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

Annotations already declare readOnly, idempotent and closed-world behavior, so the bar is lower. The description adds useful context beyond them: the bounded 265-municipality domain, accepted identifier formats, and the fact that a link to the municipality page is returned — important given there is no output schema.

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?

A single dense sentence that front-loads the returned data and then the key formats. It is slightly crammed toward the end ('with the link to its page'), but no sentence is wasted.

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 one-parameter, read-only, no-output-schema tool this covers the essentials: what comes back, and how to identify the municipality. Remaining gaps — case sensitivity, partial matching, unknown-name behavior, and the slug option — are minor.

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 100%, so the baseline is 3, but the description goes further by giving concrete Bulgarian-script examples (Първомай, Столична), which is exactly the kind of hint an agent needs to format a Cyrillic `name` correctly. It does omit the slug option that the schema mentions, so it is not fully additive.

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?

The description names the exact resource (one of 265 municipalities) and the exact payload (population, births, deaths by year) plus the lookup key formats. It is clearly distinguishable from siblings like get_region_wages or get_dataset, which cover different resources.

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 implicit: an agent can infer this is the tool for municipality-level demographic data, but the description never states when to prefer it over a related sibling or what to do if the name is ambiguous or unknown. There are no alternatives or exclusions named.

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