Tests input against pattern (Go's regexp package: RE2 syntax, not PCRE — no backreferences or lookaround; use inline flags like (?i) for case-insensitive matching). Returns the full match and captured groups.
| Name | Required | Description | Default |
|---|---|---|---|
| input | Yes | ||
| pattern | Yes | RE2 syntax |
| Name | Required | Description | Default |
|---|---|---|---|
| match | No | ||
| groups | No | ||
| matches | Yes |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description transparently discloses the RE2 syntax constraints (no backreferences/lookaround) and the return behavior (full match and captured groups). It does not mention edge cases like no-match behavior, but covers key aspects.
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 well-structured sentence that front-loads the purpose and adds parenthetical syntax details without waste. Every word adds value.
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 the tool's simplicity, the description covers the purpose, parameter roles, syntax rules, and return value. The existence of an output schema means return-value details don't need full explanation, so this is 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?
The schema only describes 'pattern' as 'RE2 syntax', leaving 'input' undocumented. The description clarifies both: input is the string to test, pattern is the regex, and adds detail about RE2 limitations and flags 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 the tool tests input against a pattern and returns the full match and captured groups. It distinguishes itself from sibling validators (email_validate, url_validate, jsonschema_validate) by being the general regex matching tool.
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 for regex matching, with context about Go's RE2 syntax and inline flags. It does not explicitly say when not to use it or compare with alternatives, but the regex-specific details make the use case clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Each tool targets a distinct validation domain: email, URL, regex, and JSON schema. There is no overlap; an agent can clearly distinguish which tool to use for a given validation task.
All tools follow a consistent verb_noun snake_case pattern (e.g., email_validate, url_validate). The use of 'match' for regex is a minor variation but still fits the pattern, and overall naming is predictable.
Four tools is a well-scoped number for a validation utility server. It covers the main advertised domains without being bloated or too sparse.
The server covers its named areas (regex, email, URL) and adds JSON schema validation. Missing a generic string pattern validator or phone number validator, but the scope is sufficiently covered for common use cases.