x5_get_price_changes

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

Annotations already mark the tool as read-only and idempotent, so the description does not need to restate that. It adds behavioral nuance by noting the comparison is done separately by network and unit and that promotions may explain price differences, which helps set expectations about result interpretation.

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 definition consists of two short sentences with no filler. The core comparison logic is front-loaded, and the promotions caveat adds useful interpretive context without bloating the text.

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?

The description is adequate for the primary behavior but omits details an agent might need: there is no output schema, yet the response format (which PLUs, which prices, how the limit applies) is not described, and no sibling routing guidance is offered. Given the annotations cover safety, this is a moderate gap rather than a severe one.

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?

With zero schema description coverage, the description must carry parameter meaning, and it does for the core fields: 'period' maps to from/to and 'network' is explicitly referenced. However, limit and categoryCode receive no semantic explanation, though their names and schema constraints leave them partially inferable.

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 specifies a concrete action—comparing the first and last known price per PLU—and scopes it by period, network, and unit. This distinguishes it from sibling tools like x5_get_product_history or x5_search_purchases, which target individual product histories or purchase records rather than aggregate endpoint price comparisons.

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 implies a clear use case—analyzing price movement between period endpoints—but never states when to choose this tool over the listed siblings, nor any when-not conditions. An agent must infer the selection criteria from the stated behavior.

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