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

Annotations already declare read-only, idempotent, non-destructive, closed-world behavior, but the description adds real substance on top: which condition tokens it parses (data GB, price ceiling, network, 5G, unlimited calls, free SIM, tethering, bundling, data sharing, no-conditions, carrier, lifetime/period/first-come), that data comes from carrier official pages, and that it also returns a 기간할인 comparison with post-discount price and 24-month total. Return format and result-count limits are still unspecified.

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 paragraph, front-loaded with the core purpose and then progressively adding parsing scope, return behavior, and examples. Dense but every clause earns its place; the parenthetical condition list is long yet informative rather than filler.

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?

There is no output schema, so the description carries the return-value burden, and it does describe the main payload (matching plans plus a 기간할인 comparison with total 24-month cost) and the id-to-fetch handoff. For a single-parameter NL search tool this is nearly complete, with only result shape/ordering left implicit.

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% and the single parameter is just labeled '한국어 검색어', so the schema alone conveys little. The description adds genuine meaning by showing that the parameter accepts free-form Korean natural language and by enumerating the condition patterns and example phrasings the parser understands.

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+resource: natural-language search over Korean MVNO (알뜰폰) plans, sourced from carrier official sites. It clearly distinguishes itself from fetch (which it says handles detail lookup), but does not differentiate itself at all from the sibling 'search_plans', leaving the agent to guess which search entry point to use.

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 explicit context for use (drop a plain Korean query in as-is) plus five concrete example queries covering carrier, data, price cap, 5G, unlimited-call and first-come-limited cases, and names fetch as the follow-up for details. It stops short of stating when NOT to use it or how it relates to search_plans.

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