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

No annotations are present, so the description carries the burden. It discloses non-obvious operational behavior: the asset must already exist at a specific path, the upload mechanisms, and the fact that reusing a filename creates a new layer with a fresh id rather than overwriting. It does not mention error cases or stacking order, but the main side effects are adequately surfaced.

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 sentences with the primary action front-loaded, followed by the required asset context and the duplication rule. The long second sentence is information-dense and every clause earns 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?

The tool is a mutation with nested optional semantics, but the schema fully documents the parameters and the description covers the non-obvious asset prerequisite and duplication behavior. There is no output schema, so an explicit return-value note would be a minor improvement; otherwise the agent has enough to invoke correctly.

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 schema already documents all 7 parameters thoroughly (100% coverage). The description adds filename-specific meaning: the asset must be pre-uploaded to a known path, and duplicate layers are created by reusing a filename — details not inferable from the schema alone.

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 "Add an image layer" — a specific verb and resource, and the asset-type scope distinguishes it from sibling tools like add_text_layer, add_video_layer, and add_shape. The duplication note adds a secondary use case without blurring the primary purpose.

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?

Clearly describes the required precondition (asset must already exist), gives specific upload routes, and explains the duplicate-layer path by reusing a filename. It does not explicitly name sibling alternatives, but the context makes it clear when this tool applies.

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