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

Annotations already declare the mutation's destructive and idempotent nature, but the description adds valuable operational context: partial update semantics ('Omitted fields stay unchanged'), invalid null values, tier quotas on activation, and timeout uncertainty with a retry recommendation. These details go beyond structured annotations and help an agent avoid common pitfalls.

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 front-loaded with the core action and every sentence adds distinct value: partial update behavior, validation, quota constraints, and timeout handling. There is no filler or repetition, and it is appropriately sized for a mutation tool.

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 presence of annotations and an output schema, the description covers the essential behavioral aspects (partial update, validation, quota, timeout) needed to invoke the tool correctly. It only misses explicit mention of the required productListingId and any permission prerequisites, but otherwise is complete.

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 carry parameter meaning. It clarifies the purpose of notifications, state, currency, and language fields, but it never explains the required productListingId parameter or its format, leaving a gap for a critical input.

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 uses a clear verb ('Update') and specifies the resource (watchlist notification setting or state) and the return (personalized listing). It distinguishes the patch operation from siblings like addWatchlistProduct and deleteWatchlistProduct by focusing on modification, though it doesn't name those siblings explicitly.

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 usage by stating what can be updated and constraints (e.g., omitted fields unchanged), but it never explicitly says when to use this tool versus alternatives like addWatchlistProduct or deleteWatchlistProduct. An agent must infer the appropriate context from the verb.

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