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

Annotations already declare readOnlyHint=true, and the description adds useful context: data source (FRED PSAVERT), update frequency (monthly), and that it returns trend, confidence, saving_rate_pct, 3-month change, and top drivers. It does not contradict annotations. Some behavioral details (like the Gold tier requirement for history) are left to the schema, but the description still adds meaningful context.

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 sentences with no filler. The first sentence packs the core functionality and methodology, the second gives explicit use cases, and the third states update frequency. Every sentence earns its place, and the description is well front-loaded.

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?

The description covers what the tool does, its methodology, output fields, update frequency, and use cases. It does not mention the optional history feature (days parameter), but that is fully specified in the schema. Given the tool's simplicity and the schema's completeness, the description is fairly complete, though it could have briefly noted the history option.

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 only parameter (days) is fully documented in the schema with a clear description, giving 100% schema coverage. Per the rubric, the baseline is 3 because the description does not need to repeat parameter details. The description adds no extra parameter semantics, but the schema does the job.

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 states the tool returns a 0-100 US consumer savings-rate stress index, with specific methodology (FRED PSAVERT, inverted, z-scored vs trailing 36-month window) and a threshold interpretation (>50 = below-average saving). This is a specific verb+resource that distinguishes it from any generic sibling tools.

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?

Explicit when-to-use guidance is provided: 'Call when the user asks about consumer savings drawdown, household financial cushion, spending sustainability, or recession stress, or when timing consumer-credit underwriting, lending limits, or debt-to-income cutoffs.' However, it does not mention alternatives or when not to use this tool, so it falls short of a 5.

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