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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: free tier returns redacted samples while PRO returns vendor/model names and exact prices, plus the per-unit pricing convention. Missing only things like pagination or result-size behavior.

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?

Front-loads coverage before distributions and ends with a useful unit convention, but the long parenthetical enumerations (vendors and pricing services, in total, by channel...) are dense and slow to parse.

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?

No output schema exists, so the description must characterize returns, and it does: counts/ranges/redacted samples for free, names and exact prices for PRO, plus unit semantics. Adequate for correct invocation, though filter behavior and result shape could be tighter.

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%, with both modality and _atom_api_key documented in-schema, so the description needn't restate them. The unit conventions (per 1,000 tokens, per image, etc.) are return-value semantics rather than parameter guidance, so no boost above baseline.

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: market coverage (vendors, pricing services, countries, models, SKUs, indexes) and price distributions by modality/unit/direction. Clearly distinct from siblings like compare_prices or get_price_history, though the verb is generic.

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?

Explains the free vs PRO tier split, which is a key usage consideration, but never states when to choose this over siblings such as get_index_benchmarks or compare_prices. Usage must be inferred from the return content.

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