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

No annotations are present, so the description carries the full behavioral disclosure burden, and it does so thoroughly. It reveals the exact payment amount and recipient, the HTTP 402 on unpaid requests, the fact that a valid X-PAYMENT makes the same URL return JSON, and the chunking behavior for newest vs older content. These are non-obvious behaviors an agent needs to call this tool correctly.

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 dense and front-loaded with the endpoint and payment details, and every sentence carries information. However, it is packed into a telegraphic paragraph with inline prices and parentheticals, which makes it harder to scan than a more structured 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?

Despite having no output schema and no annotations, the description provides the critical context needed to invoke the tool: cost, payment flow, auth behavior, failure mode, and chunk pagination. It does not describe the JSON response shape or define 'chunk' precisely, which would be useful given the absence of an output schema, but the operational details are largely complete.

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 input schema has 100% description coverage and already documents id, page, before, and x_payment clearly, so the baseline is 3. The description adds pricing and the 'same door, not a new SKU' framing, and it reinforces the before/newest-chunk behavior, but it does not add substantial semantic meaning beyond the schema.

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 specifies a concrete paid GET endpoint and identifies the resource as 'EMA human-medicine referral procedure text,' with id-based and chunk-based retrieval. It is clearly not a tautology, but it never states the tool's purpose in a standalone sentence and relies on the path and payment details to convey meaning, so it stops short of full clarity.

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 operational guidance about whether to request the newest chunk or an older chunk via ?before, and about payment behavior, but it gives no guidance on when to choose ema-referrals over sibling tools such as get-page, get-one, search, or ticks. No alternatives or exclusions are mentioned, leaving tool-selection unclear.

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