inflation_calculatorUS inflation calculator from official CPI-U: what an amount of dollars in one year (or month) is worth in another, from 1913 to now, with cumulative and average annual inflation. Costs $0.003 USDC per call (x402).
| Name | Required | Description | Default |
|---|---|---|---|
| to | No | Year or YYYY-MM, default this year | |
| from | Yes | Year (1913+) or YYYY-MM | |
| amount | No |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint and openWorldHint, and the description adds context they don't carry: the official CPI-U data source, the 1913-to-now coverage window, the two output metrics (cumulative and average annual inflation), and a per-call cost of $0.003 USDC via x402, which is material for an agent deciding to invoke it. It does not cover rate limits or precision/rounding behavior.
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?
A single front-loaded sentence carrying purpose, data source, range, and outputs, followed by one short cost sentence. Dense but every clause earns its place; slightly run-on due to stacked parentheticals.
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 no output schema, the description compensates by naming the returned metrics and data provenance, and it discloses cost, which is essential for an x402 tool. Minor gaps remain: no mention of what happens for invalid ranges (from later than to) or non-US currencies.
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 67%: 'from' and 'to' are documented in the schema, while 'amount' has no description anywhere. The description reinforces the accepted formats ('one year (or month)') and the 1913+ boundary, but adds no token beyond the schema for the undocumented amount parameter, so the baseline of 3 fits.
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+resource (inflation calculator) with precise scope: official CPI-U data, US dollars, one year/month to another, 1913 to now, returning cumulative and average annual inflation. That detail distinguishes it from the nearby sibling inflation_breakdown without needing the schema.
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 implies when it applies ('what an amount of dollars in one year is worth in another') and the cost note signals a paid x402 call, but it never states when to prefer it over siblings like inflation_breakdown or economy, nor any exclusions such as non-US currencies.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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