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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered by structured data. The description adds the daily cadence and single-metal scoping, but says nothing about ordering, rate limits, or how the cursor/results relate to each other beyond what the schema already documents.

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?

A single front-loaded sentence with zero filler; the resource and scope appear immediately. It is arguably too terse for a six-parameter tool with pagination and format modes, but nothing in it is wasted.

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 shape needn't be described, and annotations cover the read-only profile. However, for a paginated 6-parameter tool, the description omits result ordering, the default window behavior, and any routing against sibling price tools, leaving an agent to infer more than it should.

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 83% and the schema documents base, days, limit, cursor, format, and the metal enum thoroughly. The description only reinforces the single-metal selection ('one metal or the Goldback'), adding marginal value over the schema, so it sits at the baseline for high coverage.

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+resource ('Daily historical series') and scopes it to 'one metal or the Goldback,' so the agent understands it returns one time series rather than a batch quote. It does not name a sibling (e.g. get_spot_prices) to draw the live-vs-historical line explicitly, so it falls short of full sibling differentiation.

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?

'for charting' implies the intended use case and 'Daily historical series' implicitly contrasts with live spot pricing, but no alternative tool is named and there is no when-not guidance. Usage is inferable rather than stated.

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