pbi_page_building_blocks

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

With readOnlyHint=true in annotations, the safety profile is already covered. The description adds behavioral context by specifying that it returns the model schema, visual catalog, and canvas/pages, and that it reveals available fields and visual types. It doesn't contradict the read-only annotation and provides useful information about the tool's output scope.

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?

The description is two sentences, both purposeful. The first enumerates the deliverables, the second gives precise usage timing. There is no redundant or filler content. It is fully front-loaded and easy to parse.

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 tool with no parameters and an output schema, the description adequately covers purpose, content, and usage timing. It explains what the agent will get (model, visuals catalog, canvas/pages) and when to call it (before proposing a page). The output schema is available to fill in return structure details, so the description is sufficiently complete.

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 tool has zero parameters, so there is nothing to add beyond the schema. Per the rubric, 0 parameters earns a baseline of 4. The description doesn't need to describe parameter semantics, and it adds no irrelevant details.

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 clearly states the tool 'delivers the material for designing a page' and enumerates its contents: model (tables/measures/columns), catalog of existing visuals, canvas, and pages. It distinguishes itself from sibling tools by positioning itself as a pre-design resource that tells you what fields and visual types are available, not just listing individual tables or measures.

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 explicitly instructs to use this tool 'BEFORE proposing a page' and explains what it provides (fields and visual types). This gives clear contextual timing, though it doesn't name specific alternative tools or explicit when-not-to-use scenarios. The guidance is actionable and concise.

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