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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the agent knows this is a mutating but not destructive operation. The description adds no behavioral context beyond the schema—no mention of whether existing settings are replaced, whether the update is partial or full, or any side effects. With annotations covering the basic safety profile, a 3 is fair.

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 short sentence that is front-loaded and free of fluff. It earns its place by naming the specific widget type, though it could arguably be even more informative without becoming verbose.

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 simple update tool with a full schema and an output schema, the description is minimally adequate. However, it doesn't clarify whether the update replaces the entire embed configuration or just the provided fields, and it doesn't mention any constraints (e.g., whether link_url and embed_type must be provided together). The output schema exists, so return values are covered, but the behavioral gap keeps this at a 3.

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 the schema already documents all three parameters (id, link_url, embed_type) with descriptions. The tool description adds no additional meaning beyond what the schema provides, so the baseline 3 applies.

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 'Update an EMBED widget.' clearly identifies the verb (update) and resource (EMBED widget), distinguishing it from other update_*_widget siblings like update_button_widget or update_text_widget. However, it doesn't elaborate on what aspects of an embed widget can be updated beyond the schema, and the capitalization of EMBED is stylistic rather than informative.

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 implies usage by naming the resource type, and the schema's required 'id' field (from list_widgets) gives a hint about how to target the widget. But there is no explicit guidance on when to use this tool versus alternatives like update_data_widget or add_embed_widget, nor any mention of prerequisites or context.

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