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 meaningful context: the high-cost percentage rules (270% standard, 315% for High Cost Areas, 405% for AK/HI/GU/VI) and the caveat that ROAD to Housing Act base amounts are enacted but pending implementation. This goes beyond annotations without contradiction.

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 two sentences, front-loaded with the core computation and then a caveat. It is efficient with no wasted words, though the first sentence is dense and could be split for readability.

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 should clarify return values, but it only says it 'reports' the ROAD base amounts without specifying format or structure. It also omits any program-specific behavior. Given the moderate complexity of the calculation and the low schema coverage, the definition is adequate but has clear gaps.

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 25% (only unit_mix is described). The description partially compensates by explaining that elevator affects table amount and that high_cost_pct is a percentage multiplier with specific standard values. However, it completely ignores the 'program' parameter (enum with six options and default 223f) and does not clarify defaults or constraints, leaving most parameters undocumented.

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 uses a specific verb ('Compute') and resource ('CY2026 statutory mortgage limit for a unit mix'), making the tool's purpose clear. However, it does not explicitly distinguish this tool from sibling tools like size_223f or program_facts, so it falls short of the highest bar for sibling differentiation.

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 what the tool does but provides no explicit guidance on when to use it versus alternatives. There is no mention of prerequisites, exclusions, or which sibling tool to choose for related tasks, leaving usage entirely implied.

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