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

No annotations are provided, so the description carries the full burden. It adds useful behavioral context by stating 'active' (filtering only active services) and 'live' (real-time database source). However, it does not disclose the read-only nature, potential side effects, or any limitations such as pagination or required permissions, which would be expected given the absence of annotations.

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?

The description is a single, well-structured sentence that front-loads the main action and resource. Every word adds value, and there is no redundant or filler content. It is appropriately sized for the tool's simplicity.

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 simple and has an output schema, so the description does not need to explain return values. It clearly states the purpose, target coach, and data source, making it mostly complete. However, the lack of parameter explanation and explicit usage guidance relative to siblings slightly reduces completeness, though the output schema compensates for return-value details.

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 has 2 parameters with 0% description coverage, and the description does not compensate. It mentions 'for a coach' which loosely maps to coach_slug, but it completely ignores the language parameter. There is no explanation of parameter formats, defaults, or how they affect the output, leaving the agent with insufficient information.

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 uses a specific verb ('List') and identifies the resource ('active lesson services and prices for a coach') plus the source ('live Voice School database'). This clearly distinguishes it from sibling tools like create_lesson_request (creation), search_lesson_availability (availability search), and voice_school_info (general school info).

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 for when to use this tool: to retrieve active lesson services and prices for a specific coach. It does not explicitly mention alternatives or exclusions, but the sibling tool names make the distinctions obvious, so the context is sufficient without overt when-not-to-use guidance.

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