Document Similarity

Compare two images or PDFs for visual similarity via the PDFAPIHub cloud API. Documents are uploaded to pdfapihub.com for comparison using feature matching,...

Security Scan

The skill does what it says — it uploads two documents to the PDFAPIHub cloud API to compute visual similarity — and its instructions and required network interaction are consistent with that purpose.

Purpose & Capability

The skill's name, description, SKILL.md and example.json consistently describe uploading two documents to https://pdfapihub.com/api for similarity comparison. One small inconsistency: registry metadata lists no primary credential or required env vars, while skill.json and SKILL.md indicate an API key (CLIENT-API-KEY) is required for requests. This is likely an administrative/metadata omission rather than a functional mismatch.

Instruction Scope

The runtime instructions only describe sending the two files (via URLs, base64 bodies, or multipart) to the PDFAPIHub API and receiving a similarity score. There are no instructions to read local system files, secrets, or unrelated config, nor to transmit data to any endpoint other than pdfapihub.com.

Install Mechanism

This is an instruction-only skill with no install spec and no code files to write to disk, so there is no install-time risk.

Credentials

The service requires an API key sent in the CLIENT-API-KEY header, which is appropriate for this cloud API. However, the skill registry metadata did not list a primary credential or required env var while skill.json marks auth as required — an inconsistency that should be clarified (the skill itself does not attempt to access other unrelated credentials).

Persistence & Privilege

The skill does not request persistent presence (always: false), does not modify other skills or system settings, and has no install-time hooks. Autonomous invocation is enabled by default but is not combined with other concerning privileges.

Assessment

This skill appears internally consistent and simply proxies two documents to PDFAPIHub for comparison. Before using it: (1) Do not upload confidential or regulated documents unless you trust pdfapihub.com and have reviewed their privacy/retention policies (SKILL.md says files are auto-deleted after 30 days). (2) Provide an API key in the CLIENT-API-KEY header when invoking; note the registry metadata omitted a declared primary credential — confirm how your deployment will supply the key (per-request header vs. environment variable). (3) Test with non-sensitive sample files first to verify behavior. (4) If you need offline/local comparisons or do not want third-party uploads, this skill is not appropriate.

What It Does

Compares two documents (images or PDFs) for visual similarity via the PDFAPIHub hosted API. Both documents are uploaded to PDFAPIHub servers where comparison is performed, and a similarity score (0–1) with confidence level is returned.

When to Use

• Check if two documents are visually similar
• Detect duplicates or near-duplicates
• Compare image variations

Comparison Methods

Method	Description
auto	Automatically selects best method (default)
feature_match	OpenCV feature matching
ssim	Structural Similarity Index
phash	Perceptual hashing

Supported Combinations

• image + image
• pdf + pdf
• image + pdf

Required Inputs

Two files via one of:

• url1 + url2 — public URLs
• image1_base64 + image2_base64 — base64-encoded files
• Multipart upload with file1 and file2

Authentication

This skill calls the PDFAPIHub hosted API at https://pdfapihub.com/api. Both documents are uploaded to PDFAPIHub servers for comparison.

Send your API key in the CLIENT-API-KEY header.

Get your free API key at https://pdfapihub.com. Full API documentation is available at https://pdfapihub.com/docs.

Privacy note: Both documents you compare are uploaded to PDFAPIHub's cloud service for processing. Do not send confidential documents unless you trust the service. Files are auto-deleted after 30 days.

Use Cases

• Duplicate Detection — Identify duplicate or near-duplicate documents in a repository
• Brand Consistency — Compare generated documents against approved templates for visual consistency
• QA Testing — Compare rendered PDFs/images before and after code changes for regressions
• Fraud Detection — Compare submitted documents against known genuine samples
• Document Versioning — Quantify visual differences between document revisions
• Container Inspection — Compare shipping container photos for damage assessment

Example Usage

curl -X POST https://pdfapihub.com/api/v1/document/similarity \
  -H "CLIENT-API-KEY: your_api_key" \
  -H "Content-Type: application/json" \
  -d '{
    "url1": "https://pdfapihub.com/sample-document-similarity-1.jpg",
    "url2": "https://pdfapihub.com/sample-document-similarity-2.jpg",
    "method": "auto"
  }'