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

With readOnlyHint=false and idempotentHint=false, the description adds meaningful behavioral context: Stripe shows the price, takes the card, and, for keepsake, collects the postal address. It also states 'This tool never takes a card and never names a price,' clarifying that the agent should not quote prices itself. No contradiction with 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 description is four sentences and every sentence earns its place: what it returns, what Stripe does, what the tool itself does not do, and where to get prices if asked. It is front-loaded with the core purpose and remains compact.

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 tool with no output schema, this is nearly complete: it specifies the returned artifact (payment link), the Stripe flow, the price-source external URL, and the only special behaviour around keepsake. It could add what happens on repeat calls or invalid handles, but that is a minor gap for this complexity.

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 baseline is 3. The schema already explains both 'book' (handle from start_book) and 'option' (voices, book, or keepsake). The description adds only the detail that keepsake is the printed hardcover, which is useful but not a major compensation burden.

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 names a specific verb ('Returns a payment link') and a specific resource ('one of the three ways to keep the book'), and it enumerates those options: voices, book, keepsake. This clearly distinguishes it from siblings like order_status or start_book: this tool produces a live payment link, not status or setup.

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 gives clear context: use it to hand the organiser a payment page after the option has been chosen. It also explicitly says the tool never names a price and directs the agent to read prices from https://choruskeepsake.com/llms.txt when cost is asked, which is useful when-to-use guidance. It does not explicitly enumerate alternatives, but the price instruction effectively rules out misuse.

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