# CC 2.1.73 Upgrade Explorer

OrchestKit v7.3.3 — Interactive upgrade impact analysis
Current: CC >= 2.1.72 → Target: CC >= 2.1.73 89 skills · 31 agents · 99 hooks
Upgrade Overview
CC 2.1.73 is a stability release focused on bug fixes. No new APIs, tools, or slash commands. The upgrade is low-risk with high reward — it fixes 3 bugs that silently affect OrchestKit users.
0
New APIs
1
Deprecation
3
Bug Fixes
1
Behavior Change
▲
Bottom Line
Verdict: Upgrade recommended.
No OrchestKit source edits needed — OrchestKit has no `/output-style` references (the only deprecation). The 3 bug fixes directly benefit OrchestKit's 89 skills, 99 hooks, and users pulling updates via `git pull`.
The only action item is updating the version matrix and doctor skill from `>= 2.1.72` to `>= 2.1.73`.
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Cost Impact
Opus 4.6 is now the default on Bedrock/Vertex/Foundry. OrchestKit's 6 opus-tier agents will use this model automatically on cloud providers. This may affect token costs for enterprise users.
What's New in CC 2.1.73
5 changes from 2.1.72 → 2.1.73. Click cards for details.
!
/output-style deprecated → use /config
Deprecation
The `/output-style` slash command is deprecated in favor of the unified `/config` command.
OrchestKit impact: None — grep confirms zero references to `/output-style` across all 89 skills and docs.
No action needed
✓
Skill-file deadlock fix on git pull
High
Fixed a deadlock triggered by `git pull` in repos with large `.claude/skills/` directories. OrchestKit has 89 skills — this bug was a real-world issue for every user pulling plugin updates.
Symptoms: CC hangs during/after `git pull` when OrchestKit plugin is installed.
Auto-fixed by CC upgrade Was affecting users silently
✓
SessionStart hooks double-fire on resume — fixed
High
SessionStart hooks were firing twice on `--resume` and `--continue`. OrchestKit has ~15 SessionStart hooks across lifecycle, setup, and prompt categories — all were doubling their initialization work.
Wasted tokens: Every hook injecting system reminders on SessionStart was doing it twice per resume, inflating context.
Auto-fixed by CC upgrade Token waste on every resume
✓
JSON hooks no-op system reminder injection — fixed
Medium
JSON-type hooks were injecting empty `<system-reminder>` tags every turn even when returning no content. With 99 hooks, this was a silent context budget drain.
Before: Each no-op hook added ~20 tokens of empty reminder boilerplate per turn.
After: No-op hooks produce zero output.
Auto-fixed by CC upgrade ~2K tokens/turn saved
◎
Opus 4.6 default on Bedrock/Vertex/Foundry
Info
The default Opus model on cloud providers (AWS Bedrock, Google Vertex, Azure Foundry) is now Opus 4.6. OrchestKit's 6 opus-tier agents will become more capable — and potentially more expensive — for enterprise cloud users.
Direct API / anthropic.com users are unaffected (already on Opus 4.6).
Communicate to enterprise users
Impact Matrix
How each 2.1.73 change maps to OrchestKit components.

Change | Skills (89) | Agents (31) | Hooks (99) | Action
--- | --- | --- | --- | ---
/output-style deprecated | Clean | Clean | Clean | None
Skill-file deadlock fix | All 89 benefit | — | — | CC upgrade only
SessionStart double-fire | — | — | ~15 hooks affected | CC upgrade only
No-op reminder injection | — | — | All 99 hooks | CC upgrade only
Opus 4.6 default (cloud) | — | 6 opus agents | — | Document for users

Σ
Net Impact Summary
Source code changes required: 0
Documentation updates: 2 (version matrix + CHANGELOG)
Token savings per session: ~2K tokens/turn from no-op fix + double-fire fix on resume
Stability improvement: No more deadlocks on git pull for 89-skill plugin
Risk level: Minimal — no breaking changes affect OrchestKit
Opus-Tier Agents
These 6 agents use `model: opus`. On Bedrock/Vertex/Foundry, CC 2.1.73 upgrades them to Opus 4.6 automatically.
security-auditor
model: opus
Vulnerability scanning, OWASP Top 10, dependency audits
workflow-architect
model: opus
LangGraph pipelines, supervisor-worker patterns, RAG orchestration
security-layer-auditor
model: opus
Defense-in-depth across 8 security layers
event-driven-architect
model: opus
Event sourcing, CQRS, Kafka, outbox pattern
ai-safety-auditor
model: opus
Red teaming, prompt injection, jailbreak testing
system-design-reviewer
model: opus
Scale, data, security, UX, coherence review
Note: The remaining 25 agents use `model: sonnet` or inherit from the parent session — unaffected by this change.
Hook Bug Fixes
Two fixes that silently affected OrchestKit's 99 hooks before 2.1.73.
1
SessionStart Double-Fire on Resume
Bug: When a user ran `--resume` or `--continue`, all SessionStart hooks fired twice.
OrchestKit hooks affected (~15):
`session-tracking`, `session-env-setup`, `type-error-indexer`, `unified-dispatcher`, `sync-session-dispatcher`, `session-handoff-injector`, `pattern-sync-pull`, `prefill-guard`, `mcp-health-check`, `stale-team-cleanup`, `dependency-version-check`, `setup-check`, and more.
Impact: Double initialization, double context injection, wasted tokens on every resume.
Fixed in CC 2.1.73
2
No-Op System Reminder Injection
Bug: JSON hooks returning empty/no-op responses still injected a `<system-reminder>` wrapper into the conversation.
Scale: 99 hooks × ~20 tokens each = up to ~2K wasted tokens per turn.
Context budget: This was silently eating into the context window, leaving less room for actual skill content, agent reasoning, and user conversation.
Fixed in CC 2.1.73 ~2K tokens/turn recovered
Upgrade Checklist
Interactive checklist — click items to mark as done. Progress is tracked locally.
0 / 8 completed

- Update version-compatibility.md with 2.1.73 features Add 5 new rows to the feature matrix
- Add "Full++++" compatibility level for >= 2.1.73 Deadlock fix, SessionStart fix, no-op fix, Opus 4.6 default
- Update CLAUDE.md minimum CC version to >= 2.1.73 After verifying all fixes are beneficial
- Update identity.json claude_code_version constraint .claude/context/identity.json line 51
- Add CHANGELOG entry for version bump Document the CC minimum version change and why
- Run full test suite after changes npm test — all suites must pass
- Document Opus 4.6 cloud provider impact Note for enterprise users about potential cost changes
- npm run build && verify plugins/ output Rebuild plugins after any src/ changes

Migration Plan
Recommended order for the CC 2.1.73 upgrade.
Phase 0: Research (Done)
Analyzed CC 2.1.73 changelog. Confirmed 5 changes, 0 breaking for OrchestKit.
Phase 1: Impact Assessment (Done)
Scanned 89 skills, 31 agents, 99 hooks. No /output-style refs found. 6 opus agents identified.
Phase 2: Update Version Matrix
Add 2.1.73 features to `version-compatibility.md`. Add "Full++++" support level. Update doctor skill output format.
Phase 3: Bump Minimum Version
Update `CLAUDE.md`, `identity.json`, and `version-compatibility.md` overview from `>= 2.1.72` to `>= 2.1.73`.
Phase 4: Build + Test
`npm run build && npm test` — verify no regressions. Check `plugins/` diff is expected.
Phase 5: Release
Bump to v7.3.4. Add CHANGELOG entry documenting the version bump and bug fix benefits. Create PR targeting `main`.