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

Annotations already declare readOnlyHint and destructiveHint, and the description adds meaningful behavior: each call acknowledges the previous part, returns the next one, and the first part already counts as a delivered read. This goes beyond the structured annotations without contradicting them.

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?

Four compact sentences, front-loaded with purpose, followed by mechanics and usage criteria. Each sentence contributes; the optionality point is slightly repeated in the final warning, but the overall structure is tight and scannable.

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 two-parameter continuation tool with annotations and no output schema, the description explains the return behavior, acknowledgement semantics, and the decision context well. It could mention how the end of the read is signaled, but that is not essential for correct invocation.

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%, and both parameters already have descriptive text in the schema. The description reinforces that read_id and receipt must come from the preceding part, but it does not materially add new semantic information beyond that.

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 states a specific verb and resource: 'Fetch more of an Arroway read that did not fit in one response.' It clearly distinguishes continuation from the initial read and sibling tools by explaining that each call acknowledges the preceding part and returns the next one.

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?

It gives an explicit when-to-call condition: only when something in the first part's list of later contents bears on the task, and it warns not to call as a formality. It does not name alternative sibling tools, but the relevant alternative—not continuing—is directly addressed.

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