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

Annotations declare readOnlyHint=false and destructiveHint=false, so it's a mutating but not destructive operation. The description adds one behavioral detail: position, width, and height use sensible defaults, which clarifies that these are optional and will be auto-set. However, it doesn't mention side effects, required permissions, or what happens on failure. This is minimal but not contradictory.

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 a single, efficient sentence that front-loads the purpose and adds a useful note about defaults. Zero wasted words, well-structured for quick parsing.

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 create-operation with 5 parameters and an output schema, the description is minimal. It covers the core action and the defaults behavior, but lacks usage guidance and behavioral nuance. The schema and output schema handle parameter details and return values, so this is adequate but not rich. Given the tool's relative simplicity, a 3 is appropriate.

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 description coverage is 100%, so all parameters are documented in the schema. The description adds nothing about parameter meaning or relationships; it only mentions defaults for properties not in the schema. This meets the baseline but doesn't enhance understanding beyond the schema.

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 'Add an embed widget to a page', a specific verb and resource. It distinguishes the tool from other add_*_widget siblings by naming the widget type, though it doesn't explicitly contrast with them. The defaults comment adds context but doesn't affect purpose clarity.

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?

No guidance on when to use this tool vs alternatives like add_button_widget or add_image_widget. It doesn't mention prerequisites (e.g., that page_id and client_id must come from list_pages/list_clients, though schema hints at this) or when this tool would be inappropriate. The description provides no explicit usage conditions or exclusions.

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