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

Although annotations already declare destructiveHint=true, idempotentHint=true and readOnlyHint=false, the description adds genuinely non-obvious behavior: that Order Desk's PUT replaces the whole record, so the tool internally reads, applies only the passed fields, and writes the full record back, with metadata and variation keys merged rather than replaced. This merge-vs-replace nuance is exactly the kind of context annotations cannot convey.

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 definition is well front-loaded: an operation-type prefix, then purpose, then the critical merge semantics, then the endpoint. Every sentence carries weight, though the final 'PUT /inventory-items/{inventory_item_id}.' line is largely redundant with the schema's required id.

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 destructive 11-parameter mutation tool with no output schema and only 45% schema coverage, the description supplies the most decision-relevant behavior (partial-update merge semantics, whole-record replace risk). It stops short of stating permissions, reversibility guarantees, or error behavior, which would complete the picture.

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 only 45% across 11 parameters, so the description must partly compensate; it does so for the important cases by explaining that metadata and variation_list keys are merged rather than overwritten, and by exemplifying 'stock'. The remaining fields (code, cost, name, price, weight, location) get no additional meaning beyond what the schema minimally provides.

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 states a specific verb and resource ('change fields of an inventory item') with a concrete example ('stock count'), and the 'WRITE:' prefix immediately signals mutation. It implicitly separates this from the get/list/create siblings through the word 'change', but never names an alternative tool explicitly, keeping it short of a 5.

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 'change fields of an inventory item', so an agent can infer this is the edit path rather than create/get/list. However, there is no explicit when-to-use guidance, no prerequisites, and no named alternative such as create_inventory_item for new items, leaving routing to inference.

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