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

The annotations already declare readOnly, idempotent and non-destructive behavior, so the description is not required to re-state safety. It adds genuinely new behavioral context: ATC values can legitimately be negative and some values are unknown, and the agent is instructed to preserve both rather than sanitize them. It does not describe pagination or units-of-time granularity, but the output schema covers the return shape.

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?

Four short sentences, front-loaded with the core purpose and unit before the caveats. Each sentence carries information, though the two-sentence caveat block could be tightened and the dataset-catalog hint would be clearer if it named the actual tool.

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?

The tool is a simple three-parameter read and the output schema plus annotations cover the result shape and safety profile, so the description is close to adequate. The gaps are the unexplained market enum and the vague 'dataset catalog' reference, which an agent must resolve to a concrete listing tool on its own.

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 0%, so the description carries the whole burden of explaining three parameters. It implies the roles of day, market and interface and gives the unit (MW) and the TTC/ATC concept, but never explains the DAM/HAM enum values or the expected format for the interface string beyond pointing at the dataset catalog.

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 gives a specific verb and resource ('Get regional interface TTC/ATC in MW') plus the scoping dimensions (date and market), so the agent knows exactly what data comes back. The sentence 'Interface transfer capacity is not parcel interconnection capacity' explicitly separates it from parcel-related siblings without ambiguity.

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?

It tells the agent where to find valid inputs ('The dataset catalog lists available interfaces/dates'), which functions as a prerequisite/dependency for calling the tool correctly. It also carves out the parcel-interconnection case as out of scope, though it never names which sibling to use for that instead.

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