Query a datasource

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so 'Reading data only — this never mutates anything' largely restates structured data. It does add one useful behavioral fact (results come back as result frames) and performance guidance about bounding time range/maxDataPoints, but says nothing about auth needs, rate limits, or error behavior for a mutating-adjacent remote call.

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 the core action, then dialect-specific parameter selection, then a practical constraint. No filler; every clause carries actionable information.

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 query tool with full schema coverage and read-only/idempotent annotations, the description covers purpose, parameter selection, and safety sufficiently; with no output schema, the brief mention of 'result frames' is adequate but thin. Minor omission: no guidance on result size, pagination, or failure modes.

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 the baseline is 3, but the description adds the conditional mapping between expr (PromQL/LogQL) and rawSql (SQL) that the schema documents only in isolation. It does not clarify from/to formatting or maxDataPoints tradeoffs beyond what the schema already states.

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 ('Run a query against a datasource through Grafana's unified query API and return the result frames'), and the sibling set (list_*/get_* tools) is clearly non-overlapping, so the agent can route here without ambiguity. It also names the two query dialects it supports, which sharpens what 'query' means.

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 tells the agent which parameter to use per datasource family ('for Prometheus/Loki set expr ... for SQL datasources set rawSql') and advises a bounded time range with small maxDataPoints. It lacks any when-not-to-use or alternative-tool routing, but no sibling overlaps this capability.

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