Get to know my city

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

Even though annotations declare readOnly, idempotent, and non-destructive, the description goes well beyond them: it discloses the cache side effect, the slow first-call behavior, expected wait time, radius cap, and the confirm flow. No contradiction with annotations exists because the cache write is internal and idempotent.

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?

The description is dense and front-loaded: purpose first, then scope, then operational constraints. There is slight redundancy in the confirm instructions ('Omit confirm unless...' repeats the prior condition), but every other 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?

The description is comprehensive about cache behavior, routing limitations, and confirmation protocol. However, it omits the location parameter contract (city vs lat/lon, requiredness, precedence), which is a meaningful gap for a 5-parameter tool with no schema descriptions. The output schema mitigates the need to document return values.

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?

With 0% schema description coverage, the description explains radius_m (default 8000, cap 25 km) and confirm (only after user agrees) well. However, it never explains lat/lon/city semantics, whether one is required, or how they interact, leaving key location inputs to inference from their names.

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 opens with 'Pre-cache a city' and precisely states what is copied into cache (places and transportation tiles) and what is not (routing graph, buildings). This makes the tool's purpose unambiguous and clearly distinguishes it from query tools like find_places or route.

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?

Provides concrete usage context: call it before place searches so later queries read locally, and note that it will not speed up routing or building queries. It also says an already-cached city never needs another call. It does not explicitly name sibling tools as alternatives, but the guidance is clear enough.

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