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

Annotations already declare readOnlyHint=false, idempotentHint=false, and destructiveHint=false, so the safety profile is covered. The description adds a valuable behavioral fact the annotations do not carry: the operation requires admin privileges. It stops short of covering duplicate-name behavior, which matters given idempotentHint=false.

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 short sentences with zero waste. The action is front-loaded and the permission constraint follows immediately. 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?

An output schema exists so return values need not be explained, and the schema fully documents parameters while annotations cover the safety profile. The only meaningful gap is what happens when a label with the same name already exists, which is relevant given idempotentHint=false.

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%, with all three parameters documented including format hints ('#RRGGBB', 'like "bug"', 'A project key'). The description adds nothing about parameters, so the baseline of 3 is appropriate when structured fields do the heavy lifting.

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 and resource: 'Adds a label to a project.' An agent can immediately tell this creates a label scoped to a project. It does not differentiate from siblings, but no sibling tool overlaps with labels, so differentiation is largely moot.

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?

'Admins only' is a genuine prerequisite that constrains who should call it, which is real usage guidance. However, the description names no alternatives and gives no guidance on when to create a label versus using existing ones, leaving usage largely implied.

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