Gutendex

Search Books

search_books

Read-onlyIdempotent

Search for books by title or author name. Returns book IDs, titles, authors, and download counts.

Input Schema

Name	Required	Description	Default
`query`	Yes	Title or author name to search for.

Output Schema

Name	Required	Description	Default
`books`	Yes	List of books matching the search query
`count`	Yes	Total number of books matching the search query

Schema Changelog

Changes observed during successful MCP inspections.

Changed2 schema fields changedMay 24, 2026

addedInput schema / examples

Added value: +[
+  {
+    "query": "Jane Austen"
+  },
+  {
+    "query": "Pride and Prejudice"
+  }
+]

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "books": {
+      "description": "List of books matching the search query",
+      "items": {
+        "properties": {
+          "authors": {
+            "description": "List of book authors",
+            "items": {
+              "properties": {
+                "birth_year": {
+                  "description": "Author birth year or null",
+                  "type": [
+                    "number",
+                    "null"
+                  ]
+                },
+                "death_year": {
+                  "description": "Author death year or null",
+                  "type": [
+                    "number",
+                    "null"
+                  ]
+                },
+                "name": {
+                  "description": "Author name",
+                  "type": "string"
+                }
+              },
+              "required": [
+                "name",
+                "birth_year",
+                "death_year"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "download_count": {
+            "description": "Number of downloads",
+            "type": "number"
+          },
+          "formats": {
+            "additionalProperties": {
+              "type": "string"
+            },
+            "description": "Available download formats and URLs",
+            "type": "object"
+          },
+          "id": {
+            "description": "Project Gutenberg book ID",
+            "type": "number"
+          },
+          "languages": {
+            "description": "Languages the book is available in",
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          "subjects": {
+            "description": "Subject tags for the book",
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          "title": {
+            "description": "Book title",
+            "type": "string"
+          }
+        },
+        "required": [
+          "id",
+          "title",
+          "authors",
+          "languages",
+          "subjects",
+          "download_count",
+          "formats"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "count": {
+      "description": "Total number of books matching the search query",
+      "type": "number"
+    }
+  },
+  "required": [
+    "count",
+    "books"
+  ],
+  "type": "object"
+}

Changed2 schema fields changedMay 12, 2026

removedInput schema / examples

Removed value: -[
-  {
-    "query": "Jane Austen"
-  },
-  {
-    "query": "Pride and Prejudice"
-  }
-]

changedOutput schema / (root)

Previous value: -{
-  "properties": {
-    "books": {
-      "description": "List of books matching the search query",
-      "items": {
-        "properties": {
-          "authors": {
-            "description": "List of book authors",
-            "items": {
-              "properties": {
-                "birth_year": {
-                  "description": "Author birth year or null",
-                  "type": [
-                    "number",
-                    "null"
-                  ]
-                },
-                "death_year": {
-                  "description": "Author death year or null",
-                  "type": [
-                    "number",
-                    "null"
-                  ]
-                },
-                "name": {
-                  "description": "Author name",
-                  "type": "string"
-                }
-              },
-              "required": [
-                "name",
-                "birth_year",
-                "death_year"
-              ],
-              "type": "object"
-            },
-            "type": "array"
-          },
-          "download_count": {
-            "description": "Number of downloads",
-            "type": "number"
-          },
-          "formats": {
-            "additionalProperties": {
-              "type": "string"
-            },
-            "description": "Available download formats and URLs",
-            "type": "object"
-          },
-          "id": {
-            "description": "Project Gutenberg book ID",
-            "type": "number"
-          },
-          "languages": {
-            "description": "Languages the book is available in",
-            "items": {
-              "type": "string"
-            },
-            "type": "array"
-          },
-          "subjects": {
-            "description": "Subject tags for the book",
-            "items": {
-              "type": "string"
-            },
-            "type": "array"
-          },
-          "title": {
-            "description": "Book title",
-            "type": "string"
-          }
-        },
-        "required": [
-          "id",
-          "title",
-          "authors",
-          "languages",
-          "subjects",
-          "download_count",
-          "formats"
-        ],
-        "type": "object"
-      },
-      "type": "array"
-    },
-    "count": {
-      "description": "Total number of books matching the search query",
-      "type": "number"
-    }
-  },
-  "required": [
-    "count",
-    "books"
-  ],
-  "type": "object"
-}New value: +null

Changed1 schema field changedMay 8, 2026

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "books": {
+      "description": "List of books matching the search query",
+      "items": {
+        "properties": {
+          "authors": {
+            "description": "List of book authors",
+            "items": {
+              "properties": {
+                "birth_year": {
+                  "description": "Author birth year or null",
+                  "type": [
+                    "number",
+                    "null"
+                  ]
+                },
+                "death_year": {
+                  "description": "Author death year or null",
+                  "type": [
+                    "number",
+                    "null"
+                  ]
+                },
+                "name": {
+                  "description": "Author name",
+                  "type": "string"
+                }
+              },
+              "required": [
+                "name",
+                "birth_year",
+                "death_year"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          "download_count": {
+            "description": "Number of downloads",
+            "type": "number"
+          },
+          "formats": {
+            "additionalProperties": {
+              "type": "string"
+            },
+            "description": "Available download formats and URLs",
+            "type": "object"
+          },
+          "id": {
+            "description": "Project Gutenberg book ID",
+            "type": "number"
+          },
+          "languages": {
+            "description": "Languages the book is available in",
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          "subjects": {
+            "description": "Subject tags for the book",
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          },
+          "title": {
+            "description": "Book title",
+            "type": "string"
+          }
+        },
+        "required": [
+          "id",
+          "title",
+          "authors",
+          "languages",
+          "subjects",
+          "download_count",
+          "formats"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "count": {
+      "description": "Total number of books matching the search query",
+      "type": "number"
+    }
+  },
+  "required": [
+    "count",
+    "books"
+  ],
+  "type": "object"
+}

Changed1 schema field changedMay 6, 2026

addedInput schema / examples

Added value: +[
+  {
+    "query": "Jane Austen"
+  },
+  {
+    "query": "Pride and Prejudice"
+  }
+]

First observedApr 14, 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, idempotentHint, and non-destructive behavior, lowering the bar. The description adds useful context by listing the exact return fields (book IDs, titles, authors, download counts), which goes beyond the annotations. It does not mention pagination or limits, but the addition of return fields justifies a 4.

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, front-loaded sentence with no unnecessary words. Every phrase adds value, stating the search criteria and return fields compactly.

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 simple search tool with one parameter, an output schema, and strong annotations, the description covers the essential behavioral and return-value context. It does not need to explain pagination or filters given the tool's simplicity and existing structured metadata.

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 the parameter description ('Title or author name to search for') fully matches the tool description. The description adds no additional meaning beyond the schema, so the 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 a specific verb ('Search') and resource ('books'), clearly stating search criteria (title or author) and return fields (book IDs, titles, authors, download counts). This distinguishes it from sibling tools like 'books_by_topic' (topic-based) and 'get_book' (single book retrieval).

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 implies when to use it: when searching by title or author. It provides clear context but does not explicitly name alternative tools or exclusions, 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.

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Search Books

Input Schema

Output Schema

Schema Changelog

TDQS

Glama MCP Gateway

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