Add labels to issue

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the safety profile is covered externally. The description adds one useful behavioral detail — labels are supplied by ID rather than name — but says nothing about whether the change is additive (it is implied by 'add'), whether it needs write permissions, or how duplicates are handled.

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 ten-word sentence that front-loads the action and target with zero filler. Nothing could be removed without losing information.

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 four-parameter, fully-required mutation tool with no output schema, the description covers the basic action but omits additivity semantics, permission requirements, and what the response contains. Annotations cover safety, so the gap is not severe, but the definition is only minimally complete.

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 75%, with the required 'labels' array being the one property that carries no schema description. The parenthetical '(by ID)' partially compensates by telling the agent to pass label identifiers rather than names, which is genuine added meaning, but it gives no help on where those IDs come from. Baseline 3 is appropriate.

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 gives a specific verb and resource ('Add labels') plus the target entity ('issue or pull request'), so the agent knows exactly what is operated on. It does not explicitly distinguish itself from the sibling 'remove_issue_label' or explain how it relates to 'create_label', so it stops short of a 5.

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?

There is no when-to-use or when-not-to-use guidance, no mention of prerequisites such as needing the label to already exist, and no reference to alternatives like 'list_labels' (to discover IDs) or 'remove_issue_label' (the inverse operation). The agent must infer all routing from the tool name alone.

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