Discover labels

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety and idempotence are covered. The description adds the dual-mode behavior (list vs. distinct values) and the session-startup role, but says nothing about value cardinality beyond the schema's limit cap or pagination behavior; with an output schema present, that omission is minor.

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; the resource definition is front-loaded, the usage trigger follows, and the motivating example closes. No filler or repetition.

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?

Zero required parameters, a full output schema, and complete annotations mean the agent needs nothing else. The description covers purpose, timing, and both invocation modes, which is everything a discovery tool of this shape requires.

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 all three parameters are already documented in detail. The description's 'pass a label name to get its distinct values' largely restates the label property's own schema text, so it adds framing rather than new semantics. 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?

States a specific verb ('List') and resource ('labels Log10x metrics can be filtered or grouped by'), plus the second operating mode ('pass a label name to get its distinct values'). An agent immediately understands the resource is label metadata, distinguishing it from sibling tools like log10x_discover_env or log10x_services.

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 prescribes when to call it: 'at the start of a session, or before calling any tool that takes a label/filter argument.' It also gives the concrete failure mode it prevents (guessing 'namespace' when the real name is 'k8s_namespace'), which is the strongest possible justification for the timing guidance.

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