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

With no annotations, the description carries the full burden and does so well: it discloses the Datakoot caching/warm-keep behavior, that BLS rate-limits by client IP shared across Datakoot's edge, and crucially how to interpret the upstream-limit error (refusal, not missing series). This is exactly the operational context an agent needs to avoid misdiagnosing failures.

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 purpose and the key list before the operational caveat. It is efficient, though the series enumeration is duplicated from the schema, which is mild redundancy rather than waste.

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?

There is no output schema, yet the description says nothing about the return shape: frequency, units, observation count, or freshness of the series. Input selection and error handling are fully covered, but an agent cannot anticipate what data structure comes back, leaving a real gap for a time-series tool.

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 single 'series' parameter is already fully documented. The description repeats the accepted keys and adds only the rate-limit caveat, which the schema also mentions, so it does not meaningfully extend the schema's semantics. 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 ('Get') plus resource ('a key US economic time series') and enumerates the exact series keys, which immediately separates it from country-level siblings like country_indicator and country_profile. An agent knows from the first sentence that this is US-specific series retrieval, not country 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?

Gives clear context for which keys exist and when to prefer the cached keys over a raw BLS ID, including the explicit caveat that uncached series may fail. It stops short of naming a sibling alternative or stating when to use country_indicator instead, so it is clear but not fully routing.

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