query_history_trend_runs

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

readOnlyHint=true already establishes this is a safe read. The description adds the return ordering ('slowest first') and the bucket granularity, which is useful behavior beyond the annotation, but it says nothing about result size, limits, or how failed_only filters.

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?

A single front-loaded sentence that identifies the resource, the bucket union type, and the sort order with no waste. Slightly terse but nothing is padding.

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?

No output schema exists, but the description needn't explain returns since it already states ordering. It covers the critical bucket format, yet the failed_only parameter goes unexplained and there is no note on result volume for a potentially large drill-down query.

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 compensate. It does document the required bucket format (day 'YYYY-MM-DD' or hour 'YYYY-MM-DD HH'), which is genuinely valuable, but failed_only is left entirely undecoded in both schema and description.

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?

It states a specific resource (the queries behind one Trends bar) and scope, distinguishing it from the sibling query_history_trends which produces the bar itself. An agent can tell this is the drill-down tool, though it uses a noun phrase rather than an explicit verb.

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 'behind one Trends bar' – the agent infers it is called after viewing a trend, for a specific bucket. There is no explicit when-to-use, no exclusions, and no reference to how failed_only changes the selection.

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