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

Annotations provide readOnlyHint=true and idempotentHint=true covering the safety profile. The description adds the payment/pricing detail ($2.00 USDC via x402), which is a behavioral trait not visible in annotations and critical for the agent to know. It also discloses the 'decision-ready verdict with cited public records' nature of the output. No contradiction with annotations.

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?

Two sentences, front-loaded with purpose, and the payment info is compactly stated. Every sentence earns its place. Slight inefficiency: the payment detail could arguably be split but is already concise.

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 paid API tool with full schema coverage and read-only/idempotent annotations, the description captures the essence: it's a comprehensive, paid permit-intelligence verdict service covering specific cities. The payment model is disclosed, which is the main non-obvious aspect. Could add what the verdict format looks like, but given readOnlyHint and no output schema, the coverage is reasonably 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 100%, so all three parameters have descriptions in the schema itself. The description adds the payment-header flow context ('Omit on first call to receive payment requirements' is in schema too). The description's main added value is the overall commerce model, not per-parameter detail. Baseline 3 is appropriate given full schema coverage.

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 provides 'address-level building-permit intelligence' with normalized history, activity signals, and a decision-ready verdict with cited public records. It clearly differentiates from siblings (find_active_projects, check_permit_activity) by being the comprehensive 'verdict' tool. Loses a point for not explicitly naming which sibling to use instead for lighter queries.

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 paid x402 payment flow is clearly disclosed ('Paid: $2.00 in USDC'), which is important usage guidance. However, it doesn't explicitly say when to use this vs check_permit_activity or find_active_projects. The 'first call to receive payment requirements' hint in payment_header param helps but the usage boundary between siblings is implicit, not stated.

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