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

Annotations cover safety, but the description adds genuinely non-structured behavior: the separate service-enablement requirement and the guarantee that a missing enablement throws a specific, actionable upstream error rather than a generic failure. That is exactly the kind of failure-mode disclosure an agent needs for error handling and is not derivable from the schema or annotations.

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?

The core purpose and return shape are front-loaded in the first clause, and the operational caveats follow. Dense but almost every sentence earns its place; the error-behavior sentence is slightly verbose but carries real value.

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-param read-only tool with no output schema, the description fully covers what is returned, what the ids mean downstream, the auth/enablement prerequisite, and the failure mode. Nothing an agent needs to call 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 coverage is 100%, so baseline is 3. The description adds meaning beyond the schema by clarifying that each returned mst is itself a historical version id passable to kr_law_article, and restates the BYOK contract for _apiKey. This goes slightly beyond the schema's own wording, warranting a 4.

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 resource (revision history for a South Korean statute) and enumerates exactly what it returns: promulgation date, promulgation number, entry-into-force date, each as a separate historical mst. It also names the sibling (kr_law_article) that consumes the output, so an agent can distinguish it from kr_law_search and kr_law_article without opening schemas.

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?

Implies the workflow clearly: use this to enumerate historical versions, then pass each returned mst to kr_law_article. It also states a hard prerequisite (OC must have 법령연혁 enabled under My Applications). It stops short of an explicit 'do not use this for X, use kr_law_search instead' exclusion, so not a 5.

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