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

Annotations already declare read-only, idempotent, open-world, and non-destructive behavior. The description adds substantial context beyond them: the returned fields (US Eastern, UTC, local time), default London timezone, BLS source, limitation to dates, and 1-credit cost. It does not contradict any annotation.

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 front-loaded with the core question and then efficiently lists return fields, source, limitation, and cost. Every sentence contributes useful selection or invocation context.

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 low-complexity, single-parameter tool with no output schema, the description covers purpose, return values, source, timezone behavior, limitation, and cost. Nothing material 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?

The single optional timezone parameter is fully documented in the schema, including IANA format and default Europe/London. The description reinforces that the parameter controls local-time output and that US Eastern and UTC are also returned, but adds little syntax or semantic detail beyond the schema.

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 names the specific resource (Employment Cost Index) and the exact question it answers, defines ECI as quarterly US wage and benefit costs, and states it returns release dates rather than index values. This is enough to separate it from sibling release-date tools such as next_cpi_release without needing an explicit sibling comparison.

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 makes the intended use clear: retrieve the next ECI release date and following scheduled dates. It also sets a boundary by saying it gives dates only, not index values, though it does not explicitly name an alternative tool for CPI/GDP/etc. release dates.

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