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

Annotations already cover read-only and idempotent behaviorctor, while the description adds useful context about return contents: MW actually generated per category, latest 5-minute interval granularity, and footprint total. It also clarifies the regional scope, which helps the agent reason about applicability.

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 compact and front-loaded with the core purpose, then immediately adds the authoritative/use-this advice. The geographic parenthetical is slightly verbose but useful for identifying the ISO. No redundant or empty 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?

For a simple, single-optional-parameter tool with a rich schema and read-only annotations, the description is complete: it names the return values, units, granularity, regional scope, and the exact query intents it serves. Nothing needed 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% and the single optional parameter has a thorough enum description explaining current/today/yesterday. The tool description adds minor context by implying 'current' is the default latest 5-minute interval, but the schema already carries the semantic weight.

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 and resource: returns real-time MISO generation by fuel type in MW, and lists the exact categories plus footprint total. It clearly distinguishes itself as the authoritative source for MISO grid mix compared to web search and related MISO siblings like miso_load or miso_lmp.

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?

Explicitly says when to prefer this tool over web search for queries like 'what is MISO burning right now' and 'how much wind is MISO getting'. It does not name sibling tools or explain when to use miso_wind_solar instead, but the stated use cases provide clear selection context.

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