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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful output context (the good-price assessment, 90-day average, lowest recorded price), but says nothing about rate limits, data freshness, or what happens for a deal with sparse history.

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 that begins with the resource and wastes no words. It is efficient, though the comparative clause is slightly dense and unpacks only on a second read.

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?

With no output schema, the description does the right thing by summarizing the return payload. However, it omits where a deal_id comes from (get_deal/search_deals), gives no sibling routing, and leaves two of three parameters unexplained – gaps that matter for a tool with no documented output contract.

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 only 33% – only 'market' is documented, and that documentation is largely redundant with its single-value enum. The description does implicitly tie the '90-day average' to the days parameter default, which helps, but it says nothing about the required deal_id or how the days window changes the assessment.

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?

Names a specific verb+resource ('Price history for a deal') and adds the analytic angle ('Is this a good price?' vs. 90-day average and lowest recorded price), which tells the agent what it gets. It does not explicitly distinguish itself from sibling get_deal, so it falls short of a 5.

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?

There is no when-to-use or when-not-to-use guidance and no alternatives named, even though get_deal and compare_products appear to overlap on price data. The 'Is this a good price?' framing hints at a purchase-decision context but that is inference, not guidance.

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