c3-skill-marketplace

C3: Architecture That Agents Can Read

C3 turns your codebase into something an LLM can navigate. A single .c3/ directory holds architecture docs in a SQLite database — every component, every cross-cutting pattern, every decision, queryable and enforceable.

One Claude Code plugin. One /c3 command. The agent figures out the rest.

claude plugin install lagz0ne/c3-skill

Then: /c3 onboard this project

Why

Architecture docs rot because nobody enforces them. C3 fixes this by making the docs machine-writable and machine-verifiable:

• LLMs read them before touching code — c3x lookup src/auth/login.ts tells the agent which component owns the file, which refs govern it, what rules apply
• Writes are validated — every content update passes through schema enforcement. Missing a required section? Rejected with a hint
• One database, not scattered files — entities, content node trees, relationships, code-map, version history, and changelog in a single c3.db. Full-text search. Graph traversal. Impact analysis
• Every element is trackable — headings, paragraphs, table rows, list items each have a unique ID and SHA256 hash. Entity-level merkle for O(1) change detection. Full version history with pruning

What You Get

Seven operations, one entry point

Say this	C3 does this
/c3 adopt this project	onboard — discovers your architecture through conversation, scaffolds .c3/
/c3 where is auth?	query — full-text search, graph traversal, traces relationships
/c3 add rate limiting	change — ADR-first: impact analysis → decision record → execute → validate
/c3 create a ref for error handling	ref — cross-cutting pattern with Choice/Why/How sections and cite wiring
/c3 add a rule for structured logging	rule — enforceable standard with golden example and anti-patterns
/c3 audit the docs	audit — 10-phase validation: structural → semantic → drift → compliance
/c3 what breaks if I change payments?	sweep — transitive impact across the entity graph

The c3x CLI

A Go binary bundled inside the plugin. No separate install — the skill carries its own binary for every platform (linux/darwin x amd64/arm64).

For agents: The /c3 skill handles invocation automatically via bash <skill-dir>/bin/c3x.sh. Never run bare c3x — always go through /c3. The examples below use c3x as shorthand for readability.

Read/Write cycle:

c3x read c3-101                          # entity content rendered from node tree
c3x read c3-101 --section Goal           # just one section
c3x read c3-101 --json                   # structured JSON

echo "New goal." | c3x write c3-101 --section "Goal"   # section update
cat updated.md | c3x write c3-101                       # full replace (validates + versions)

Search and navigate:

c3x query "authentication"               # full-text search with ranking
c3x lookup src/auth/login.ts             # file → component + refs + rules
c3x impact ref-jwt                       # what breaks if this changes?
c3x graph c3-1 --format mermaid          # visual subgraph

Manage entities:

c3x add component auth --container c3-1 --goal "JWT auth" --json
# → {"id":"c3-101","type":"component","sections":["Goal","Dependencies",...]}

c3x wire c3-101 ref-jwt ref-error-handling   # batch wire multiple targets
c3x set c3-101 --section "Goal" "Handle JWT authentication"
c3x set c3-101 codemap "src/auth/**,src/auth.go"   # set code-map patterns
c3x set c3-101 codemap "src/new/**" --append        # add a pattern

# Batch update (fields + sections + codemap in one call):
echo '{"fields":{"goal":"X"},"codemap":["src/**"]}' | c3x set ref-jwt --stdin

c3x delete ref-obsolete --dry-run

Track changes:

c3x diff                                 # what changed since last commit
c3x diff --mark abc123                   # stamp changelog with commit hash
c3x check                               # validate everything
c3x coverage                            # code-map completeness stats

Content database:

c3x nodes c3-101                         # tree of all nodes with IDs + hashes
c3x nodes c3-101 --json                  # JSON output
c3x hash c3-101                          # root merkle hash
c3x hash c3-101 --recompute             # verify hash integrity
c3x versions c3-101                      # version history
c3x version c3-101 3                     # content at version 3
c3x prune c3-101 --keep 10             # prune old versions

Full command list: c3x --help

Schema enforcement

Every entity type has required sections. The CLI enforces them on write: