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

Annotations already declare read-only, idempotent, and non-destructive behavior; the description adds useful behavioral context beyond that, including the moderate token cost (1-3k tokens) and the kind of page returned. There is no contradiction with 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?

Two sentences with no filler: the first front-loads the action, resource, and content; the second adds only the relevant use case and cost. Every word earns its place.

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?

For a simple read-only overview tool with an output schema, rich annotations, and fully documented parameters, the description covers purpose, when to use it, and cost. Nothing material needed by an agent to select or invoke it correctly is missing.

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 fully documents subjectSlug, unitSlug, and intent, including source guidance ('from get_subject_outline', 'Use list_subjects'). The tool description contributes no additional parameter meaning, which is acceptable at the baseline of 3.

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 names a specific verb ('Returns') and resource ('overview page for one unit of an AP course') and enumerates the contents: coverage, exam weighting, topics, and study plan. It is clearly distinguished from sibling tools like get_subject_outline or get_study_guide by being scoped to a single unit's overview.

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?

States when it is suitable: 'when a student is reviewing a whole unit,' providing clear context. It doesn't explicitly name alternatives or when-not-to-use, but the use case is well enough defined to route an agent appropriately among the listed siblings.

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