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

With no annotations, the description carries the full behavioral burden and provides very little: it does not explain what "PRO" means, whether a subscriber token is required, whether results are ordered, how fresh the data is, or what the response looks like. The approximate count "~15" is disclosed, but that alone is thin for an unannotated tool.

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 short and front-loaded, but "PRO." consumes the opening position without conveying usable meaning. The remaining fragment is terse but not structured enough to explain the tool's role.

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 one-parameter tool with no output schema, the description gives the return scope (last ~15 observations), which is useful. It still leaves the "PRO" qualifier, authentication expectations, and result ordering unclear, so it is only minimally complete.

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 sole parameter access_token is fully documented in the schema (100% coverage), so the schema already carries parameter meaning. The description adds no parameter-level detail, which is acceptable at this coverage level but earns only the baseline.

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?

"Last ~15 cash-rate observations" identifies the resource and the recency window, so the agent can infer it returns recent observations. However, the leading "PRO." is unexplained jargon rather than a verb, and the description does not distinguish this tool from siblings cash_rate or column.

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?

No guidance is given on when to use this tool versus cash_rate or column. The name "recent" and the phrase "Last ~15" imply a recency-limited variant, but the description never states the condition that should select it over the full cash_rate tool.

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