Chain Patterns

Overview

Foundation patterns for CC 2.1.71 pipeline skills. This skill is loaded via the skills: frontmatter field — it provides patterns that parent skills follow.

Pattern 1: MCP Detection (ToolSearch Probe)

Run BEFORE any MCP tool call. Probes are parallel and instant.

# FIRST thing in any pipeline skill — all in ONE message:
ToolSearch(query="select:mcp__memory__search_nodes")
ToolSearch(query="select:mcp__context7__resolve-library-id")
ToolSearch(query="select:mcp__sequential-thinking__sequentialthinking")

# Store results for all phases:
Write(".claude/chain/capabilities.json", JSON.stringify({
  "memory": true_or_false,
  "context7": true_or_false,
  "sequential": true_or_false,
  "timestamp": "ISO-8601"
}))

Usage in phases:

# BEFORE any mcp__memory__ call:
if capabilities.memory:
    mcp__memory__search_nodes(query="...")
# else: skip gracefully, no error

Load details: Read("${CLAUDE_SKILL_DIR}/references/mcp-detection.md")

Pattern 2: Handoff Files

Write structured JSON after every major phase. Survives context compaction and rate limits.

Write(".claude/chain/NN-phase-name.json", JSON.stringify({
  "phase": "rca",
  "skill": "fix-issue",
  "timestamp": "ISO-8601",
  "status": "completed",
  "outputs": { ... },           # phase-specific results
  "mcps_used": ["memory"],
  "next_phase": 5
}))

Location: .claude/chain/ — numbered files for ordering, descriptive names for clarity.

Load schema: Read("${CLAUDE_SKILL_DIR}/references/handoff-schema.md")

Pattern 3: Checkpoint-Resume

Read state at skill start. If found, skip completed phases.

# FIRST instruction after MCP probe:
Read(".claude/chain/state.json")

# If exists and matches current skill:
#   → Read last handoff file
#   → Skip to current_phase
#   → Tell user: "Resuming from Phase N"

# If not exists:
Write(".claude/chain/state.json", JSON.stringify({
  "skill": "fix-issue",
  "started": "ISO-8601",
  "current_phase": 1,
  "completed_phases": [],
  "capabilities": { ... }
}))

# After each major phase:
# Update state.json with new current_phase and append to completed_phases

Load protocol: Read("${CLAUDE_SKILL_DIR}/references/checkpoint-resume.md")

Pattern 4: Worktree-Isolated Agents

Use isolation: "worktree" when spawning agents that WRITE files in parallel.

# Agents editing different files in parallel:
Agent(
  subagent_type="backend-system-architect",
  prompt="Implement backend for: {feature}...",
  isolation="worktree",       # own copy of repo
  run_in_background=true
)

When to use worktree: Agents with Write/Edit tools running in parallel. When NOT to use: Read-only agents (brainstorm, assessment, review).

Load details: Read("${CLAUDE_SKILL_DIR}/references/worktree-agent-pattern.md")

Pattern 5: CronCreate Monitoring

Schedule post-completion health checks that survive session end.

# Guard: Skip cron in headless/CI (CLAUDE_CODE_DISABLE_CRON)
# if env CLAUDE_CODE_DISABLE_CRON is set, run a single check instead
CronCreate(
  schedule="*/5 * * * *",
  prompt="Check CI status for PR #{number}:
    Run: gh pr checks {number} --repo {repo}
    All pass → CronDelete this job, report success.
    Any fail → alert with failure details."
)

Load patterns: Read("${CLAUDE_SKILL_DIR}/references/cron-monitoring.md")

Rules

Rule	Impact	Key Pattern
`rules/probe-before-use.md`	HIGH	Always ToolSearch before MCP calls
`rules/handoff-after-phase.md`	HIGH	Write handoff JSON after every major phase
`rules/checkpoint-on-gate.md`	MEDIUM	Update state.json at every user gate

References

Load on demand with Read("${CLAUDE_SKILL_DIR}/references/<file>"):

File	Content
`mcp-detection.md`	ToolSearch probe pattern + capability map
`handoff-schema.md`	JSON schema for `.claude/chain/*.json`
`checkpoint-resume.md`	state.json schema + resume protocol
`worktree-agent-pattern.md`	`isolation: "worktree"` usage guide
`cron-monitoring.md`	CronCreate patterns for post-task health
`tier-fallbacks.md`	T1/T2/T3 graceful degradation

Related Skills

ork:implement — Full-power feature implementation (primary consumer)
ork:fix-issue — Issue debugging and resolution pipeline
ork:verify — Post-implementation verification
ork:brainstorm — Design exploration pipeline

chain-patterns