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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral information — that the payload is trimmed to summary and URL unless full text is enabled — but never says how full text is enabled, leaving the agent unable to act on that condition.

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?

Two sentences, zero filler. The primary behavior and the addressing modes come first, and the payload caveat follows, which is the right ordering for an agent scanning the definition.

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?

An output schema exists, so return structure need not be explained, and the description is adequate for a simple single-record getter. The gaps are the dangling 'full text is enabled' condition with no way to trigger it and the unaddressed case where all optional parameters are omitted.

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 explains that url is an alternative to verticalSlug+slug and that slug and verticalSlug are required together. The description restates the same either/or addressing scheme without adding format, precedence, or error-behavior detail. Baseline 3 applies.

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 and resource: 'Returns one Insights article', with the lookup keys named. The singular 'one' implicitly distinguishes it from list_insights and search_insights, but it never names those siblings explicitly, so the differentiation is inferred rather than stated.

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 description presents the two addressing modes (vertical+slug or canonical URL), which is useful usage context. However, it gives no guidance on when to prefer this over list_insights or search_insights, and says nothing about what happens when no parameters are supplied even though all three are optional.

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