create_central_visual_prompt

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

The annotations only declare readOnly/destructive/openWorld, so they say nothing about the division of labor. The description adds the crucial behavioral fact that this tool emits a prompt rather than pixels and that generation, inspection, and file saving are the caller's responsibility. It doesn't cover permissions, rate limits, or the shape of the returned prompt, leaving some residual uncertainty.

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, each earning its place: what it produces, what the caller must do next, and what it explicitly does not do. The core purpose and the negative capability are front-loaded with no filler.

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?

The description covers the input source and the downstream hand-off well, which matters for a tool embedded in a larger pipeline. However, with no output schema and a large nested input schema, it never states what the tool actually returns (presumably a prompt string with an alt text) or how the generated prompt is scoped to the topic. That leaves an agent guessing about the response it must act on.

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?

There is a single 'content' parameter but it is a deeply nested object with many required subfields (headline, cards, callouts, statistic, takeaway, centralVisual) at 0% schema description coverage. The phrase 'from the full one-pager content' implies the whole one-pager document is passed, but the description never explains which fields drive the prompt or what centralVisual.concept, useReferenceImage, and heroImage are for. It does not compensate for the coverage gap.

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?

The description names a specific verb and artifact ('Prepare a topic-specific image-generation prompt') and a specific source ('from the full one-pager content'), and it explicitly negates the most likely misreading with 'Does not generate pixels itself.' It also ties the artifact to the downstream consumer (heroImage passed to create_one_pager), which distinguishes it from the other prompt-generation siblings.

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?

It gives concrete when-to-use context: call this to produce the central visual prompt for a one-pager, then generate and inspect the image externally, save it in inputs, and pass heroImage to create_one_pager. That is a clear workflow. It stops short of explicitly contrasting itself with siblings like create_one_pager_visual_prompts or create_generation_prompt, so an agent must infer which prompt tool applies when.

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