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

Discloses that the tool applies the dashboard's conditionsCel unless extendDashboardConditions=false, and that it returns the same series/timeSeries or comparison breakdown as the query tool. Annotations already cover read-only/non-destructive behavior, so this adds meaningful context without contradiction.

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 longer than strictly necessary but front-loaded with the main action and includes a helpful example. Every sentence contributes functional or usage information, so no waste.

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?

With no output schema, the description compensates by specifying the return format ('same series/timeSeries or comparison breakdown as the query tool') and the workflow. It doesn't detail error cases or edge conditions, but for a 3-param tool this is adequate.

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 already provides 100% parameter coverage, but the description adds value by noting widgetId comes from get/get_context, explaining dashboardId's role in applying conditionsCel, and providing an example mapping natural language to arguments. This exceeds bare schema labels.

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 uses a specific verb ('Run a saved widget') and resource ('by id and return its cost data'), clearly differentiating it from sibling tools like get_dashboard_widget_image (image) and query (ad-hoc). It also states the return format matches the query tool, providing strong semantic distinction.

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 instructs 'Use after get to get data for a specific widgetId' and gives a concrete example flow. It doesn't enumerate when NOT to use, but the workflow context and relationship to the query tool make usage clear.

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