us-open-stats-mcp

Get Cpi

get_cpi

Fetch a BLS Consumer Price Index point by series ID to get normalized U.S. inflation data as a small JSON snapshot.

Instructions

Return a BLS CPI series point.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "get_cpi"
  }
}

Input Schema

Name	Required	Description	Default
`series_id`	No		CUSR0000SA0

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 28, 2026

TDQS

C2.4/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full behavioral burden, and it discloses almost nothing. It does not state whether an API key is needed, whether the call is rate-limited, what units or seasonal adjustment apply, or the freshness/frequency of the data.

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

Conciseness3/5

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

The single sentence is front-loaded and wastes no words, but at this length it is under-specified rather than genuinely concise. It leaves the reader with no more routing or parameter information than the tool name alone.

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

Completeness3/5

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

An output schema exists, so return values need not be described, which lightens the burden. Still, for a data-retrieval tool with an undocumented, defaulted series_id and a close sibling in get_fred_series, the description omits routing and parameter context the agent needs.

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

Parameters2/5

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

Schema description coverage is 0% and the single parameter series_id has no description, so the description must compensate — it does not. It never explains the meaning of series_id, valid BLS series formats, or what the default value CUSR0000SA0 represents.

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

Purpose3/5

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

States a concrete verb and resource ("Return a BLS CPI series point") and names the data source (BLS), so the agent knows it fetches CPI data. However, it does not distinguish this from siblings that overlap heavily, notably get_fred_series, which can also serve economic time series. "Point" is also ambiguous about whether one observation or a series is returned.

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

Usage Guidelines2/5

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

No when-to-use guidance is given. It never mentions when to prefer this over get_fred_series (which also covers CPI), nor whether series_id should be customized or left at default. The agent must infer routing purely from the tool name.

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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