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

Annotations already cover safety (readOnly, idempotent, non-destructive, open-world), and the description adds genuinely non-schema context: public-domain sourcing, a per-call price of $0.01 USDC via x402 on Solana, and an equivalent HTTPS GET endpoint. What it does not disclose is failure behavior — unmatched addresses, partial matches, or ambiguity resolution — which matters for an open-world geocoder.

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?

Front-loaded with the operation and input, then the return payload, then practical notes on licensing, price, and the HTTPS mirror. The long geography enumeration is dense but each item is load-bearing information the agent needs to judge fitness for a district or data-join task.

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?

No output schema exists, so the description correctly carries the return-value burden by listing the geography fields. Combined with price, endpoint, and licensing, an agent has enough to decide and call it. The remaining gap is response shape for failures or ambiguous addresses.

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 three parameters are already documented at the field level, including the address-vs-lat/lon alternative. The description restates the two input modes and that the address needs a house number, but adds no format guidance (e.g. ZIP, state abbreviation, suite handling) or tie-breaking rule when both modes are supplied. Baseline 3 applies.

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?

States a specific verb+resource ('US Census Bureau geocoder') and enumerates exactly what comes back: matched address, coordinates, FIPS state/county, tract, block group/block GEOID, place, congressional and legislative districts, ZCTA, CBSA, urban area. That is far beyond a restated title. It does not, however, distinguish itself from the sibling 'geocode' tool, which is the most likely confusion point for an agent choosing between them.

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?

It names use cases ('district lookups, data joins and address normalisation'), which implies when to reach for it, but gives no explicit when-not guidance and never mentions the sibling 'geocode' alternative. It also omits the key calling constraint that neither address nor lat/lon is required, so the agent must supply one of the two input modes on its own.

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