instant_query

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

With no annotations, the description carries the full burden. It discloses the response structure (evidence block with exact query, execution time, series/sample counts, warnings) and mandates citation of that evidence. It does not mention side effects, rate limits, or auth, but for a read-only query tool this covers the most important behavioral aspects.

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 description is two sentences with zero fluff. It front-loads the core purpose ('Run an instant PromQL query') and then adds the critical response/citation detail. Every word 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?

Given there is no output schema, the description explains the response's key components (evidence block) and the mandatory citation behavior. It also covers the instant evaluation nature. It omits potential error handling or edge cases, but for a straightforward query tool this is sufficient for an agent to call it correctly.

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 both parameters (promql and time) are already documented. The description does not add parameter-specific detail beyond the schema, which is acceptable; the baseline of 3 applies.

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 clearly states the tool runs an instant PromQL query, specifying the verb 'run' and the resource 'PromQL query'. The word 'instant' distinguishes it from likely time-range siblings like range_query, though it does not explicitly name them, so it's not a perfect 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?

The description implies the tool is for point-in-time queries via the word 'instant', but it does not explicitly state when to use this tool versus alternatives like range_query or list_metrics. There is no direct comparison or exclusion of sibling tools, leaving some inference to the agent.

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