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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds valuable non-structured context: Italy-only coverage, a limited catalogue of ~200 Italian-named staples, and the MCP Apps card rendering. It does not mention rate limits or caching, but the annotation burden is largely met.

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 the when-to-use triggers and examples, then covers scope, alternative, and output. It is somewhat long and the parenthetical product list is close to redundant with the schema examples, but every sentence carries information.

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?

An output schema exists so return values need not be explained, yet the description still summarizes them (median/lowest, weekly and per-chain, link). Combined with the Italy-only and catalogue-size limits and the sibling routing, an agent has everything needed to call it 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 single param is documented in the schema, so baseline is 3. The description goes beyond it by clarifying the expected vocabulary is a fixed set of ~200 staple products named in Italian (with examples like detersivo, pannolini), which meaningfully constrains how to fill the parameter.

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 (weekly price trend of a product) with verb-like intent and explicitly scopes it: median/lowest flyer prices per week and per chain. It also distinguishes itself from the sibling search_flyer_offers, which handles specific brands and models.

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?

Gives concrete trigger conditions ('how much does pasta cost this week', 'is coffee more expensive than last week') and names the alternative tool with the condition that selects it. Nothing is left to inference.

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