regex_tool

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

No annotations are provided, so the description carries the behavioral disclosure burden. It explains what each action returns (test: match status, extract: matches and capture groups, replace: replaced text), which goes beyond the schema. It does not cover edge cases like invalid regex, but the core behavior is transparent.

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, front-loaded sentence that efficiently communicates the tool's purpose and action-specific behavior without redundancy. Every word contributes to understanding.

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?

Given no output schema and no annotations, the description provides a sufficient overview of the tool's functionality, including return values for each action. It does not explain every parameter in detail, but the core usage is well-covered for an agent to invoke 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 only 40%, and the description compensates partially by explaining the action parameter's values and the replacement parameter's $1 syntax. However, pattern, text, and flags lack semantic explanation beyond the schema, leaving some gaps.

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 performs regex test/extract/replace operations, with specific action values and their return behavior. It distinguishes from siblings like regex_generate (generation vs. testing/extraction) and text_replace (plain vs. regex replacement).

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 implies usage context by listing the three action modes, making clear when to use the tool for regex matching/extraction/replacement. It does not mention alternatives or exclusions, so it falls short of a 5, but the context is clear.

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