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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds value by explaining exactly how each mode transforms the input, which is behavioral detail beyond the annotations. It also cites the source URL, adding provenance context.

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?

Three sentences with zero waste. The core behavior is front-loaded, each mode is defined in one clause, and the source URL is appended without disrupting readability.

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 simple two-parameter text transformation tool with full schema coverage and an output schema, the description is nearly complete. It could explicitly mention that the output is the transformed text, but the output schema likely covers that. The mode semantics are fully specified, which is the main contextual need.

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 schema already documents both parameters. The description adds value by explaining the semantic difference between 'words' and 'each' in plain language, which complements the schema's enum descriptions. The default behavior ('characters') is also clearly stated.

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 ('Reverse') and resource ('text'), and immediately distinguishes three modes ('characters', 'words', 'each') with precise behavioral definitions. This clearly differentiates it from sibling text tools like hopi_upside_down_text or hopi_text_repeater.

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 explains the three modes and their effects, giving an agent enough context to choose the right mode. It does not explicitly state when to use this tool over alternatives like hopi_upside_down_text, but the mode definitions make the usage context clear.

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