add_label_to_thread

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

With no annotations, the description must cover behaviors. It states the action but does not disclose idempotency, overwrite behavior, permissions, or response format. Sufficient for a simple add operation but could be more transparent.

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 concise sentences front-loaded with the action and resource, zero wasted words.

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?

Adequately covers the tool's purpose and prerequisite step (list_labels). Lacks details on results or side effects, but sufficient for a straightforward label assignment.

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 descriptions for all params. The description adds usage context but no extra parameter-level detail beyond the schema, warranting baseline 3.

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 action ('Add') and the resource ('shared label to an email thread (or task)'), distinguishing it from siblings like remove_label_from_thread or toggle_labels.

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?

Explicitly advises using list_labels first to find available label IDs, providing clear prerequisite guidance. Does not explicitly state when not to use it, but the context is sufficient.

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