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

Annotations already cover the read-only/open-world profile, and the description adds genuinely new operational facts beyond them: cost ($0.01 USDC per call via x402 on Base) and the incomplete-verification behavior for unsourced numbers. It omits auth requirements or rate limits, keeping it from a 5.

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?

Core capability is front-loaded in the first clause, with verification semantics before the pricing tail. It is a single dense run-on sentence, but each clause (number classes, output markers, sources, unverified rule, price) carries information 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?

With no output schema, the description usefully covers the return shape (MATCH/MISMATCH plus date and source). However, for a 4-parameter tool with zero schema documentation, the unexplained corp/year/as_of inputs are a real gap an agent cannot resolve from this text alone.

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 0% and the description never explains the non-obvious parameters corp, year, or as_of, nor how they interact with text. Only the implicit notion of a date is hinted at via 'with date and source,' which is not enough to guide an agent supplying these inputs.

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 ('Fact-check numbers in Korean finance text') and enumerates exactly which number classes are checked (rates, KTB yields, FX, listed-company revenue/profit, % vs %p, 조/억/만 units). This clearly separates it from sibling lookup tools like kr_rates_query or kr_fx_rate, which fetch values rather than verify prose.

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 clear context for use: Korean finance text containing checkable numbers, and states the terminal behavior for unsourced numbers ('stay unverified'). It does not name an alternative sibling (e.g., kr_rates_query) or state a when-not-to-use condition, so it falls 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.