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

With no annotations, the description carries the full behavioral burden, and it does disclose the important traits: 'Public read' (no auth required) and 'active' only (inactive packs excluded). It omits ordering, pagination, and what happens for an unknown slug, which matter for a list endpoint.

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 purpose, then return fields, then usage context. No filler and no repetition of the tool name.

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?

There is no output schema, so enumerating the returned fields (name, sessionCount, priceCents, currency, validityDays) is valuable and covers most of what an agent needs. Remaining gaps are minor: result ordering, empty-result behavior, and pagination for mentors with many packs.

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 coverage is 0% and the single parameter has no description in the schema. The phrase 'by slug' and 'a mentor's ... packs' implies mentorSlug identifies a mentor rather than a class, which is genuinely useful disambiguation, but no format or example value is given.

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 with scope qualifiers: 'List a mentor's active class packs by slug.' The 'active' filter and mentor-scoping are explicit, and no sibling tool (search_classes, get_mentor, get_class_payment_methods) covers class packs, so an agent can distinguish it without opening the schema.

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?

Provides concrete usage context: 'useful when a client asks what packs does X sell?' and 'before calling buy_class_pack', which names the downstream tool this feeds. It gives no explicit exclusions or note about inactive/expired packs beyond the word 'active', so it stops short of full when/when-not guidance.

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