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

Annotations already establish read-only, idempotent, non-destructive behavior, and the description adds real context beyond them: a hard cap of 50 lots, the fallback spot source (Bullion Price Check / gold-api.com), and that caller-supplied spot is labeled spot_source=caller in the answer. It does not discuss pricing staleness or failure behavior when a product name has no match.

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 tight sentences: the first front-loads what is valued and what is returned, the second carries the operational envelope (50-lot cap) and transport format. No filler despite a dense set of facts.

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?

With no output schema, the description does the work of naming the resulting figures (melt, dealer ask, gain vs melt, spot_source label), which is what an agent needs to decide the tool answers its question. Missing only edge-case behavior, such as what happens with untracked or ambiguous product names.

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 100%, so the baseline is 3; the description earns above that by documenting a REST serialization form (sku:qty[:cost_basis] comma-joined) that appears nowhere in the schema, and by clarifying that cost basis is what triggers the unrealized-gain computation. Spot parameters themselves are left entirely to the schema.

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?

Names a specific verb and resource (value a list of inventory lots of tracked products) and enumerates the outputs produced: melt value, median US dealer ask, cost basis and unrealized gain. It does not explicitly distinguish itself from near-siblings such as melt_value or true_cost, so it falls just 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 only implied: 'a list of inventory lots' and 'up to 50 lots' signal a batch valuation call, and cost basis being optional implies you pass it only when you want gain figures. No explicit when-to-use / when-not-to-use or named alternative (e.g. melt_value for a single item) is given.

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