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

Annotations already establish readOnly, non-destructive, and idempotent behavior. The description adds genuinely useful context beyond the annotations: it mentions the provenance field with source-specific as-of datesassword, explains that it renders as a chart in MCP Apps, and notes the educational-only nature.

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 dense but well structured: core content first, then caveats, provenance, and rendering behavior. It is slightly long due to the enumeration of rates and auctions, but every clause adds information an agent would want before invoking the tool.

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 no-input, read-only information tool, the description covers the data content, sources, provenance, and client-side rendering behavior. There is no output schema to reference, so a brief note about the return shape or data frequency would make it fully complete, but nothing critical is missing.

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?

This tool has zero parametersNotifications, so the schema is trivially complete. The baseline for a no-parameter tool is 4, and the description adds no conflicting or unnecessary parameter information.

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 clearly identifies the resource as the US Treasury par yield curve and enumerates its key components (forwards, NY Fed rates, auctions, AI read). Although it lacks an explicit action verb like 'retrieves' or 'provides', the domain and output are unmistakable and distinct from the general tape analytics siblings.

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 description gives no explicit guidance on when to use this tool versus alternatives like tape_market_pulse or tape_analytics. The 'Educational only' caveat is a limitation, not a selection criterion, so an agent must infer the intended use solely from the resource name and content.

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