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

With only generic annotations (readOnlyHint false, destructiveHint false), the description carries the burden and does it well. It discloses the important behavioral traits: no datasource, no fetching, inline content, defaulting to 0 when value is omitted, and that dimensions match the editor's card. This adds substantial context beyond the annotations.

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 sentences deliver meaningful, non-redundant information. The action is front-loaded, the key differentiator is stated early, and every sentence adds value—examples, behavior, and layout context.

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?

Given the schema fully documents all parameters and required IDs, and an output schema exists for return values, the description covers the remaining context: what the widget is, how it behaves, how to set or omit the value, and how to update it later. Nothing critical is missing 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 a baseline of 3 applies. The description goes beyond the schema by explaining the 'value' parameter's semantics with concrete examples, the default-to-0 behavior, and the later update path, which helps the agent understand how to use the parameter correctly.

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 verb and resource: 'Add a Static Value widget to a page', with explicit examples of the value types it accepts. It also distinguishes this widget from other cards by emphasizing 'has no datasource and never fetches' and 'its content is inline', making it easy to separate from sibling add_*_widget tools.

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 gives clear context by contrasting this widget with 'the other cards' and explains how to set the value now or later via update_static_value_widget. It does not explicitly name alternative tools or state exact when-not-to-use conditions, so it stops just short of full exclusion guidance.

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