jira-mcp-server

create_subtask

Creates a Jira subtask under a specified parent issue using the parent issue key and a summary, with optional description and issue type.

Instructions

Create a subtask for a parent issue

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": {
      "parentIssueKey": "<parentIssueKey>",
      "summary": "<summary>"
    },
    "name": "create_subtask"
  }
}

Input Schema

Name	Required	Description	Default
`summary`	Yes	Short summary of the subtask
`issueType`	No	Subtask issue type name	Sub-task
`description`	No	Detailed description
`parentIssueKey`	Yes	The key of the parent issue

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Aug 8, 2026

TDQS

C2.9/5.0

Behavior2/5

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

Since no annotations are provided, the description carries the full burden of behavioral disclosure. It merely says 'Create' and does not mention side effects, permissions, or any other behavioral characteristics beyond the obvious mutation.

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

Conciseness4/5

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

The description is a single, clear sentence with no wasted words. It is concise and front-loaded, but it is also minimal and does not provide extra value beyond the tool's name.

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

Completeness2/5

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

Given the tool has four parameters, no output schema, and no annotations, the description is inadequate. It does not explain return values, prerequisites, or how the subtask relates to the parent issue, leaving significant gaps for the agent.

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

Parameters3/5

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

The schema description coverage is 100%, so all four parameters are already documented in the schema. The description adds no additional meaning or context for the parameters, keeping the baseline score at 3.

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

Purpose4/5

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

The description clearly states the verb 'Create' and the resource 'subtask for a parent issue,' which is specific and distinguishes the tool's purpose from general issue creation. However, it does not explicitly differentiate it from the sibling create_issue tool.

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

Usage Guidelines2/5

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

No guidance is provided on when to use this tool versus alternatives such as create_issue or bulk_create_issues. The description only states the basic action without any context, prerequisites, or exclusion criteria.

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