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

Annotations declare a non-readonly, non-idempotent, non-destructive create, and the description adds real behavioral context beyond that: what is inherited (recipes, notes, history) versus what is new (roast date, weight, price, state), plus the bag_id return and that bag numbers are a separate series from bean numbers. It stops short of covering failure modes or duplicate handling, but the inheritance/no-active-change details are the valuable part.

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?

Four short sentences, front-loaded with the core action before the inheritance rule, the return-value caveat, and the alternative. Nothing repeats the name or the schema, and every sentence carries information an agent needs.

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 16-parameter create tool with annotations and an output schema, the description covers the essential gap areas: which entity is being extended, what is conserved, the id semantics of the return, and the sibling to use instead. Remaining detail (formats, defaults, optional fields) is delegated correctly to the schema.

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 69% and the schema already documents the dates, state default, bag_notes scoping and product_id guidance, so the baseline is a 3. The description does add a useful partition by naming the 'purchase facts (roast date, weight, price, state)' that are new per bag, but it leaves the remaining undocumented fields (ean, cost, storage, currency) untouched.

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 ('Register another bag of a coffee that is already in list_beans') and pins the scope to a repeat purchase of the same roaster's product. It explicitly distinguishes itself from register_coffee, so an agent can choose without opening either 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?

Gives both the when ('coffee already in list_beans... bought again') and the when-not with a named alternative ('For a coffee that is not in list_beans yet, call register_coffee instead'). It also rules out a side effect an agent might assume ('Does not change the active coffee').

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