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

With no annotations, the description carries the full burden. It usefully discloses two behavioral traits: the operation is confirm-gated (preview unless confirmed) and it processes no payment, which prevents a serious misread. It omits permissions/auth requirements and whether unlisting is reversible or affects existing buyers, leaving meaningful gaps for a mutation tool.

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 tightly written sentences with the action front-loaded ahead of the clarifying payment disclaimer. The parenthetical '(confirm-gated)' is slightly compressed, but nothing is padded or redundant.

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 5-parameter mutation tool with no annotations, no output schema, and 20% schema coverage, the description covers the core domain (marketplace listing, pricing, no payment) but leaves auth/permission context, currency semantics, and reversal behavior unexplained.

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 only 20% (just 'confirm'), so the description should compensate. It adds meaning for price ('set its price') and isMarketplace ('list or unlist'), but says nothing about currency, templateId, or the price/currency relationship, so the compensation is partial.

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 specific verbs (list/unlist, set price) and a specific resource (workout plan template on the Trainzilla marketplace), and clarifies the domain boundary by explaining this only makes the template buyable. An agent can distinguish it from update_workout_plan_template or list_workout_plan_templates without opening a 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?

Usage is implied by the description – you use this to put a template on the marketplace or take it off – but it never states prerequisites, when NOT to use it, or names a sibling alternative (e.g., set_diet_plan_template_marketplace for diets, update_workout_plan_template for content edits). Guidance is inferable rather than explicit.

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