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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantive context beyond them: response capped at 750 points, explicit ranges capped at 730 days, and 10 read units per call billing cost. It also discloses data conventions (S.A. basis, EUR spreads over Bund on annual basis), which an agent needs to interpret results correctly.

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 core purpose is front-loaded in the first sentence, and the remaining clauses on yield basis, caps, and billing each add needed information. The EUR-exception sentence is dense and parenthesis-heavy, but nothing is redundant.

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 an output schema present, return values need no explanation, and the description covers range caps, point caps, billing, and yield conventions. What's missing is identifier format and date-boundary semantics — the two things most likely to cause a failed call.

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 0%, so the description must carry the load; it clarifies that range is a 'named range' alternative to explicit start/end, and defines units for the returned fields. However it never states what an identifier accepts (ISIN/CUSIP/ticker), whether start/end are inclusive, or precedence when range and dates are both supplied — significant gaps for a required parameter.

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?

Specific verb plus resource: 'Return daily price, YTM, YTW, and spread history for one bond.' An agent immediately knows this is a time-series tool, which implicitly separates it from snapshot siblings like get_bonds or get_terms. It never names or contrasts a sibling explicitly, so it stops short of a 5.

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 explains the two input modes ('using a named range or explicit dates') and the 730-day cap, which is real usage guidance for parameters. But there is no explicit when-to-use / when-not-to-use statement versus siblings such as treasury_curve or get_bonds, leaving tool selection to inference.

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