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

Beyond the readOnlyHint annotation, the description discloses concrete behavior: no generation occurs, the default output is 6 slides at 4:5, the slide structure is hook/in-the-life stills/soft CTA, and screenshot compositing is controlled by hasScreenshot. This meaningfully exceeds the annotation-only picture.

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 with no filler. The core purpose and key exclusions come first, then defaults and parameter behavior. Every sentence adds necessary information.

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 read-only quoting tool with an output schema, the description covers what the tool does, what it does not do, default behavior, and the one parameter that materially changes output. An agent has enough to select and invoke it 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?

The input schema already covers all parameters at 100%, so the baseline is 3. The description adds real value by specifying the default slide count, aspect ratio, slide composition, and tying niche to the stills content, which is more than incidental restatement.

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: 'Quote an Ad Lab Proof pack.' The explicit 'Does not generate' immediately distinguishes it from the sibling generate_ad_proof_pack, so an agent can tell it apart without inspecting either 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?

The description clearly implies this tool is for quoting rather than generating, and 'Does not generate' is a useful exclusion. It also gives parameter-level guidance for hasScreenshot. However, it does not explicitly name an alternative such as generate_ad_proof_pack for the generation case.

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