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

With no annotations, the description carries the full burden. It does disclose a genuine behavioral trait — results come live from the database rather than a cached list — and implies a read-only operation via 'Returns'. However, it never covers auth requirements, result ordering, or what the returned city objects look like beyond containing a slug, leaving real gaps for a no-annotation tool.

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, no filler, and the core purpose is front-loaded ahead of the sequencing guidance. The parenthetical platform clarification is the only expansion and is brief.

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 zero-param enumeration with no output schema and no annotations, the description covers what the tool does, when to call it, and how to use its result. The remaining gap is the return shape (whether entries carry name plus slug, and ordering), which matters slightly more because no output schema exists.

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?

Zero parameters, so the baseline is 4. The description goes slightly beyond by explaining the semantic payload the caller needs downstream (the city slug), which is more than the empty schema can convey.

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 ('Returns the cities ... currently serves') plus the data source ('live from the database'), so an agent knows this is a dynamic enumeration, not a static list. It is clearly distinguishable from siblings like city_stats (metrics) or search_programs (search), which the description explicitly forwards to.

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 an explicit trigger ('Call this first when the user's city matters') and the downstream action ('then pass the city slug to the search tools'), effectively naming the alternatives it feeds. An agent knows both ordering and what to do with the output without opening another schema.

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