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

Annotations already declare idempotentHint=true and destructiveHint=false, and the description reinforces this with a concrete consequence: 'copying the same creative again returns the existing asset.' It also discloses the return payload (asset id and URL), which the annotations do not. It omits any mention of permissions or plan implications, which are instead buried in the schema fields.

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 tight sentences: what it does, the critical parameter caveat, and the return/idempotency behavior. Every sentence earns its place and the core action is front-loaded.

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 three-parameter, single-purpose copy tool with no output schema, the description covers the action, the source-to-destination flow, the id-caveat, and the return shape. Nothing an agent needs to invoke it correctly is missing.

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 all three parameters are already documented in detail, including the workspace-plan behavior and the creative.id caveat. The description only restates the creative.id constraint, adding no syntax, format, or precedence information beyond what the schema provides. 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 gives a specific verb and resource ('Copy one ad creative's image from Sightglass into the Replo project's Assets') plus a clear motive ('so it can be used as a reference'). It implicitly separates itself from upload_asset by naming the Sightglass source, but never explicitly contrasts with the closest siblings.

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 stated purpose ('used as a reference in the project') supplies the condition for choosing this tool, and the note about using `creative.id` rather than the ad id preempts a common misuse. It stops short of naming alternatives such as upload_asset or find_assets, so there is no explicit when-not guidance.

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