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

No annotations exist, so the description carries the full burden; it does disclose the return cardinality (~10), ordering ('last'), and a paid/subscriber access gate. It omits what happens when no access_token is supplied (the schema marks it optional), error behavior, and the shape of returned observations.

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?

Two terse fragments with no waste, but 'PRO.' is front-loaded ambiguity rather than purpose, and 'JGB' is left unexpanded, making the statement cryptic for an agent without domain knowledge.

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 one-parameter read tool the description is minimally survivable, but with no output schema it says nothing about the returned fields (dates, tenors, yields) and leaves the duplication with 'latest_yields' entirely unresolved.

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?

Only one parameter and schema description coverage is 100%, so the schema already explains access_token fully. The description adds nothing about it beyond the redundant 'PRO' signal, which is the baseline case for full schema coverage.

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 resource (JGB yield observations) and its scope (the ~10 most recent), which is more than the opaque tool name 'recent'. But it never distinguishes this from the near-identical sibling 'latest_yields', so an agent cannot tell from the text which one to call.

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?

There is no guidance on when to use this versus 'latest_yields' or 'tenor', despite 'latest_yields' sounding like a direct substitute. The 'PRO' prefix implies a paid tier but is not explained as a usage prerequisite.

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