Geocode

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

Annotations already cover readOnly/openWorld/idempotent/destructive, so the bar is lower; the description adds genuinely new context — the default provider (Nominatim) and a 1 request/second rate limit — which an agent needs to avoid throttling.

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 tightly written sentences with no filler; the mode and provider are front-loaded and the rate limit is appended where it belongs.

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 read-only geocoding tool with full schema coverage, the definition covers modes, provider, rate limit, and even the return shape (lat, lng, display name) despite no output schema. Only minor gaps, such as error behavior on ambiguous addresses, remain.

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 schema already documents each parameter's format, bounds, and forward/reverse applicability. The description adds nothing beyond what the schema states, so the 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 specific verbs (forward-geocode / reverse-geocode) and the resource (address or lat/lng), and names the provider. Sibling tools (distance_matrix, optimize_route, cluster_points) are clearly different tasks, so no confusion arises.

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 plus schema makes the mode-selection rule explicit: pass address for forward, lat/lng for reverse. It notes the rate limit, which is operationally relevant, but gives no explicit when-not-to-use or alternative-tool guidance.

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