loki_label_values

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

readOnlyHint=true already tells the agent this is a safe read, so the [READ] tag is redundant. The description does add real context beyond the annotation: results are 'bounded' and the hours window is 'capped at the tool's max lookback.' Return shape and pagination/truncation behavior remain unspecified, so it lands at adequacy rather than richness.

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?

The purpose sentence is front-loaded in one line, followed by a compact Args block; every line carries information. Minor overhead is the '[READ]' tag already covered by annotations.

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-parameter read-only tool with no output schema, the description covers purpose, all parameters, and the bounding/cap constraints. Only the result shape and whether values are truncated are left unstated.

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 must carry all parameter meaning — and it largely does: 'name' is a label name with concrete examples ('app', 'namespace'), 'hours' is a lookback window with a cap caveat, and 'target' is a config-defined Loki target with 'omit for the default'. It compensates well for the empty schema descriptions, missing only the default value for hours.

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 states a specific verb and resource: enumerating distinct values of one Loki label, with a [READ] tag marking it non-mutating. It implies a difference from siblings like loki_labels (which would list label names) and label_values (the Prometheus counterpart), but never names those siblings explicitly.

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?

Usage is implied by 'Distinct values of one Loki label' — an agent can infer this is for value discovery on a known label — but there is no explicit when-to-use, when-to-use-something-else, or prerequisite guidance, and no routing against loki_labels or label_values.

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