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

Adds significant behavioral context beyond annotations: 'Pure deterministic math — no advice, no loan-approval claim' and 'Always surface the disclaimer field.' Annotations already indicate readOnly/idempotent/non-destructive; description enriches with operational constraints.

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?

Three sentences, front-loaded with purpose, no unnecessary words. Each sentence earns its place: purpose, usage guidance, and output summary with disclaimer note.

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?

Despite 6 parameters and required outputs, the description covers all key aspects: what it compares, when to use, what it returns (including disclaimer). Output schema exists so return values are further detailed; description provides sufficient high-level completeness.

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%, so each parameter is described in the schema. Description does not add further parameter details but summarizes outputs. Baseline score of 3 applies as description adds no extra parameter meaning.

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?

Description clearly states it compares staying vs. transferring a home loan, lists what it returns, and explicitly says when to use it (user asks about switching/refinancing). Distinguishes from siblings like simulate_loan_prepayment.

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?

Provides explicit usage context: 'Use when the user asks...' and clarifies it is pure math with no advice/approval. Lacks explicit when-not-to-use or alternative tools, but context is sufficient.

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