Add a user as a watcher to a Jira issue, enabling them to receive notifications about updates and comments.
Add a user as a watcher of an issue
| Name | Required | Description | Default |
|---|---|---|---|
| key | Yes | issue key, e.g. PROJ-123 | |
| username | Yes | Username. Jira Server uses `name`, not the Cloud `accountId` |
Changes observed during successful MCP inspections.
v1.0.5Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The only annotation is readOnlyHint=false, which just confirms this is a write. The description adds nothing beyond that: it doesn't disclose idempotency (does adding an existing watcher fail or no-op?), permission requirements, or whether the watcher is notified. Minimal but not incorrect.
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 front-loaded sentence with zero filler. Nothing to trim and nothing misplaced.
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 mutation tool with no output schema and only a readOnlyHint=false annotation, the description leaves too much unspecified: idempotency behavior, required permissions, and whether notifications fire. The schema covers inputs fully, but the behavioral surface of the write is undocumented.
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 both params are well documented in the schema (key pattern, username Server-vs-Cloud note). The description contributes no additional parameter meaning, 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?
Precise verb+resource: 'Add a user as a watcher of an issue'. An agent can immediately distinguish it from jira_get_watchers (read) and jira_remove_watcher (removal) without opening a schema.
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 mutating verb 'add' – this is the action to take when a user needs to watch an issue. But the description names no alternative, no prerequisite (issue existence, user existence), and no when-not condition. Sibling jira_get_watchers and jira_remove_watcher are not referenced.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.