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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is handled. The description adds real value beyond that: unit conventions (percent, basis points, price per 100 face), a response cap of 11 tenors, and billing cost (free, no calculation or read units consumed).

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 short sentences, each carrying distinct information (scope, units, cost), with the core purpose front-loaded. Nothing is redundant with the title or schema.

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?

An output schema exists, so return structure need not be described, and the description fills the remaining gaps (units, cap, billing). Minor gap: 'the 11 listed tenors' is never enumerated, so the agent cannot know which tenors without inspecting the output schema.

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 tool takes zero parameters, so the baseline is 4 and there is nothing for the description to disambiguate. The note that output is capped at the 11 standard tenors gives useful shape to an otherwise argument-free call.

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 and resource: 'Return the current US Treasury curve across 11 standard tenors'. No sibling tool returns curve data, so the resource alone distinguishes it from calculate, get_bonds, get_history, etc.

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?

The word 'current' implies a live snapshot rather than historical series, which weakly separates it from bondterminal_get_history, but no alternative is named and no when-to-use/when-not-to-use condition is given. Usage must be inferred from the resource name.

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