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

Annotations already declare idempotentHint=true and destructiveHint=false, but the description adds real behavioral context: the cross-system copy from Sightglass into Replo, and the concrete idempotency outcome ('copying the same creative again returns the existing asset'). It also discloses auth-relevant scoping indirectly via project/workspace. Return payload is noted, though side effects on the plan/charge are left to the schema.

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 short sentences, well front-loaded: purpose first, the key parameter caveat second, the return/idempotency behavior last. Every sentence carries information an agent needs.

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?

With no output schema, the description still explains the return value (asset id and URL) and the idempotent repeat behavior, plus the source/destination systems. For a 3-parameter, fully-documented tool with annotations covering the safety profile, nothing material 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 description coverage is 100%, so the schema already documents all three parameters including the creative.id-not-ad-id note. The description reinforces that same gotcha but adds no new parameter meaning (no format, defaults, or workspace requirement) beyond the structured fields.

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?

States a specific verb+resource (copy one ad creative's image) plus the source and destination systems (Sightglass → Replo project Assets). An agent can distinguish it from sightglass_get_ad, upload_asset and other asset/file tools without opening any schema.

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?

Explains the intent ('so it can be used as a reference in the project') and gives the critical usage caveat to pass the creative.id rather than the ad's own id. It does not name an explicit alternative tool or when-not-to-use, but the context for calling it is clear.

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