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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds critical context beyond that: it explains the two possible result shapes, cites the source-URL inclusion for qualitative notes, and explicitly promises not to fabricate dollar amounts. This strongly informs agent expectations.

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 tightly written sentences with the core purpose first, followed by the behavior nuance and an important honesty constraint. No filler or redundancy; every sentence earns its place.

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 only three parameters, full schema descriptions, an output schema, and annotations covering safety, the description is nearly complete. It explains exactly what an agent should expect in both data-availability scenarios. A small gap is the lack of explicit routing guidance relative to sibling tools.

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 100%, so the input schema already documents all three parameters well. The description adds no unique parameter semantics beyond restating the general inputs, which matches the baseline of 3.

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 ('Estimate') with a clear resource ('permit fee') and scopes it to residential projects based on jurisdiction, project type, and valuation. It also differentiates itself from sibling tools by describing the dual output forms (numeric breakdown vs. qualitative feeNotes).

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 clearly implies when this tool is appropriate and explains output behavior, but it never explicitly names alternative sibling tools or states when to prefer this over check_permit_requirements or get_permit_rule_details. The use case must be inferred from the stated inputs and output.

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