Energy history

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds meaningful details about the output shape for each period (which metrics are returned for 'day' versus totals for other periods), but it does not address behaviors like timezone handling, response pagination, or units. Given the annotation coverage, this is an adequate level of transparency.

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?

The description is a single, dense paragraph that front-loads the resource and action, then cleanly enumerates the four period cases with their date formats and return types. Every clause earns its place, with no redundant restatements of the schema or annotations.

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 tool with no output schema, the description provides everything an agent needs to invoke it correctly: the required period parameter, the date format for each period variant, defaults for optional date and plant_id, and a high-level description of what each period returns. Units and timezone details are minor and do not block correct usage.

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?

The input schema already documents all three parameters (100% coverage), so the baseline is 3. The description adds value by mapping each period enum value to its required date format (YYYY-MM-DD, YYYY-MM, YYYY) and explaining default behavior for date and plant_id. This goes beyond the schema's terse labels like 'Granularity'.

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 this tool returns 'Energy history for a plant' and then specifies exactly what each period value yields (intraday power curves, daily kWh totals, monthly totals, yearly totals). This level of specificity makes the tool easy to distinguish from siblings like sunsynk_live_status or sunsynk_power_flow, which are for real-time/current data.

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?

The description establishes a clear context for use: any request for historical energy data at day/month/year/total granularity. It does not explicitly name alternatives or say when not to use it, but the historical framing is distinct from the live-status siblings. No exclusions are provided, so it stops short of a 5.

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