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

With no annotations, the description carries the full burden and does disclose the calculation methodology (eGRID subregion rate for location-based, Green-e residual mix for market-based) and the return shape (kg CO2e per method with factors used). It omits operational traits like determinism, rate limits, or permissions, but for a read-only computation this is solid disclosure.

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 sentences, front-loaded with the verb and resource, then methodology, then return value. Every sentence earns its place with no filler.

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?

With no output schema, the description steps in to describe the return value (kg CO2e for each method plus factors), and it explains the calculation basis. A few details (units per input, whether year affects the market-based path beyond the schema note) are left to the schema, but nothing essential for correct invocation 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 schema already documents zip, kwh, year, and renewable_kwh, including the market-based zero-counting rule. The description's mention of kWh 'not covered by RECs, PPAs or green tariffs' largely restates the renewable_kwh schema text, adding little beyond it. Baseline 3 applies.

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 (Calculate) plus a precisely scoped resource (Scope 2 CO2e for a facility) and enumerates the two GHG Protocol methods. An agent can distinguish it from calculate_fuel_emissions or lookup_emission_factor without opening the 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 clear context that this is a facility-level Scope 2 electricity calculation covering both location- and market-based methods, so no method selection is required. It does not name siblings or state when-not to use it, leaving explicit routing to inference.

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