Update issue

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

Annotations (destructiveHint=true, readOnlyHint=false) already flag this as a mutating operation, and the description builds on them by disclosing exactly what gets destroyed: 'description replaces the WHOLE rich-text field, so tables and panels in the old value are lost' and 'labels replaces the whole list.' It also adds null semantics (un-parents, unassigns), format interpretation, and the status exclusion — all context beyond what annotations convey. No contradiction with annotations.

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?

Four dense sentences, each carrying a distinct payload: core purpose, destroy-risk warning, null semantics, format rules, and the sibling-tool pointer for status. Nothing is repeated from the schema, and the highest-risk information (REPLACE semantics) is front-loaded.

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 15-parameter, destructive write tool without an output schema, the description covers all major behavioral traps: replace semantics, incremental alternatives, null clearing, markdown parsing, and the status exclusion. The only gap is that it never states what the call returns (e.g., the updated issue), which matters more here because no output schema exists to convey it — a minor omission against an otherwise complete definition.

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 93%, so the schema already documents most parameters well and the baseline is 3. The description earns credit for clarifying parameter interplay the schema cannot express as a strategy: the tension between labels (whole-list replace) versus labelsAdd/labelsRemove (incremental), and the coupling of format to string description input. The added value is modest but genuine.

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 a specific verb+resource pair ('Update fields on one issue') that names exactly what the tool does. It differentiates from sibling tools by explicitly stating 'Status is not settable here — use jira_transition_issue,' which addresses the biggest overlap risk among the 50+ Jira tools.

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 explicit routing guidance: 'use labelsAdd / labelsRemove for incremental edits' and 'Status is not settable here — use jira_transition_issue.' It also warns against the wrong usage pattern ('never "append" a paragraph this way'), which is as actionable as positive guidance.

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