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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: the coverage limitation that Georgian Post assigns street-level codes only in the three largest cities, plus the source of the data. It does not mention rate limits or result-ordering behavior.

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?

Four sentences, front-loaded with the core purpose and input scope, then the important coverage caveat. The closing attribution ("Data from the web page of Georgian Post") is mildly redundant with the first sentence's mention of Georgian Post, but costs little.

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 three-parameter lookup tool with an output schema and full annotation coverage, this covers purpose, inputs, languages, geographic caveats, and source. Minor omissions are the limit behavior and what happens when nothing matches, but nothing essential to calling it correctly is missing.

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 query, limit, and language. The description reinforces the accepted input types and the Georgian/English option, which maps loosely to the language parameter, but says nothing about limit or the 3-100 character constraint. Baseline 3 is appropriate.

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 states a specific verb and resource ("Finds the postal codes of Georgian Post") and scopes it to Georgia with accepted input types (address, street, town, village) and languages. It also states the return shape (matching address, 4-digit postal code, district), so the tool is fully identifiable and cannot be confused with any sibling, all of which serve unrelated domains.

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?

It gives actionable usage rules: use street-level lookup in Tbilisi, Batumi, and Kutaisi, and "For another town or a village, search its name" elsewhere. There are no alternative postal tools to route to, and no explicit exclusions or failure cases are stated, so it falls just short of a 5.

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