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

Annotations already provide readOnlyHint=true, so the safety profile is covered. The description adds that the tool returns hourly or daily averages, which is useful behavioral context, but this largely restates the schema's period descriptions and does not disclose additional traits like response shape, limits, or output units.

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 short sentences with no filler. The core action and resource are front-loaded, the aggregation behavior follows, and the use case is stated last. Every sentence 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?

For a two-parameter read-only tool with full schema coverage, the description covers purpose, aggregation granularity, and intended use. It does not define the exact response structure, which matters more because there is no output schema, but the level of detail is sufficient for a simple chart-data retrieval tool.

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 parameters monitor_id and period are already fully documented. The description repeats the period options without adding new meaning, so it does not elevate the baseline.

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 verb and resource: 'Get response time time-series data for a specific monitor.' It also adds the aggregation periods (hourly for 24h, daily for 7d), making the tool's purpose unambiguous. It does not explicitly differentiate from related getters like get-uptime-stats or get-page-speed, so it stops short of a 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?

'Useful for spotting performance trends' gives a clear use context for when an agent would select this tool. It does not mention exclusions or alternative sibling tools, but the stated use case is concrete enough to guide invocation.

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