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osint_isbn_validator

Read-only

Validate ISBN-10 and ISBN-13 numbers by recomputing check digits, converting between formats, and checking prefix groups. Accepts batch input with per-ISBN results and aggregate statistics.

Instructions

ISBN Validator (ISBN-10 / ISBN-13). Validate one or more book ISBNs by recomputing the check digit for ISBN-10 (mod-11, X allowed) and ISBN-13 (EAN-13 mod-10, 978/979 prefix), and report format, the registration group/language, ISBN-10<->13 conversion, and optional step-by-step check-digit math. Accepts a batch and returns per-ISBN results plus aggregate statistics. Use this for book ISBNs; use osint_ean_upc_validator for general EAN/UPC retail barcodes, osint_barcode_scanner to decode a barcode from an image, and osint_barcode_generator to render one. Pure local arithmetic: read-only, non-destructive, no remote book-metadata lookup or network call, offline-capable, rate-limited (CAPTCHA may be required). Each result embeds the validation timestamp, so responses are not byte-identical across calls. Returns each ISBN's validity, type, analysis, conversion, calculation, and warnings.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`isbns`	Yes	ISBN strings to validate. Hyphens and spaces are stripped; each must clean to 10 or 13 digits. Non-string entries are ignored.
`options`	No	Optional flags toggling extra output (camelCase or snake_case keys accepted).

Output Schema

TableJSON Schema

Name	Required	Description
`success`	No	Whether the request was processed.
`results`	No	One entry per validatable input ISBN.
`statistics`	No	Batch totals across all results.

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedv0.5.1Jun 3, 2026

changedInput schema / additionalProperties
```
Previous value: -trueNew value: +false
```

addedInput schema / properties

Added value: +{
+  "isbns": {
+    "description": "ISBN strings to validate. Hyphens and spaces are stripped; each must clean to 10 or 13 digits. Non-string entries are ignored.",
+    "examples": [
+      [
+        "9780306406157",
+        "0306406152"
+      ]
+    ],
+    "items": {
+      "type": "string"
+    },
+    "minItems": 1,
+    "type": "array"
+  },
+  "options": {
+    "additionalProperties": false,
+    "description": "Optional flags toggling extra output (camelCase or snake_case keys accepted).",
+    "properties": {
+      "addHyphenation": {
+        "default": false,
+        "description": "Add a hyphenated ISBN-13 to the conversion block.",
+        "type": "boolean"
+      },
+      "includeFormatConversion": {
+        "default": true,
+        "description": "Include ISBN-10<->ISBN-13 conversion and barcode in each result.",
+        "type": "boolean"
+      },
+      "showCheckDigitCalculation": {
+        "default": false,
+        "description": "Include the weighted-sum formula, expected, and actual check digit.",
+        "type": "boolean"
+      }
+    },
+    "type": "object"
+  }
+}

addedInput schema / required
```
Added value: +[
+  "isbns"
+]
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "properties": {
+    "results": {
+      "description": "One entry per validatable input ISBN.",
+      "items": {
+        "properties": {
+          "analysis": {
+            "description": "Present when valid; check digit, EAN prefix, and registration group.",
+            "properties": {
+              "check_digit": {
+                "description": "The check digit character.",
+                "type": "string"
+              },
+              "check_digit_valid": {
+                "description": "Whether the check digit recomputes correctly.",
+                "type": "boolean"
+              },
+              "clean_isbn": {
+                "description": "ISBN with separators removed.",
+                "type": "string"
+              },
+              "ean_prefix": {
+                "description": "ISBN-13 only: 978 or 979.",
+                "type": "string"
+              },
+              "group_identifier": {
+                "description": "Registration group digits.",
+                "type": "string"
+              },
+              "group_name": {
+                "description": "Language/region for the group.",
+                "type": "string"
+              }
+            },
+            "type": "object"
+          },
+          "calculation": {
+            "additionalProperties": {
+              "type": "string"
+            },
+            "description": "Check-digit steps when showCheckDigitCalculation is set.",
+            "type": "object"
+          },
+          "conversion": {
+            "additionalProperties": {
+              "type": "string"
+            },
+            "description": "ISBN-10/ISBN-13/barcode forms (and hyphenated if requested).",
+            "type": "object"
+          },
+          "input": {
+            "description": "The original ISBN string as received.",
+            "type": "string"
+          },
+          "timestamp": {
+            "description": "Unix epoch seconds when validated.",
+            "type": "integer"
+          },
+          "type": {
+            "description": "Detected type: isbn-10, isbn-13, or isbn-unknown.",
+            "type": [
+              "string",
+              "null"
+            ]
+          },
+          "valid": {
+            "description": "Whether the check digit and format are valid.",
+            "type": "boolean"
+          },
+          "warnings": {
+            "description": "Format errors or deprecation notices.",
+            "items": {
+              "type": "string"
+            },
+            "type": "array"
+          }
+        },
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "statistics": {
+      "description": "Batch totals across all results.",
+      "properties": {
+        "invalid": {
+          "description": "Count of invalid ISBNs.",
+          "type": "integer"
+        },
+        "success_rate": {
+          "description": "Percent valid (0-100, two decimals).",
+          "type": "number"
+        },
+        "total": {
+          "description": "Number of results.",
+          "type": "integer"
+        },
+        "valid": {
+          "description": "Count of valid ISBNs.",
+          "type": "integer"
+        }
+      },
+      "type": "object"
+    },
+    "success": {
+      "description": "Whether the request was processed.",
+      "type": "boolean"
+    }
+  },
+  "type": "object"
+}

First observedv0.1.0May 31, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Goes beyond readOnlyHint=true and destructiveHint=false annotations by detailing pure local arithmetic, no network call, offline-capable, rate-limited, CAPTCHA possibility, and timestamp embedding for non-identical responses. No contradiction with annotations.

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?

Well-structured, front-loaded with core function, and each sentence adds value. Slightly long but not wasteful; could be trimmed slightly for conciseness.

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?

Covers purpose, usage guidelines, behavioral traits, output description (per-ISBN results with aggregate statistics), and optional features. Given complexity and existing schema/annotations, description is fully complete for agent invocation.

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%, so baseline is 3. Description adds context (e.g., step-by-step math for showCheckDigitCalculation) but mostly reiterates schema info. Adequate but not exceptional.

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 clearly states it validates ISBN-10 and ISBN-13 by recomputing check digits, reporting format, registration group/language, and conversion. It explicitly distinguishes from sibling tools (osint_ean_upc_validator, osint_barcode_scanner, osint_barcode_generator) with clear when-to-use guidance.

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

Usage Guidelines5/5

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

Explicitly states 'Use this for book ISBNs' and provides alternatives for general EAN/UPC barcodes. Also clarifies batch acceptance, offline capability, and rate-limiting, giving clear context for appropriate use.

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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