feat(skills): add ctx7 CLI registry-based discovery section §5.5

- New subsection in §5.5: ctx7 skills suggest/install/setup workflow
- Clarifies agentskills.io (spec) vs context7.com/skills (registry)
- Cross-reference note in mcp-servers-ecosystem.md Context7 entry
- Resource evaluation: 2026-03-17-context7-cli.md (score 4/5)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/resource-evaluations/2026-03-17-context7-cli.md

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+# Resource Evaluation: Context7 CLI (ctx7)
+
+**URL**: https://context7.com/docs/clients/cli
+**Date**: 2026-03-17
+**Evaluator**: Claude Sonnet 4.6
+**Score**: 4/5
+
+## Summary
+
+CLI companion to the Context7 MCP server (Upstash). Covers three functions: fetch library docs in terminal, manage skills (install/search/suggest/generate), configure Context7 for Claude Code.
+
+Key commands:
+- `npx ctx7 skills suggest` — auto-detects project deps, recommends matching skills
+- `npx ctx7 skills install owner/repo` — install from any GitHub repository
+- `npx ctx7 setup --claude` — wizard for MCP or CLI+Skills mode configuration
+- `npx ctx7 library [name]` / `ctx7 docs [id] [query]` — doc lookup without browser
+
+## Decision
+
+**Integrated** into `guide/ultimate-guide.md` §5.5 as new subsection "Registry-based Discovery: ctx7 CLI" (~60 lines) and a cross-reference note in `guide/ecosystem/mcp-servers-ecosystem.md` Context7 section.
+
+## Key Finding
+
+The existing workflow (curl/unzip from GitHub) is replaced by `ctx7 skills suggest` + `ctx7 skills install`, which adds dependency-awareness and trust scores. The guide was documenting a 2024 manual workflow for a 2025 ecosystem.
+
+## Fact-Check Note
+
+First WebFetch call hallucinated "Built by Anthropic" for Context7 — this is false. Context7 is an Upstash product (confirmed via mcp-servers-ecosystem.md: `@upstash/context7-mcp`). Corrected before integration.
+
+## Registry Relationship
+
+- `agentskills.io` = open spec (30+ platforms, defined skill format) — guide §5.1
+- `context7.com/skills` = hosted registry of conforming skills with trust scores
+- These are complementary, not competing. Documented in the guide integration.