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

Annotations already declare readOnlyHint=true and openWorldHint=false. The description does add real behavioral context beyond that: the data is generated from config.PLANS, is live rather than hand-maintained, and includes the founder/founding-seat block that other surfaces offer. That context is useful, but it arrives wrapped in historical narrative rather than stated as a guarantee about freshness or scope.

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?

Only the first sentence is front-loaded with what the tool returns; the remaining two paragraphs are an internal post-mortem about past drift and historical pricing mistakes. That backstory, while motivating, does not help an agent decide to call or not call the tool and consumes most of the description.

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 values need not be explained, and the read-only annotation covers safety. What is missing is any operational framing (e.g., that this is the authoritative answer for cost questions and that no freshness check is needed), which the description gestures at only indirectly.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly describes no arguments, only output content.

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 opening sentence names a specific resource (pricing tiers, features, monthly fact-check quotas) that an agent can match to a cost question. It does not, however, distinguish itself from adjacent siblings such as get_skarvia_info or get_guide, so the boundary is left to inference.

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?

Usage is only implied, via the closing anecdote that an agent asked what Storskarvia costs should not answer from stale prose. There is no explicit 'use this when X, otherwise use Y' and no sibling is named as an alternative for general company questions.

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