co_list_layers

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

Annotations already reveal readOnlyHint/idempotentHint/destructiveHint, so the description only needs to add behavioral detail beyond safety. It adds valuable context: layers lack ids and are accessed by index, with the background layer fixed at index 0. This goes beyond what annotations provide and helps agents reason about addressing.

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 deliver the core purpose, layer atypical identity, and addressing scheme without filler. The most important information is front-loaded, and no words are wasted.

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?

Although the description thoroughly explains what a layer looks like and its index-based identity, it omits parameter semantics. Since there is no output schema and no explanation of the two parameters, the agent is left without crucial invocation information. The description is adequate for a simple idealized read but not complete enough for a real tool call.

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 0%: neither `variant_ids` nor `use_current_selection` are described in the schema or the tool description. The description refers to 'variants' but does not explain the parameters, their roles, defaults, or interplay such as when one vs. the other is used. With two parameters and no property descriptions, an agent has to guess how to fill out the request.

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 starts with a specific action, 'List the layers on variants', and names the output fields (kind, enabled state, opacity, luma-range settings). It clearly distinguishes this from sibling tools like co_list_variants by focusing on layers, and adds useful identity details (no id, index addressing, background at index 0).

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 description implies usage on variant layers and indicates that layers are addressed by index, but it does not explain when to prefer this over alternatives like co_get_variant, nor does it mention exclusions. There is no explicit 'when to use this vs. that' guidance, only the implied context of variants having layers.

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