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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=false, so safety is covered. The description adds genuinely new operational context: a $0.10 cost and an API-key requirement, which an agent needs before calling. It does not describe pagination or volume limits, keeping it from a 5.

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 compact sentences, front-loaded with the purpose, followed by the cost/auth caveat. Every fragment carries information; nothing is redundant with the title.

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?

An output schema exists, so return-value description is unnecessary, and the schema documents the sole parameter fully. The description supplies ordering, cost, and auth context, leaving only minor gaps like result limits or whether history can be empty.

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?

Only one parameter and schema description coverage is 100%, with the schema already explaining the id comes from add_inventory_item, get_inventory, or search_inventory. The description adds 'owned' as a qualifier but no syntax or format detail, so baseline 3 is appropriate.

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?

Specific verb+resource: returns chronological valuation history for a single owned inventory item. It clearly reads as a read-side counterpart to add_inventory_valuation and distinct from get_inventory/get_inventory_item. It stops short of explicitly naming the siblings it differs from, so a 4 rather than 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 'one owned Inventory item' – the caller must already have an item id, implying use after add_inventory_item/get_inventory/search_inventory. There is no explicit when-to-use-vs-alternative statement or exclusion (e.g., when to prefer this over get_inventory_item).

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