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
The only action item is updating the version matrix and doctor skill from
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.
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
OrchestKit impact: None — grep confirms zero references to
/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
Symptoms: CC hangs during/after
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
Wasted tokens: Every hook injecting system reminders on SessionStart was doing it twice per resume, inflating context.
--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
Before: Each no-op hook added ~20 tokens of empty reminder boilerplate per turn.
After: No-op hooks produce zero output.
<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).
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 |
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
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.
SessionStart Double-Fire on Resume
Bug: When a user ran
OrchestKit hooks affected (~15):
Impact: Double initialization, double context injection, wasted tokens on every resume.
--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
No-Op System Reminder Injection
Bug: JSON hooks returning empty/no-op responses still injected a
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.
<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.