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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine value by asserting 'Official data with its source' (provenance is returned), but it says nothing about response shape, pagination, missing-data behavior, or freshness/lag beyond the day/month/year snapshots.

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?

A single, densely packed sentence with zero filler and the most important content (what data, which regions, which sources) front-loaded. It is slightly run-on, listing tensors of detail inline rather than breaking out the optional history clause, but no sentence is wasted.

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?

With no output schema, the description carries the return-value burden and does so well — it spells out the snapshot points, the spread definitions, the optional weekly series, and the attached source attribution. The main remaining gap is that it does not describe the structure of those returns (per-region objects, tenor grid) or whether data is cached/dated.

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 coverage is 100%, so all three parameters are already documented with defaults, date format, and the 1990 backstop. The description reinforces which outputs the optional weekly history activates (2y/10y/2s10s) and lists the region codes, but adds no syntax or constraint 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 exact resource (government bond yield curves) and enumerates the covered jurisdictions with their official sources (US Treasury, ECB AAA, BoE, MoF), plus the concrete payload: per-tenor yields at four snapshots, 2s10s/3m10y spreads, optional weekly history. It is clearly distinguishable from siblings like get_policy_rates or get_economic_indicators, though it never explicitly contrasts itself with them.

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?

Usage is implied by what the tool returns — an agent can infer it should call this for curve levels, spreads, or curve history — but there is no explicit when-to-use statement, no exclusion, and no routing to alternatives such as get_policy_rates for policy rate context.

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