get_daily_totals

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

Beyond the readOnlyHint, idempotentHint, and destructiveHint annotations, the description adds valuable behavioral context: it specifies that unavailable meters are represented as null, and explicitly lists the four totals returned. This informs the agent about response semantics, which is not captured in annotations.

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 concise (three sentences), front-loads the core purpose and read-only nature, and each sentence adds essential information: what it does, what it returns, and null handling. There is no fluff or redundancy with the schema.

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 simple, no-parameter, read-only tool with an output schema, the description is complete. It covers the operation, scope, return values, and edge-case behavior (null for unavailable meters). No additional context is needed, and the output schema handles return format details.

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 tool has zero parameters, so the input schema is trivially covered at 100%. The description correctly does not attempt to explain parameters. The baseline for 0 params is 4, and the description adequately conveys that no arguments are needed.

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 tool's purpose with a specific verb ('Get'), resource ('today's cumulative energy totals'), and unit (kWh), and distinguishes it from siblings by focusing on daily cumulative totals. It also enumerates the returned components (generation, consumption, grid-buy, grid-sell), making the scope unambiguous.

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 implies usage by stating it returns today's totals, but it does not provide explicit guidance on when to use this tool over siblings like get_history or get_power_flow. No alternatives or exclusions are mentioned, so usage is only inferred rather than directly instructed.

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