measure-mcp

fba_data_status

Check which Amazon FBA rules dataset is in force, its effective dates, peak status, surcharges, and verification level before quoting fees or acting on other FBA caveats.

Instructions

Report which FBA rules dataset is in force and how much to trust it. Call this before quoting a fee, or when another fba tool's caveats point here.

date (ISO, default today) is the day to check. Returns dataset_id, as_of date of the data, effective range, the peak window and whether peak or non-peak fees apply on that day, active surcharges, a per-section verification table (official / secondary_cross_checked / secondary / unverified), the list of rows that are verified versus not, unverified_fields, staleness warnings (data older than 90 days or past its review date), source URLs and the 90-day reimbursement window. Fee and tier rows are currently compiled from third-party sources, so treat them as estimates; Amazon's own measurement and fee schedule govern.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`date`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 16, 2026

TDQS

A4.6/5.0

Behavior5/5

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

With no annotations, the description carries the full behavioral burden and does so thoroughly: it discloses data provenance (third-party compiled sources), what 'verified' vs 'unverified' means, staleness thresholds (90 days / past review date), the 90-day reimbursement window, and a direct caution that rows are estimates. This is exactly the failure-mode context an agent needs before quoting fees.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose and the call-site trigger, followed by parameter and return detail. Sentences earn their place, though the long parenthetical enumerations of return fields are dense and could be trimmed given an output schema exists.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter status tool, the description covers purpose, timing, input semantics, provenance caveats, and confidence levels. It even enumerates return fields despite an output schema existing, so nothing an agent needs is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0% and the schema gives no description for `date`, so the description must compensate. It specifies the format (ISO), the default (today), and the meaning ('the day to check'), plus what the date affects (peak vs non-peak fees). Minor gap: it does not clarify behavior if the date lies outside the effective range.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb+resource: reporting which FBA rules dataset is in force and how much to trust it. It is clearly distinguishable from sibling fee/size tools (fba_fee_estimate, fba_size_tier) because it positions itself as the trust/metadata check rather than a calculation.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives an explicit trigger: 'Call this before quoting a fee, or when another fba tool's `caveats` point here.' That is a concrete when-to-use condition tied to sibling tools. There is no explicit when-not guidance or named alternative, 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.