jira_update_issue

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

With no annotations, the description carries the full disclosure burden. It explains partial-update behavior ('only provided fields are updated'), that labels replace existing ones, and that assignee format differs by platform (accountId on Cloud vs username on Server/DC). It does not mention potential destructive implications or permission requirements, but adds meaningful behavioral context beyond 'Update fields'.

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 efficiently organized: a one-sentence purpose, a few context notes, an Args list with per-parameter explanations, and a Returns line. It avoids fluff, though the parameter list is lengthy; however, this length is justified given the 0% schema coverage. It is front-loaded with the main behavior.

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 high complexity (8 parameters, no annotations, no output schema), this description is remarkably complete. It covers the purpose, all parameters, return value, and critical edge cases like Cloud/Server assignee differences and label replacement. It leaves little ambiguity for correct invocation.

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 description coverage is 0%, so the description compensates fully by listing each parameter with a meaningful explanation: issue_key with format example, assignee with platform-specific format, labels with replacement semantics, comment with timing, and custom_fields as a dictionary. This adds substantial meaning beyond the schema's bare type/title fields.

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 opens with 'Update fields on an existing JIRA issue' — a specific verb+resource that clearly distinguishes it from sibling tools like jira_create_issue, jira_search_issues, or jira_transition_issue. It further clarifies scope by noting all field parameters are optional and that a comment can be added in the same call.

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 gives clear context: use it to update fields on an existing issue, with all fields optional, and notes the Cloud vs Server/DC distinction for assignee. However, it does not explicitly state when to use an alternative (e.g., jira_transition_issue for status changes) or provide exclusion criteria.

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