regex

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

With no annotations, the description carries the burden of behavioral disclosure. It adds useful context about the required regex format (slashes and flags), but it does not disclose the return value (e.g., boolean true/false), behavior on non-matching strings, or whether validation is full-string or partial. This leaves important behavioral aspects unspecified.

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 two sentences, front-loaded with the primary purpose and followed by a necessary usage detail. Every sentence earns its place; there is no redundancy or filler.

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, but with no output schema and no annotations, the description must explain the return value and input expectations. It states purpose and regex format, but omits what the tool returns and how the target string is provided. This makes the description adequate but not fully complete for an agent to confidently invoke the tool without additional assumptions.

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?

The input schema has no parameters, so the baseline for this dimension is 4. The description adds meaningful context by explaining how the regex pattern must be formatted (leading/trailing slash and flags), which is not evident from the empty schema. However, it does not clarify how the String being validated is supplied, leaving a small gap.

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 the tool's function: 'Validates that a String against a supplied RegEx pattern.' This specifies the action (validates) and resource (String against RegEx pattern), and it is distinct from sibling tools like regexreplace, which performs replacement rather than validation.

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 gives clear usage context: use this tool when you need to check if a string matches a regex pattern. It also provides an explicit operational guideline ('Include the leading and trailing '/' in your RegEx pattern and optionally append flags') that helps the agent invoke the tool correctly. However, it does not explicitly mention when not to use it or name alternative tools for related tasks.

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