Everyday DevTools MCP

cron_next

Calculate the next scheduled run times in UTC for any standard 5-field cron expression, so you can verify a schedule before deploying it.

Instructions

Show the next run times (UTC) for a standard 5-field cron expression.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "expression": "<expression>"
    },
    "name": "cron_next"
  }
}

Input Schema

Name	Required	Description	Default
`count`	No
`expression`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Nov 9, 2026

TDQS

A3.6/5.0

Behavior3/5

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

With no annotations, the description carries the full burden, and it does add real behavior context: results are in UTC and only standard 5-field expressions are accepted. However, it says nothing about what happens on a malformed expression, whether output is a list/array, or any upper bound on returned times.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler. The key constraint (UTC, 5-field cron) appears before any subordinate detail, and every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a simple stateless computation with no output schema and no annotations, the description covers the core contract (returns next run times, UTC, 5-field format). It falls short on the 'count' parameter's effect and error behavior for invalid expressions, both of which an agent needs to call it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description must compensate. It loosely identifies the 'expression' parameter as a 5-field cron string, but the 'count' parameter — which controls how many run times are returned, defaulting to 5 — is never mentioned, leaving its meaning and limits entirely undocumented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific verb ('Show'), a specific resource ('next run times'), and a scope ('standard 5-field cron expression') with a timezone qualifier (UTC). No sibling tool computes cron schedules, so the purpose is unambiguous against the utility-tool family.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: an agent can infer it should call this when it needs upcoming execution times. There is no explicit when-to-use, no statement of exclusions (e.g., 6-field or Quartz expressions are not supported, which is only hinted at by 'standard 5-field'), and no guidance on alternatives or invalid-input handling.

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

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