text_invisible_scan

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

Without annotations, the description carries the full burden. It mentions the output (positions, names, categories) but does not disclose whether the tool is read-only, any potential side effects, or performance characteristics. It is adequate but could add that it is a safe scanning operation.

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 concise sentences with no redundant words. Front-loaded with the primary action and followed by a clear explanation of what it checks and reports.

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 one-parameter tool with no output schema, the description is fairly complete. It covers the what, how, and what is reported. Minor improvement could mention that it is a read-only operation, but overall sufficient.

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% with 'text' parameter described. The description adds meaning by specifying the scope (ALL invisible Unicode characters) and the output details (positions, names, categories), enhancing understanding beyond the schema.

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 clearly states that the tool scans text for ALL invisible Unicode characters, checking against a full database and reporting positions, names, and categories. This specific verb+resource scope distinguishes it from siblings like text_whitespace_detect or text_zwc_detect.

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?

No guidance on when to use this tool versus alternatives. For example, it does not mention that for specific invisible character types like whitespace or zero-width characters, there are dedicated sibling tools available.

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