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

With no annotations, the description carries the full burden and does an excellent job. It discloses the weekly update cycle, the exclusion of unconfirmed specials before the Wednesday changeover, and the possibility of an empty list afterward. This goes beyond a simple 'retrieve specials' statement and provides meaningful behavioral context.

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 three sentences, front-loaded with purpose, and every sentence contributes—purpose/filters, update frequency/savings, and a critical exclusion rule with an alternative. There is no waste or redundant repetition of schema details.

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?

For a list tool with optional parameters and no output schema, the description covers essential aspects: what it returns (specials with savings), filtering options, update cadence, and an important edge case. It could be more detailed about the exact result structure, but for this simple tool it is sufficiently complete.

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 67%, with limit and category already described in the schema. The description adds context that 'Filter by retailer or category' and that 'Results include savings amounts', which clarifies the meaning of the retailer and category filters. It also connects the retailer filter to the catalogue changeover behavior, enhancing semantic understanding without repeating schema details.

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 clearly states 'Get current grocery specials and promotions' with a specific verb and resource, and it distinguishes itself from sibling tools like get_product by focusing on specials/promotions rather than individual product data. This makes the tool's purpose immediately obvious.

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 explains when to use this tool for current specials and provides an explicit alternative: 'Individual products still expose such prices via get_product with special_may_have_ended: true'. It also warns about the near-empty list after a catalogue changeover, which is a valuable usage caveat.

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