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

Annotations already cover the safety profile (readOnly, idempotent, open-world, non-destructive), yet the description adds substantial context beyond them: data vintage (2025-12-31, release D25_29sep2026), per-block counting semantics, the H3-cell fallback when a point is in no FCC block, satellite listed last, and the crucial caveat that speeds are advertised maximums, not measured. This is unusually rich behavioral disclosure.

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?

Dense but front-loaded: the core identity, data source, and counting model come first, then secondary ordering and caveats, then input formats. Nearly every clause carries information, though the single-block prose could be broken into shorter sentences for faster scanning.

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 carries the return-shape burden and does so: providers, technologies, download/upload tiers in Mbps, residential vs business-only location counts, and the wired/fixed-wireless-before-satellite ordering. Input modes and data limitations are both covered, leaving nothing an agent needs missing.

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 baseline is 3. The description adds meaning beyond the schema by explaining that the address parameter is geocoded via the US Census geocoder and that coordinates must be US-based, though it does not state precedence if both address and lat/lon are supplied.

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 and resource: fixed broadband availability for a US location from the FCC Broadband Data Collection, counted per 2020 Census block. The resource is unambiguous enough that an agent can distinguish it from drinking_water, environment_near, and location_scores without opening any schema.

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?

Gives clear applicability context (US locations only, accept either a geocoded street address or lat/lon) and an important limitation ('cannot confirm service at one house'). It never names an alternative tool or states when a sibling should be preferred, so it stops short of full routing guidance.

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