Primary Sources

fred_series

Read-onlyIdempotent

Fetch observations for a St. Louis Fed FRED economic series (requires FRED_API_KEY). Returns dated observations, newest first. Use for US and international economic time series (rates, CPI, GDP); use world_bank_indicator for cross-country development data. Free key required.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`limit`	No	Max observations, default 24
`seriesId`	Yes	FRED series id, e.g. FEDFUNDS, DGS10, CPIAUCSL

Output Schema

TableJSON Schema

Name	Required	Description
`data`	Yes	Source payload; fields vary per tool
`source`	Yes	Human-readable upstream source name
`retrievedAt`	Yes	ISO-8601 timestamp of retrieval

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedOct 3, 2026

addedInput schema / properties / limit / description
```
Added value: +"Max observations, default 24"
```

changedInput schema / properties / seriesId / description

Previous value: -"e.g. FEDFUNDS, DGS10, CPIAUCSL"New value: +"FRED series id, e.g. FEDFUNDS, DGS10, CPIAUCSL"

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "data": {
+      "description": "Source payload; fields vary per tool",
+      "type": "object"
+    },
+    "retrievedAt": {
+      "description": "ISO-8601 timestamp of retrieval",
+      "type": "string"
+    },
+    "source": {
+      "description": "Human-readable upstream source name",
+      "type": "string"
+    }
+  },
+  "required": [
+    "source",
+    "retrievedAt",
+    "data"
+  ],
+  "type": "object"
+}

First observedOct 3, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare readOnly, idempotent, open-world, non-destructive behavior. The description adds genuinely useful context beyond them: the FRED_API_KEY requirement and that observations are returned newest first, which is a real behavioral trait. It stops short of discussing rate limits or error behavior.

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

Conciseness5/5

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

Three short sentences, front-loaded with the core action and return format, followed by routing and the auth prerequisite. Every sentence earns its place with no filler.

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?

With an output schema present and rich annotations, the description only needs to add the auth requirement, ordering, and sibling routing — all of which it does. Nothing an agent needs to invoke this correctly is missing.

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

Parameters3/5

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

Schema description coverage is 100% and both parameters (seriesId with examples, limit with default) are documented in the schema itself. The description adds no parameter-level meaning, so the baseline of 3 applies.

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 (Fetch) and resource (observations for a St. Louis Fed FRED economic series), and names the scope of the data. It explicitly contrasts with world_bank_indicator, letting an agent distinguish it from a sibling without opening the schema.

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 clear usage context ('US and international economic time series (rates, CPI, GDP)') and an explicit alternative with its selection condition (world_bank_indicator for cross-country development data). It does not address other overlapping siblings like dbnomics_series or ecb_series, so routing is clear but not exhaustive.

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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