query_metric_points

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

Annotations establish readOnly/idempotent, and the description adds genuinely non-obvious behavior: a server-side cap can truncate results, and truncated=true means the returned points are an early prefix rather than the full window. That is the key caveat an agent needs before drawing conclusions from partial data. It does not mention ordering or what a point object looks like, keeping it from a 5.

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 sentences, front-loaded with what is returned and the identity key, then the prerequisite, then the truncation caveat. No filler or restatement of the tool name.

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?

With no output schema, the description still covers the essential return semantics (points plus a truncation flag) and the discovery prerequisite. Minor gap: it says nothing about point ordering or how to page past a truncated window, which an agent would need for complete coverage of a capped result set.

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 coverage is 100% and each parameter already carries a description including enum-free kind values and the empty-string anonymous scope. The description adds only the framing that the four fields together form a key and that the window must be UTC — modest value on top of a fully documented schema, so the baseline 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?

Specific verb and resource: 'return the points of a single instrument time-series', with the exact composite key that identifies it. It is easily distinguished from list_metrics (discovery) and from the query_logs/query_traces siblings, which target different signal types.

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?

'Use list_metrics first to discover the four-field key' names the prerequisite discovery step and the sibling that supplies it. No explicit when-not-to-use guidance, but for a lookup tool gated on a composite key the sequencing instruction covers the main misuse risk.

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