validation_matches_regex

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

No annotations are provided, so the description carries the full burden and leaves important traits undisclosed: 'matches' is ambiguous between full-string match and substring search, and nothing is said about case sensitivity, regex flavor/dialect, or flags. For a tool whose result hinges on exactly those semantics, this is a meaningful gap.

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?

A single well-formed sentence with the key concept front-loaded and zero filler. Nothing could be cut without losing meaning.

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?

An output schema exists, so return-value explanation is not required. However, for a regex tool the match semantics (full vs partial, flavor, flags) are essential to call it correctly, and the description is silent on all of them.

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 0%, and the description implicitly maps its two concepts ('a string' -> text, 'a regular expression pattern' -> pattern), which is slightly more than the bare schema titles. It adds no syntax, flags, or anchoring details, so it only partially compensates for the uncovered parameters.

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?

States a specific verb ('Check whether') and resource ('a string' against 'a regular expression pattern'), so an agent can tell exactly what it does. It does not, however, distinguish itself from the many neighboring validation_* tools (is_email, is_uuid, is_ipv4), which a generic regex matcher overlaps with conceptually.

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?

There is no when-to-use guidance, no exclusions, and no mention of alternatives. An agent must infer from the name alone whether to prefer this over a dedicated validator such as validation_is_email. Pure 'what', no 'when'.

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