cron-explainExplains a 5-field cron expression in plain English (UTC, as Cloudflare runs it). Returns { cron, explanation }: the expression and a plain-English reading of it. Price: 1 credit (1 credit = 1 CAD cent) per successful call; input that does not match the schema is rejected before billing.
| Name | Required | Description | Default |
|---|---|---|---|
| cron | Yes | Five-field cron expression (minute hour day-of-month month day-of-week), read as UTC like Cloudflare Cron Triggers. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and openWorldHint=false, so the description's real contribution is the commercial and failure behavior: 1 credit per successful call, and schema-invalid input is rejected before billing. That is genuinely non-obvious context an agent needs. It doesn't cover error responses for valid-but-unparseable expressions (e.g. an impossible date), which is the one 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?
Three sentences: purpose first, return shape second, cost/billing last. Nothing is redundant and every sentence carries information an agent can act on.
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?
For a single-parameter, read-only transform tool, this covers purpose, dialect, output shape, and billing semantics, with annotations handling the safety profile. No output schema exists, yet the description still names the two returned fields, so nothing material is missing.
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 coverage is 100% and the single cron parameter is fully documented in-schema, including the five-field ordering and UTC interpretation. The description restates "5-field" and UTC but adds no syntax hints (ranges, steps, lists, macros) beyond what the schema already says, so baseline 3 applies.
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 and resource ("Explains a 5-field cron expression in plain English") and pins the dialect with "UTC, as Cloudflare runs it", which separates it from the cron-to-cf sibling that converts rather than explains. The return shape ({ cron, explanation }) is named directly, so the agent knows exactly what comes back.
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?
Usage is implied by the verb — you call it when you have a cron expression you need in English — but there are no explicit when/when-not statements and no mention of cron-to-cf as the alternative for conversion. The billing and rejection rules give useful context for deciding to call, but not routing guidance against siblings.
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.