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

With no annotations, the description carries the full burden of behavioral disclosure. It explicitly states payment requirements ($0.05), that unpaid requests return HTTP 402, and that a valid X-PAYMENT header makes the same URL return JSON. It also clarifies pricing differences and that this is not a new SKU, which is rich behavioral context for an agent.

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 but efficient: it packs URL, cost, payment address, operation modes, error behavior, and response format into a short paragraph. Every sentence contributes information. The opening sentence is slightly cluttered with the payment address, but overall it is a well-structured, appropriately sized 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?

Given no output schema, the description does state that the response is JSON, which covers the return format at a high level. It also covers payment, error handling, and parameter selection. It does not describe the JSON structure, but for tool selection and invocation this is likely sufficient. The lack of output schema raises the bar slightly, but the description and schema together cover most practical needs.

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 description adds meaningful semantic value beyond the schema by attaching costs to each parameter mode, clarifying that id is a different pricing tier, and that page is ignored when since/before is set. This is useful supplemental information, though the schema already covers most parameter meaning.

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 identifies a specific resource (FDA CDER Integrated Review text) and the operation is GET, with an explicit URL. It clearly explains the different retrieval modes (by id, newest chunk, older chunk, watermark), though it does not explicitly name a sibling tool to distinguish from. This is clear but not quite at the level of explicitly differentiating itself from siblings.

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 concrete guidance on which parameter/variant to use: plain GET for the newest chunk, ?before for an older chunk, ?since for texts newer than a watermark, and ?id for one official text. It provides clear context but does not discuss when to choose this tool over a sibling, only within-tool usage.

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