Dict Metro City

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

With no annotations supplied, the description carries the full burden, and it does disclose the payload content (metro lines and stations). It is silent on behavior an agent would want: whether cities without a metro return empty or error, what happens with an invalid id, and whether authentication is required.

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?

One compact sentence that front-loads the verb and resource and spends its words on the example, which is genuinely useful. Nothing is padded, though the example parenthetical slightly outshines the missing routing guidance.

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 simple single-parameter dictionary lookup this is close to adequate, but with no output schema and no annotations the description should say more about the shape of the response (flat line list with nested stations?) and edge cases. It leaves the agent to discover the identifier-source and empty-result behavior at call time.

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 coverage is 0% — the single parameter is just a bare string — so the description must compensate, and it partly does by giving an example value ('4 = Moscow') and identifying the expected id domain. However, the area-id versus city-id mismatch is left unresolved, so the agent cannot be fully certain which dictionary the identifier comes from.

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 ('Get') and a specific resource ('metro lines and stations of a single city'), so an agent knows exactly what it returns. It does not differentiate itself from the sibling 'dict_metro', which likely serves a related lookup, and the name says 'city_id' while the description says 'area id', leaving a small ambiguity about which identifier is expected.

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?

Usage is only implied: 'of a single city by area id' suggests using this when the city is already known (e.g., after resolving via dict_areas), but the description never says when to prefer it over dict_metro or dict_areas. No exclusions, prerequisites, or alternatives are named.

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