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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so safety is established. The description adds behavioral context by summarizing the three modes and their effects, going slightly beyond the schema by framing them in a single concise sentence. It does not cover edge cases like Unicode whitespace or newline handling, but that's acceptable given the 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 a single sentence with an efficient colon-separated list of modes. It front-loads the purpose and contains zero redundant words, making it highly concise and well-structured.

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?

The tool is simple (2 params, one enum), the schema fully documents parameters and defaults, and the output schema is present. The description covers the core behavior and modes, so there are no significant gaps for an agent to select and invoke the tool correctly.

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%: both `text` and `mode` have detailed descriptions, including the enum values and the default. The description largely repeats the mode semantics already in the schema, providing no new parameter meaning. This matches the baseline expected for high schema coverage.

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 opens with a specific verb and resource ('Remove or collapse whitespace in text') and then details three distinct modes. This makes it clear what the tool does and easily distinguishes it from sibling text tools like case-converter or reverse-text.

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 implicitly communicates when to use this tool—whenever whitespace needs to be removed or collapsed—and the mode breakdown provides clear context for each operation. However, it does not explicitly name alternatives or exclusion criteria, so it stops short of a 5.

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