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

Annotations already establish readOnly/idempotent/non-destructive, and the description adds meaningful behavioral context: it does not move money, the trader signs in their own wallet, renewal is every 30 days, and the wallet authorization is per-wallet. It still omits what the response looks like and any rate/availability caveats beyond the 'when live' 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?

Content is front-loaded (plans and pricing first, then payment mechanics, then the safety note) with no filler sentences. It is a single dense sentence that is slightly hard to parse due to em-dash interjections, but every clause carries information.

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 output schema, the description carries the return burden and does describe the content returned (pricing, inclusions, treasury, token, transactions). Both parameters are optional read-only inputs with full schema coverage, so little else is needed; only the concrete response shape is left implicit.

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 the schema already documents both the plan enum and the wallet address. The description mirrors this (plan pricing, wallet needed for the renewing subscription authorized for that wallet only) without adding format or usage detail beyond the schema, so 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?

The description clearly identifies the resource returned (plan pricing per 30 days, inclusions, treasury/token, and the approve/subscribe steps), so an agent understands what it will get. It is less explicit about the verb (read vs prepare) and does not distinguish itself from siblings like plan_claim, catalogue, or vault_prepare.

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 implied (pick a plan and wallet to obtain payment steps, when the subscription vault is live) but there is no explicit 'use this when / not when' guidance and no named alternative among siblings. An agent must infer when to call plans versus plan_claim or vault_prepare.

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