Compare mortgage products

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

No annotations are present, so the description carries the full burden. It states that the tool does not recommend a product, which is useful, but it does not disclose what exactly happens during comparison (e.g., returns a list of products with rates, or side-by-side metrics). It also doesn't mention any side effects or requirements, so the agent has limited understanding of the tool's behavior beyond the schema.

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 a single sentence that is direct and front-loads the purpose and key qualifier. There is no fluff, and it conveys the essential information efficiently.

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?

Given moderate complexity (5 parameters, no annotations, no schema descriptions), the description is minimal. It explains what it does (compare) and its stance (no recommendation), but it lacks details about expected output structure, how to handle results, any assumptions about input formats, or whether it fetches live rates. With an output schema present, return format may be covered, but the description still doesn't fully equip an agent to call it correctly for all scenarios, especially when to use it vs. alternatives.

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 0% schema description coverage, the description must compensate for parameter meaning, but it does not. The description mentions 'equal inputs' but does not explain the parameters like principal_eur, term_years, fixed_rate_years, start_date, or rate_date. However, many parameter names are self-explanatory, and the output schema exists, which may clarify the output. Since the schema provides no property descriptions, the description's lack of parameter detail is a gap, but the names help.

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 the tool's purpose: comparing products with equal inputs and explicitly says it does not recommend one. This is a specific verb ('compare'), resource ('mortgage products'), and a key qualifier ('without recommending'). It distinguishes itself from single-product calculation tools, though it does not name the sibling tool for that, but the context is clear.

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 gives a clear condition for use: 'using equal inputs' and 'without recommending one,' which implies it is for objective comparison. However, it does not explicitly state when NOT to use this tool versus alternatives like 'calculate_mortgage' or 'list_mortgage_products.' It provides some usage context but lacks explicit exclusions or alternative routing.

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