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

Annotations already establish that this is a non-read-only, non-destructive, closed-world operation, and the description adds genuinely useful context on top: the copy is a distinct widget with a fresh embed code, and a pro copy consumes the plan's widget limit. That quota/licensing consequence is behavior an agent could not derive from the annotations. It stops short of saying whether the new widget id is returned or how the copy is identified afterward.

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?

Two sentences with zero filler, and the most decision-relevant facts (what gets copied, that the embed code is new, that it counts against the limit) come first. Nothing is repeated from the title or schema.

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 one-parameter, no-output-schema tool, the description covers what is duplicated, the identity of the result, and the billing/quota side effect. The only meaningful gap is the return value, which the absence of an output schema would otherwise require the description to explain.

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?

The single widget_id parameter is fully documented in the schema, including a pointer to list_widgets for discovery, so the schema carries the burden. The description adds no additional meaning about the identifier or any constraints on which widgets can be copied. Baseline 3 is appropriate at 100% schema coverage.

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 opens with a specific verb and resource ("Copies a widget") and scopes what is duplicated: settings plus accounts or review sources. It implicitly separates itself from create_widget by defining the copy as a new widget with its own embed code, though it never names the sibling alternatives explicitly.

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?

Usage is only implied: an agent can infer this is the tool for duplicating an existing widget rather than building one from scratch with create_widget. There is no explicit when-to-use guidance, no stated preconditions, and no note about when copying is preferable to re-creating or updating a widget.

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