ferric-fred-mcp

get_series_categories

Read-onlyIdempotent

List the FRED categories that contain a specified series ID. Enter a series ID to see its location in the category tree.

Instructions

List the categories a FRED series belongs to (the reverse of get_category_series): given a series id, where it sits in the category tree.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`series_id`	Yes	The FRED series id, e.g. `GNPCA` or `UNRATE`.

Output Schema

TableJSON Schema

Name	Required	Description	Default
`count`	Yes	The number of categories returned.
`categories`	Yes	The categories the series belongs to.

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.3.6Jul 6, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$defs": {
+    "Category": {
+      "description": "A node in the FRED category tree (the `fred/category` and\n`fred/category/children` endpoints).",
+      "properties": {
+        "id": {
+          "$ref": "#/$defs/CategoryId",
+          "description": "The category's identifier."
+        },
+        "name": {
+          "description": "Human-readable name, e.g. `\"Trade Balance\"`.",
+          "type": "string"
+        },
+        "parent_id": {
+          "$ref": "#/$defs/CategoryId",
+          "default": 0,
+          "description": "The parent category's id. For the root category this is\n[`CategoryId::ROOT`] (`0`), which FRED may also omit entirely."
+        }
+      },
+      "required": [
+        "id",
+        "name",
+        "parent_id"
+      ],
+      "type": "object"
+    },
+    "CategoryId": {
+      "description": "A FRED category identifier — a numeric node in the category tree (the root is\n[`CategoryId::ROOT`], id `0`).\n\nA `Copy` newtype over `u32` so a category id can't be silently swapped for a\nparent id, a count, or an arbitrary number (ADR-0005). `#[serde(transparent)]`\ncarries it on the wire as the bare integer FRED sends.",
+      "format": "uint32",
+      "minimum": 0,
+      "type": "integer"
+    }
+  },
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "properties": {
+    "categories": {
+      "description": "The categories the series belongs to.",
+      "items": {
+        "$ref": "#/$defs/Category"
+      },
+      "type": "array"
+    },
+    "count": {
+      "description": "The number of categories returned.",
+      "format": "uint",
+      "minimum": 0,
+      "type": "integer"
+    }
+  },
+  "required": [
+    "count",
+    "categories"
+  ],
+  "type": "object"
+}

First observedv0.3.2Jul 6, 2026

TDQS

A4.3/5.0

Behavior4/5

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds value beyond annotations by clarifying the tool is a reverse lookup and providing hierarchical context ('where it sits in the category tree'). No contradictions or omissions. Slight deduction because it could mention the output structure explicitly, but output schema reduces need.

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?

The description is a single, well-structured sentence. It starts with the action verb, includes the core purpose, and adds context efficiently. No unnecessary words.

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?

Given the tool has a single parameter, full annotations, an output schema, and a clear description that distinguishes it from siblings, the description is complete. It provides all needed context for an agent to select and invoke correctly.

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 coverage is 100% and the input schema provides a detailed description for series_id with examples. The tool description does not add extra parameter information, but that is acceptable since the schema fully covers it. Baseline of 3 is appropriate.

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?

The description uses the verb 'List' and explicitly states the action: 'list the categories a FRED series belongs to'. It also provides context by noting it's the reverse of get_category_series, clearly differentiating it from siblings. The purpose is specific and unambiguous.

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?

The description gives clear usage context by naming the alternative tool (get_category_series) and explaining the reverse relationship. This helps the agent choose between them. However, it does not explicitly state when not to use this tool or provide exclusion criteria.

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