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

Annotations already flag destructiveHint=true and idempotentHint=true, but the description adds the concrete consequences: it 'Replaces any quantity previously recorded for that item', i.e. what gets overwritten and for which scope. It does not state permission/auth requirements or failure behavior, so it extends rather than fully carries the burden.

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 sentences, front-loaded with the purpose and the driving sibling, then the item domain, then units and overwrite semantics. No filler; every clause 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 3-required-param mutation with no output schema, the definition covers domain values, units, and replace semantics, and annotations cover safety. Only minor gaps remain (accepted unit string formats, whether an item can be cleared, auth expectations).

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 compensate, and it does: it enumerates legal `item` values (nappies, wipes, formula, vitamin_d, milk) and per-item unit conventions (counts, g/kg, doses, litres/ml/gallons/fl_oz). It is not exhaustive on accepted unit spellings or whether quantity must be non-negative, leaving some ambiguity.

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 ('Record how much of a consumable is currently on hand') plus the downstream consumer (get_restock_forecast), which distinguishes it from the log_* event siblings and get_restock_forecast itself. An agent can pick 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?

It frames the purpose in terms of the sibling it feeds (get_restock_forecast), giving clear usage context for a stock-level snapshot vs. logging individual events. It stops short of an explicit when-not or a named alternative (e.g. 'do not use this to log a single nappy change; use log_nappy').

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