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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: the answer is re-derived rather than cached, meaning the original tool is re-executed and the window is stable relative to the original truncation. It does not mention cost or latency of re-derivation, which would have completed the picture.

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?

Two compact sentences with no filler, and the identifying detail (the truncated answer, its tool, arguments and named field) is front-loaded. The trailing clause 'so the window is the one that was cut' is the weakest part and reads slightly redundantly, but no sentence is wasted.

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 5-parameter utility with a nested arguments object and no output schema, the definition explains the mechanism but not the result: whether the response signals remaining data, truncates again at the budget, or errors on an out-of-range offset is left implicit. The re-derivation note carries the important behavioral load, but return-side behavior is a gap.

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 60%, with 'tool', 'field', and 'arguments' documented in the schema itself. The description goes beyond that by tying 'arguments' to the original call and by glossing limit/offset as 'which items or characters to return', clarifying that the unit of the window depends on the field type. This compensates reasonably for the undescribed limit/offset parameters.

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: read one window of an answer that was truncated by the size budget. It also binds the tool to a prior call's notice (tool, arguments, named field), which makes it distinguishable from ordinary read tools in the sibling list. The phrasing 'the window is the one that was cut' is slightly cryptic, but the core purpose is unambiguous.

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 rather than stated: you use this when an answer 'came back cut to the size budget' and its notice named a field. There is no explicit when/when-not guidance, no note on what to do if the original call is no longer reproducible, and no alternatives named. An agent can infer the trigger but must reconstruct it from the prose.

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