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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so the safety profile is covered structurally. The description adds useful disclosure about what the response contains (comparisons, zone changes, anomaly share, sensors that switched on/off), which goes beyond the annotations, but says nothing about default behavior when `to` is omitted or how large ranges are handled.

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?

Two sentences with the payload described first and the usage trigger second, which is the right front-loading. The enumeration is dense and slightly run-on, but every clause names something the agent actually gets back.

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 return content, and it does so field-by-field (market shock from→to, zone change, anomaly share, top movers, on/off sensors, filters). Combined with annotations and a fully documented two-parameter schema, an agent has everything needed to call it correctly.

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 both parameters already carry pattern and default documentation, so the schema does the heavy lifting. The description's phrase 'between two dates' confirms the range semantics but adds no new meaning beyond the schema 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 gives a specific verb-and-resource framing ('what moved between two dates and why') and enumerates the payload (per-instrument market shock with from→to and zone change, market-anomalies share, biggest-moving sensors, on/off transitions, filters). It is clearly a date-range diff tool, distinct from point-in-time siblings like get_readings_on_date or get_current_readings, though it never names those siblings explicitly.

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?

It gives concrete triggering contexts: the user previously asked ('since last week / since I last checked') or asks why a reading changed. That is a real routing signal against get_readings_on_date and get_monthly_history. It stops short of explicit when-not-to-use or naming alternatives.

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