cross-validated-search

<div align="center"> <h1>Zero-API-Key Web Search</h1> <p><strong>Free web search, browsing & claim verification for AI agents.</strong></p> <p><em>No API keys. No accounts. No limits. 100% free.</em></p>

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What is this?

A single pip install gives your AI agent live web search, full-page reading, and evidence-aware claim verification — all without any API key, account, or paid service.

• Search: Live results from DuckDuckGo (free) + optional SearXNG (self-hosted, free)
• Browse: Extract clean text from any URL, stripping boilerplate automatically
• Verify: Classify claims as supported / contested / likely false with evidence scores
• Report: Generate citation-ready evidence reports with rationale and next steps

Quick start

pip install zero-api-key-web-search

# Search the web
zero-search "Python 3.13 release" --json

# Read a page
zero-browse "https://docs.python.org/3/whatsnew/" --json

# Verify a claim
zero-verify "Python 3.13 is the latest stable release" --deep --json

# Full evidence report
zero-report "Python 3.13 stable release" \
  --claim "Python 3.13 is the latest stable release" --deep --json

Legacy CLI aliases (search-web, browse-page, verify-claim, evidence-report) also work.

Why this over a plain search wrapper?

Feature	Plain search	Zero-API-Key Web Search
Live search results	✅	✅
News / images / videos / books	❌	✅
Region & time filtering	❌	✅
Full-page text extraction	❌	✅
Claim verification with evidence scores	❌	✅
Supporting vs. conflicting evidence	❌	✅
Citation-ready evidence reports	❌	✅
Dual-provider cross-validation	❌	✅
API key required	Often	Never
Cost	Sometimes	Free

MCP server

Works with Claude Code, Cursor, Copilot, and any MCP-compatible agent:

{
  "mcpServers": {
    "zero-api-key-web-search": {
      "command": "zero-mcp"
    }
  }
}

Four tools exposed: search_web, browse_page, verify_claim, evidence_report.

Platform support

Platform	Status	Entry point
CLI	Ready	zero-search, zero-browse, zero-verify, zero-report
MCP	Ready	zero-mcp
Claude Code	Ready	.claude/skills/zero-api-key-web-search/SKILL.md
Gemini	Ready	GEMINI.md + .gemini/SKILL.md
Cursor	Ready	.cursor/rules/zero-api-key-web-search.md
Copilot	Ready	.github/copilot/instructions.md
Codex	Ready	.codex/SKILL.md
Continue	Ready	.continue/skills/zero-api-key-web-search/SKILL.md
Manus	Ready	Root SKILL.md + docs/manus.md
Kiro	Ready	.kiro/steering/zero-api-key-web-search.md
OpenClaw	Ready	zero_api_key_web_search/skills/SKILL.md

How verification works

zero-verify uses the evidence-aware heuristic v3 model:

1. Search for the claim across available providers
2. Score each source on keyword overlap, source quality, freshness
3. Classify as supporting, conflicting, or neutral
4. Optionally fetch top pages for deeper page-aware analysis
5. Render a verdict with confidence and evidence breakdown

Verdict	Meaning
supported	Strong evidence, low conflict
likely_supported	Leans positive, not decisive
contested	Support and conflict both meaningful
likely_false	Conflict strong, support weak
insufficient_evidence	Too weak for any firmer verdict

This is a heuristic evidence classifier, not a proof engine. See docs/trust-model.md for details and limitations.

Free dual-provider setup

Default install uses DuckDuckGo. For stronger cross-validated evidence, add a free self-hosted SearXNG:

./scripts/start-searxng.sh
export ZERO_SEARCH_SEARXNG_URL="http://127.0.0.1:8080"
./scripts/validate-free-path.sh

Or with Docker Compose:

cp .env.searxng.example .env
docker compose -f docker-compose.searxng.yml up -d

Full guide: docs/searxng-self-hosted.md.

Evidence report example

{
  "verdict": "contested",
  "confidence": "MEDIUM",
  "executive_summary": "Evidence is split...",
  "verdict_rationale": ["Source A supports...", "Source B contradicts..."],
  "coverage_warnings": ["Single-provider evidence path."],
  "source_digest": [
    {"title": "...", "url": "...", "classification": "supporting", "evidence_strength": 3}
  ],
  "next_steps": ["Add a second provider for cross-validation."]
}

Architecture

zero_api_key_web_search/
  core.py              # UltimateSearcher — search, verify, report engine
  browse_page.py       # Readability-style page text extraction
  mcp_server.py        # MCP server (4 tools)
  transport.py         # SSL/TLS helpers
  search_web.py        # CLI: zero-search
  browse_page.py       # CLI: zero-browse
  verify_claim.py      # CLI: zero-verify
  evidence_report.py   # CLI: zero-report
  providers/
    base.py            # SearchProvider protocol (sync + async)
    ddgs.py            # DuckDuckGo provider
    searxng.py         # SearXNG provider
  skills/
    SKILL.md           # Bundled OpenClaw skill

Key engineering features:

• Circuit breaker: Trips after 3 consecutive provider failures, auto-resets after 60s
• Async support: asearch() for concurrent provider calls via asyncio.gather
• Structured logging: Configurable logging at search/verify/report entry points
• Readability heuristic: Semantic HTML5 + ARIA roles + text density scoring
• Baseline comparison: Majority-vote and keyword-count baselines in reports
• Sub-claim decomposition: Targeted sub-queries for independent evidence gathering

Installation

pip install zero-api-key-web-search

Python 3.10+ required. No API keys, no accounts, no configuration needed.

Development

pip install -e ".[dev]"
python -m pytest tests/ -x           # 86 tests
ruff check zero_api_key_web_search/ tests/
pyright zero_api_key_web_search/     # 0 errors
coverage report --fail-under=80       # 85% coverage

Verification for ecosystem reviewers

1. zero-report "Python 3.13 stable release" --claim "Python 3.13 is the latest stable release" --deep --json
2. docs/ecosystem-readiness.md
3. docs/gemini-submission-checklist.md
4. docs/trust-model.md

License

MIT License.