compare_isos

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds behavioral context: lists exact return fields and the as_of timestamp. It does not contradict annotations. Some missing details (e.g., error handling) but overall adds sufficient value beyond 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 a single dense paragraph but well-organized: starts with usage, provides example, then parameter format. Slightly redundant in documenting the 'isos' parameter twice (schema and text) but front-loaded with key purpose. Could be slightly more structured, but still efficient.

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 one parameter and no output schema, the description covers all essentials: usage context, input format, valid values, expected output structure with fields, and exclusions. No gaps remain for the agent to infer.

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 has 100% description coverage for the only parameter. The description adds further meaning: specifies comma-separated format, max 4 ISOs, and explicitly lists the 7 valid US ISOs (PJM, ERCOT, CAISO, MISO, SPP, NYISO, ISO-NE), which is more precise than the schema's description.

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 compares 2-4 ISO grids side-by-side, listing specific metrics (fuel mix, demand, renewable/gas share, etc.). It explicitly distinguishes from siblings: 'Do NOT use to rank ALL grids globally (use get_grid_scoreboard) or for the single-ISO deep brief (use get_grid_intelligence).'

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?

Description explicitly says 'Use when a user wants a side-by-side of 2-4 ISO grids' and provides a concrete example. It also tells when NOT to use and names alternative tools (get_grid_scoreboard, get_grid_intelligence), leaving no ambiguity.

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