list_music_models

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds real behavioral context beyond them: pricing_status is independent and 'prices never filter model visibility,' which tells the agent to expect models with non-available pricing to still appear, plus the default_mv behavior. It doesn't cover pagination or refresh/rate-limit behavior.

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, front-loaded with the core action and scoping rule. The hardcoded 'v6-pro, v6-wild-pro, v6-mini' list earns its place as a routing hint but is the kind of version-specific detail that goes stale and could have been summarized.

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 carries the burden of describing returns, and it does cover the key fields (capabilities, pricing_status, default_mv, mv values). It leaves the shape of 'capabilities' unspecified, which is a modest gap for a zero-parameter catalog tool.

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 tool takes zero parameters, so per the rubric the baseline is 4. The description correctly adds no parameter discussion, and the embedded 'Current mv values' enumeration is a value-domain hint rather than a parameter specification.

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 the complete current Web music catalog') and names the payload contents (capabilities, pricing_status). The 'music' qualifier plus the mv enumeration cleanly separates it from sibling listers like list_image_models, list_tts_models, and list_video_models.

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?

Gives explicit downstream guidance: 'When the user has not specified a model, use the returned default_mv.' It also implies why you'd call this tool (to discover models and their pricing before estimating/generating). It stops short of naming an alternative tool or an explicit when-not-to-call condition.

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