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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered without the description's help. The description adds only that the data is "official" and includes percentiles and repo volume, without disclosing data freshness/lag, rate limits, or response shape. Adequate but with clear gaps, given the low bar set by the annotations.

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?

It is a single front-loaded sentence that leads with verb and resource, with no repetition. The "(#1 in MCP Registry)" parenthetical is unearned promotional text, a minor blemish on an otherwise tight definition.

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?

This is a simple read-only tool with one optional parameter, existing annotations, and no output schema, so the description needn't explain return values. It names the source institution and the metric families returned, which is enough for correct invocation; only freshness and data-range specifics are 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?

Schema coverage is 100% and the sole parameter's description ("Number of recent daily SOFR observations (default 5)") already fully documents it. The description contributes the word "daily," reinforcing the observation cadence but adding no syntax or ordering details 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 uses a specific verb ("Query") and names the exact resource: Federal Reserve Bank of New York official SOFR benchmark rates, plus the included data types (percentiles, daily repo volume). An agent can immediately tell what data domain this covers; the only shortfall is that it doesn't explicitly contrast itself with any of the sibling tools, though the siblings are mostly unrelated domains.

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 tool versus alternatives, no stated prerequisites, and no exclusions. The parenthetical "(#1 in MCP Registry)" is marketing copy rather than a usage signal, so an agent gets no help deciding between this and other data sources.

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