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

The annotations already declare read-only, idempotent, non-destructive behavior. The description adds useful operational context beyond those annotations: it requires a Word Orb key, counts against quota, and warns that content availability varies. This is helpful transparency for an agent anticipating failures or costs.

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 main purpose and followed by availability and access constraints. Every sentence adds distinct value 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?

The description omits important selection semantics: the schema declares zero required parameters while the description implies all three (day, track, age) are used. It also does not describe the shape of the returned lesson or what happens when content is unavailable. For a tool with no output schema and no parameter documentation, this is incomplete.

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%, so the description bears the burden of explaining the parameters. It only restates that the lesson is 'for a day, track and age group' without defining value semantics, ranges, or behavior when parameters are omitted. The input schema's enums and bounds carry most of the meaning.

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 states a clear verb and resource: 'Retrieve an available structured lesson' and specifies the selection dimensions (day, track, age group). It is distinguishable from siblings like get_quiz or lookup_word by the resource type, though it does not explicitly differentiate from get_quiz.

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?

No when-to-use or when-not-to-use guidance is provided, and no alternative tools are mentioned. The only practical note is 'Content availability varies,' which warns about failures but does not help an agent decide between this and get_quiz or other sibling tools.

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