tools-only MCP Tool Usage Guide
Guidelines for selecting the right MCP tool based on research needs.
Tool Fidelity Levels
| Level | Description | Use Case |
|---|---|---|
| High | Verbatim, authoritative content | Implementation details, API specs |
| Medium | Formatted markdown with code | Documentation, examples |
| Low | Summarized, may omit details | Scoping, overviews |
Tool Selection Matrix
WebFetch (Built-in)
Fidelity: Low (Summarized)
Best For:
- Initial scoping of documentation structure
- Finding what documentation exists
- High-level overviews of tools/libraries
Never Use For:
- Implementation details
- Code examples or file structures
- API specifications
- Anything requiring verbatim accuracy
Why: WebFetch summarizes content and may omit or hallucinate technical details.
mcpRef* Tools
Fidelity: High (Detailed)
Available Tools:
mcp__Ref__ref_search_documentation- Search for documentationmcp__Ref__ref_read_url- Read specific URL content
Best For:
- Official documentation
- API references
- Technical specifications
- Authoritative source content
When to Use: Always prefer Ref for primary documentation sources.
mcpexa* Tools
Fidelity: Medium (Markdown)
Available Tools:
mcp__exa__web_search_exa- Search the web for contentmcp__exa__get_code_context_exa- Extract code patterns from URLs
Best For:
- Code examples and snippets
- Tutorial content
- Implementation patterns
- Community documentation
When to Use: For code-heavy content or when Ref doesn't have the content indexed.
Research Strategy
Phase 1: Discovery (Low Fidelity OK)
Use WebFetch to:
- Find official documentation site
- Understand documentation structure
- Identify key sections to research
Phase 2: Deep Research (High Fidelity Required)
Use Ref and Exa to:
- Read authoritative documentation
- Extract code examples
- Gather implementation details
Phase 3: Validation
Cross-reference multiple sources:
- Official docs (Ref) - primary authority
- Code examples (Exa) - implementation validation
- GitHub repos - real-world usage patterns
Tool Availability Check
MCP tools are dynamically available based on server configuration. Before using, check if the tool exists in your current session's <functions> list.
Fallback Strategy:
If MCP tools unavailable:
- Use WebFetch for initial discovery
- Use WebSearch for finding specific content
- Clone repositories locally and use Read tool for code analysis
Citation Requirements
All research must include source attribution:
According to the official documentation (https://example.com/docs, accessed 2026-02-01), ...
Include:
- Source URL
- Access date
- Section/page if applicable