regex_extract

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

With no annotations, description discloses support for capture groups, named groups, multiline, and return format. However, it misleadingly says 'all matches' without mentioning the maxMatches limit (default 100, max 500), which is a behavioral detail.

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?

Four sentences, front-loaded with purpose, no redundant content. Efficiently covers purpose, capabilities, return format, and use cases.

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?

With no output schema, description explains return structure well. Missing edge cases like no matches (returns empty array) and the maxMatches cap, but otherwise complete for a regex extraction tool.

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?

All parameters have schema descriptions (100% coverage), so baseline is 3. The description does not add specific parameter-level meaning beyond what the schema provides.

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 runs a regex against text and returns all matches. It gives specific use cases like extracting emails and URLs, distinguishing it from sibling tools like csv_query or json_query.

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?

Provides clear guidance on when to use (extracting structured data from unstructured text) but does not explicitly mention when not to use or compare with alternatives like text_stats or html_to_markdown.

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