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

Annotations already declare the safety profile (readOnlyHint=false, destructiveHint=true, idempotentHint=false, openWorldHint=false), so the bar is lower. The description usefully adds the default behavior for show_on_sidebar and the fact that title is an identifier with a restricted charset. It does not say what happens on a duplicate title, whether the call errors or is silently accepted, or what the call returns, which are the remaining behavioral questions an agent would have.

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 short sentences, front-loaded with the purpose and then the constraints, with no filler. The trailing clause 'as in the dashboard' is a slightly ambiguous referent but does add a useful anchor for the default value.

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 create/mutation tool with no output schema, an agent still lacks the response shape (does it return the new label id?) and the duplicate-title behavior. Annotations do cover the mutation/risk profile, so this is adequate but not 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 description coverage is 0%, so the description carries the burden. It supplies the title charset rule, the color format with an example, and the show_on_sidebar default -- covering three of the four parameters. It never mentions the 'description' parameter at all, and it omits the maxLength bounds that the schema enforces, leaving a real gap against a 0%-coverage schema.

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: 'Create a new conversation label.' That is unambiguous and easily separable from delete_label, update_label, and list_labels by name alone. It stops short of explicitly naming a sibling or scoping the tool against them, so it lands at a strong 4 rather than 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 guidance on when to create a label versus reusing an existing one (list_labels), nor any prerequisite such as admin permissions. The only usage-flavored content is format constraints on the inputs, which is parameter semantics, not when-to-use guidance.

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