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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavioral context: the universe is restricted to KRX on-exchange corporate bonds that are senior and option-free, values are medians of recent executed yields (not quotes), and spreads are computed against both treasuries and the same rating in basis points. No latency, rate-limit, or empty-result behavior is disclosed.

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?

Content is front-loaded into a single dense block that leads with the resource and then the data dimensions, with zero filler sentences. The bracketed MCP branding prefix and the very packed phrasing make it slightly harder to scan, but nothing present is redundant.

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 two-optional-parameter tool with no output schema returning a rating × maturity matrix, the description does substantial work by specifying the bucketing, the spread basis, and the units. Missing are edge behaviors such as what happens when an issuer has no eligible on-exchange trades or when a rating/maturity bucket is empty, which matters for a market-data tool with sparse coverage.

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 both parameters and the baseline is 3. The description does add meaning for `stock` by explaining that supplying it returns that issuer's spread versus treasuries and versus its own rating in bp, but it never mentions the `kind` parameter's 금융채 (financial bond) branch at all, leaving that enum value's effect undefined in prose.

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 a specific resource (corporate/treasury yield curves) and enumerates exactly what is produced: treasury benchmark rates at 2/3/5/10/20/30 years with 1-month and 1-year comparisons, KRX on-exchange senior unsecured corporate yields by rating (AAA/AA/A/BBB) × remaining-maturity median, and spreads versus treasuries. The two operating modes (curve lookup vs. per-stock spread in bp) are stated explicitly, so an agent can distinguish this from the generic `bond`/`bonds` siblings without opening the schema.

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?

The closing sentence provides concrete example phrasings ('국고채 3년 금리', '지금 AA 3년 회사채 금리', '신용 스프레드', '이 회사 채권 스프레드'), which effectively tell the agent when this tool is the right one. There are no explicit exclusions or pointers to alternative sibling tools, and nothing says what to do if the user asks about a bond not covered by KRX on-exchange trading.

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