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

Annotations already cover read-only, non-destructive behavior. The description adds meaningful context beyond annotations: conditionsCel application logic, the extendDashboardConditions override, and that hidden series with visible: false are omitted from display.

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-loads the core action and scope, followed by behavioral detail and an example. Dense but appropriate for the tool's nuance; every sentence earns its place.

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?

Covers purpose, preconditions, the conditionsCel behavior, and a concrete example. No output schema exists, so it notes what is returned (series/timeSeries or comparison breakdown). Complete enough for correct invocation.

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 the baseline is 3. The description references widgetId and dashboardId in the example, but adds no semantics beyond what the schema descriptions already provide for slug, widgetId, and dashboardId.

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: 'Run a saved widget by id and return its cost data.' Clearly distinguishes itself from the query tool and the sibling get by explaining that no query config re-specification is needed.

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 says 'Use after get to get data for a specific widgetId,' and provides an example workflow. It does not name alternatives or exclusions (e.g., when to use query directly instead), so not a full 5.

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