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

Annotations already establish readOnly, idempotent, closed-world, non-destructive, so the safety profile is covered. The description adds genuinely useful domain context beyond that: limits are 'a hard cap, no overage or per transaction fees', which affects how an agent should present the plans. It doesn't say whether pricing is live or cached, keeping it at 4.

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?

A single tight sentence that front-loads what is returned and only then states the usage condition. Every clause carries information: the field list, the hard-cap caveat, and the sequencing hint. Nothing is wasted.

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 parameters and no output schema, the description carries the burden of explaining the return shape, and it does so by enumerating the returned fields. Minor gaps remain — currency of the prices, ordering of tiers, and whether prices are current — which matter when recommending a plan.

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 the schema-baseline is 4 and there is nothing for the description to clarify on inputs. The description correctly spends no words on parameters and instead characterizes the payload.

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 (List) and resource (GriffNode's plans and pricing) and then enumerates exactly what each entry contains: tiers, monthly/yearly price, monthly transaction limits, features. An agent can immediately distinguish this from get_prices, list_currencies, or upgrade_plan in the sibling set.

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?

Explicitly says when to use it — 'show the user their options (and what an upgrade unlocks) before recommending one' — and names the follow-up tool create_upgrade_checkout, which sequences it against the upgrade flow. No explicit when-not or disambiguation against sibling get_prices is offered, 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.