zabbix_metrics_history

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is covered. The description adds value the annotations don't: the window-syntax convention operators use and the aggregation semantics (min/max/average) of the returned data. It omits mention of truncation, though the schema's limit description covers that.

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, front-loaded with purpose, then syntax convention, then usage routing. No filler and nothing that fails to earn 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?

There is no output schema, so the description carries the burden of describing returns, and it does: min, max and average over the window. Combined with annotations covering safety and the schema covering all params, nothing an agent needs to call this correctly is missing.

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, and every parameter including defaults, bounds and examples is already documented. The description goes slightly beyond by framing the 'last' window in operator-friendly terms (30m, 2h, 24h, 7d), reinforcing how to write the value rather than just the regex.

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 ('Read an item's values over a time window') plus the aggregation produced (min, max, average). It explicitly differentiates from the two nearest siblings, so an agent can distinguish it without opening any schema.

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?

Gives an explicit when-to-use condition ('user asks how a metric behaved over a period, or wants min/avg/max') and names both alternatives with their selecting conditions: zabbix_metrics_latest for the newest value only, zabbix_unreachable for host reachability. Routing is unambiguous.

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