hey_label

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

Annotations already declare the mutation profile (readOnly=false, destructive=false, idempotent=true), but the description adds real value by disclosing the return shape ({success, error?}) despite no output schema, and by explaining reversibility. It doesn't cover auth requirements or rate limits, but the added context is substantive.

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?

Three tight sentences with zero filler: the action is front-loaded, the return shape follows, and the discovery pointer closes it out. Every sentence earns its place.

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 3-param mutation tool with full schema coverage but no output schema, the description supplies the missing return shape, reversibility semantics, and ID discovery path. Nothing an agent needs to invoke it correctly is absent.

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 100%, so the enum, label_id, and topic_id are fully documented in the schema. The description's only param-related guidance (use hey_list_labels for IDs) duplicates the label_id schema description, so there is no net addition beyond structured 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?

States a specific verb pair (add/remove) and resource (label on an email thread), which is unambiguous and distinct from siblings like hey_set_aside or hey_move_to. An agent can tell immediately what this tool does without reading further.

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 routes the agent to hey_list_labels to discover available label IDs before calling. It gives clear prerequisite context, though it doesn't contrast against similarly-scoped siblings like hey_set_status or explain when labeling is preferable to those alternatives.

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