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

Adds value beyond annotations by disclosing data provenance ('real sold listings, refreshed daily') and geographic/currency context (USD market values), which annotations don't cover. Annotations already declare read-only/idempotent safety, so the remaining gaps (e.g., how stale a card is) are minor.

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?

Three tight sentences, front-loaded with the trigger condition, then the data scope, then the exclusion. Every sentence carries distinct information with no filler.

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?

Given an output schema is present, the description needn't explain return shape; it covers trigger, prerequisites, data provenance, and exclusion. An agent has everything needed to select and invoke correctly.

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% and the schema itself documents card_id format with examples. The description reinforces the dependency ('Requires a card id from search_cards') but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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 precise verb+resource ('full current value of a specific card') and enumerates exactly what is returned: ungraded by condition and graded by company/grade. Distinguishes itself from siblings like search_cards and get_price_history by scope (full ladder vs. history vs. name search).

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?

Explicitly states when to use it ('user wants the full current value') and when not to ('Do not use to search by name'), and names the prerequisite source for the card id (search_cards). Routing is unambiguous.

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