinguish this from siblings like check_layout or get_slide without opening any 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?

Clearly frames the use case (visually verifying layout correctness) and gives an operational constraint (max 6 slides per call). It does not, however, explicitly name the alternative check_layout tool or state when to prefer a programmatic check over a visual preview.

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