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

Annotations already declare destructiveHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely new context beyond them: removal from this user's watch list, cessation of further weekly charges, and that the call is free. It does not say whether removal is reversible, which is the one remaining behavioral gap.

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, zero waste, with the routing rule and the key consequence (no further charges) front-loaded. Nothing is restated from the title or schema.

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?

With no output schema and full annotation coverage, the description supplies what is missing: what gets removed, the billing effect, and the cost. The marketplace parameter is never mentioned, a minor omission for a 3-param tool.

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 100% so the baseline is 3, but the description adds meaning the schema does not: asin and store_url are alternatives keyed to resource type, and the schema enforces no oneOf/required constraint even though the operation needs one of them. This compensates for the missing mutual-exclusivity rule.

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 ('Stop watching') and two concrete resources (Amazon product, Shopify store), and the parenthetical maps each resource to the parameter that selects it. Against siblings watch_add/watch_list the inverse relationship is immediately obvious.

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?

Gives clear conditional routing: 'pass asin' for Amazon, 'pass store_url' for Shopify, which is exactly the decision an agent must make. It does not explicitly name watch_list/watch_add as alternatives or state prerequisites (e.g. the item must currently be watched), so it stops short of a 5.

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