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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds behavioral value by explaining that paid modules require an active entitlement and that not-entitled responses return a {locked, teaser, checkout_url} shape. 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?

The description is two tight sentences with no filler. It front-loads the primary action and then adds the entitlement outcome, ensuring every sentence 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?

Given the output schema exists and annotations cover safety, the description is largely complete: it states the resource, the access rule, and the fallback return shape. The main gap is the lack of parameter explanation, but that is already penalized in parameter semantics; overall, an agent can select and invoke the tool for common cases.

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 must compensate, but it does not explain any of the four parameters (course, module, section, auth_token). It only indirectly references 'module,' leaving the meaning and expected values of all parameters unclear.

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 opens with a specific verb+resource: 'Fetch a module's lesson content,' which clearly identifies what the tool does and distinguishes it from sibling tools like get_outline and get_recap. It also adds the entitlement context, making the purpose even more concrete.

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 implies when to use the tool—when a module's lesson content is needed—and provides an important condition: free modules are open, while paid modules require entitlement. It does not explicitly name alternatives or exclusions, but the context is clear enough for typical use.

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