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

Annotations already carry the safety profile, and 'Free, read-only' merely restates readOnlyHint, which earns no credit. The valuable addition is disclosing that the tool returns prompts and a plan (7-image gallery, edit-from-packshot prompts, ad sizes, claims rules, estimated cost) rather than generated images — a non-obvious behavioral fact for a tool whose name suggests image creation.

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?

It is front-loaded with the core action, but the rest is one run-on sentence with nested parentheses and ellipsis lists that is hard to scan. The trailing 'Free, read-only' duplicates structured annotations and does not earn its place.

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 enumeration of deliverables is what makes this tool callable with correct expectations, and it covers composition, platform rules and cost. Enough is present; only the prompt/target-model handoff for downstream generation is left implicit.

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 baseline applies and the schema already defines item, country, product, variants and marketplace. The description adds nothing about how the two product-ish parameters (item vs product) interact or what marketplace selection changes — the one real ambiguity left unaddressed.

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?

Opens with a specific verb and scope ('Plan the product image set for one market') and enumerates the concrete deliverables, so an agent can tell this apart from video_studio or channel_plan. It stops short of naming a sibling or state of work it is not, which keeps it at 4 rather than 5.

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 trigger condition is implied by 'for one market' and the required country parameter, and 'Free, read-only' signals a safe planning call. There is no explicit when-to-use/when-not guidance and no routing to alternatives such as video_studio for motion assets, so usage must be inferred.

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