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

Annotations already cover the read-only, idempotent, non-destructive safety profile, so the description adds genuinely new behavioral facts: daily granularity, single-source scope, a plan-dependent history window, and a fixed cost of 3 credits. It stops short of describing return shape or how sparse/partial series are handled.

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 short sentences with zero filler; the core scope is front-loaded and the cost note is appended compactly.

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 an 8-parameter tool with no output schema, the description says nothing about the returned series structure, granularity of missing days, or the interplay between market_language, condition, and source. It is adequate to start a call but leaves meaningful gaps.

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 88%, so the schema already documents source, card_id/sealed_id mutual exclusivity, variant, condition, and the date defaults. The description only reinforces 'one source' and 'card or sealed product', adding marginal meaning beyond the structured fields.

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 resource and scope: 'Daily price history of one source for a card or a sealed product'. The word 'history' implicitly separates it from sibling tools like get_card_prices and compare_prices, though no sibling is named explicitly.

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?

The phrase 'bounded by the plan's history' signals a real constraint on when results are available, and the credit price hints at cost sensitivity, but there is no explicit when-to-use / when-not guidance or named alternative such as get_card_prices for current values.

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