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

With no annotations, the description carries the full behavioral burden and does well: it discloses that the tool is FREE, updated daily, merkle-committed on GradedPriceOracle, and explicitly states the price basis (eBay asks). This adds meaningful behavioral context beyond a simple 'get' tool, though it does not mention any side effects or auth requirements (likely read-only).

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?

The description is a single, dense sentence that front-loads its core purpose and packs in useful details (data basis, freshness, cost, oracle). It is efficient and avoids fluff, though it might be slightly run-on with multiple clauses; still appropriately sized for the information conveyed.

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 that an output schema exists, the description doesn't need to explain return values. It explains the purpose, data basis, and operational traits well. However, it fails to explain the sole input parameter (product_id), which is a critical omission for a 1-parameter tool. This leaves the definition incomplete for correct invocation.

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?

The input schema has only one parameter, product_id, with 0% description coverage. The tool description mentions 'for one card' but never explicitly maps product_id to a card identifier or explains what value to pass. The description focuses entirely on the output, leaving the only required parameter completely unexplained, which fails to compensate for the schema gap.

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?

The description states a specific resource and action: 'Graded-slab ASKING prices for one card' and enumerates the exact outputs (PSA/BGS/CGC medians, listing counts, low/high, as-of, price_basis). It clearly distinguishes itself from siblings by emphasizing 'eBay asks, not sold prices' and positioning itself as the LIVE value layer, separating it from raw-card price tools.

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 description offers clear context for when to use this tool ('the LIVE value layer while the USD raw-card panel is frozen' and 'the basis of the graded-slab loan terms'), implying it is the go-to for graded-slab ask prices. However, it does not explicitly name alternatives or exclusions, so it falls short of a 5.

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