update_issue

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

Annotations already indicate mutation and idempotency. The description adds value by explaining that arguments are independent and labels are replaced atomically, going beyond what annotations provide. However, it does not mention potential side effects like notifications.

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?

Two sentences: first lists updatable fields, second explains independence and replace semantics. Every sentence is essential, no wasted words, and the purpose 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?

Given the tool's complexity (9 parameters, output schema present), the description covers the core behavior and usage pattern. It could mention prerequisites like issue existence or permissions, but the existing info is sufficient for typical use.

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% with parameter descriptions. The description adds meaning by stating independence of arguments and the replace semantics for list fields, which clarifies usage beyond the schema's 'New title' or 'Replace labels' descriptions.

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 clearly states the tool updates an existing issue's specific fields (title, body, state, assignees, milestone, labels). It distinguishes from siblings like create_issue, get_issue, and list_issues by focusing on mutation of an existing issue.

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 explicitly says 'pass only the fields you want to change' and explains replace semantics for labels and assignees. It provides clear context for usage, though it does not explicitly state when not to use or name alternatives, but the sibling tools are distinct enough.

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