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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine behavioral value by disclosing that results include can_write and that model-scoped API keys return only the bound model. This goes beyond the structured annotations without contradicting them.

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 focused sentences, each earning its place: the core action, the can_write field semantics, and the scoped-key special case. The most important information is front-loaded, and there is no filler.

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?

This is a simple, read-only, zero-required-parameter list tool. The description covers the operation, access scope, result flag, and scoped-key behavior. No output schema exists, but the description says enough about the result shape for an agent to call it confidently; pagination or full field enumeration would be nice but are not essential.

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 fully documents q and writable, including wildcard behavior and omission semantics. The description does not need to repeat parameter details, so the 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?

States a specific verb and resource: 'List models the authenticated user can access.' It clearly distinguishes itself from get_model and other layerz_list_* siblings by focusing on the models the caller can access. The title and description align, and the description adds useful scope.

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 provides clear context: this is the tool for listing accessible models, with optional can_write information. It does not explicitly compare itself to get_model or list_templates, so alternatives are not named, but the list-vs-get distinction is strongly implied and the context is clear.

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