Build tiered fallback systems that degrade performance, not availability. Cache layers, API resilience, and automatic failover patterns for platform reliability.
Builds tiered fallback systems that maintain availability when components fail. Claude uses this when implementing cache-first patterns, API resilience, or CI/CD dependency resolution to ensure operations continue through degraded tiers instead of crashing.
/plugin marketplace add adaptive-enforcement-lab/claude-skills/plugin install patterns@ael-skillsThis skill inherits all available tools. When active, it can use any tool Claude has access to.
examples.mdreference.mdscripts/example-1.mermaidscripts/example-10.goscripts/example-11.yamlscripts/example-12.yamlscripts/example-2.textscripts/example-3.yamlscripts/example-4.goscripts/example-5.textscripts/example-6.yamlscripts/example-7.textscripts/example-8.textscripts/example-9.goGraceful degradation is a design principle that ensures systems continue operating when components fail. Rather than crashing or returning errors, the system automatically falls back to slower but working alternatives.
flowchart TD
subgraph request[Request]
A[Operation Requested]
end
subgraph tiers[Fallback Tiers]
T1[Tier 1: Optimal]
T2[Tier 2: Acceptable]
T3[Tier 3: Guaranteed]
end
subgraph result[Result]
Success[Success]
end
A --> T1
T1 -->|Works| Success
T1 -->|Fails| T2
T2 -->|Works| Success
T2 -->|Fails| T3
T3 --> Success
%% Ghostty Hardcore Theme
style A fill:#65d9ef,color:#1b1d1e
style T1 fill:#a7e22e,color:#1b1d1e
style T2 fill:#fd971e,color:#1b1d1e
style T3 fill:#f92572,color:#1b1d1e
style Success fill:#a7e22e,color:#1b1d1e
The key insight: degrade performance, not availability.
From From 5 Seconds to 5 Milliseconds:
Volume Mount → API Call → Rebuild Cache
1-5ms 50ms 5000ms
# Kubernetes volume mount with optional flag
volumes:
- name: cache-volume
configMap:
name: deployment-cache
optional: true # Tier 1 can fail gracefully
See examples.md for detailed code examples.
Artifact Cache → Dependency Cache → Fresh Install
seconds minutes minutes+
See examples.md for detailed code examples.
Primary Endpoint → Secondary Endpoint → Cached Response → Static Fallback
SSO → API Token → Service Account → Anonymous (read-only)
Degrading without logging or alerting means you won't know when Tier 1 is broken.
// Bad: silent fallback
func getData() []byte {
if data, _ := cache.Get(); data != nil {
return data
}
return fetchFromAPI() // No indication we're in degraded mode
}
// Good: observable fallback
func getData() []byte {
if data, err := cache.Get(); err == nil {
metrics.CacheHit()
return data
}
metrics.CacheMiss()
log.Warn("cache miss, falling back to API")
return fetchFromAPI()
}
Every chain needs a final tier that always succeeds.
// Bad: can fail completely
func getConfig() (*Config, error) {
if cfg := cache.Get(); cfg != nil {
return cfg, nil
}
return api.FetchConfig() // What if API is also down?
}
// Good: guaranteed fallback
func getConfig() *Config {
if cfg := cache.Get(); cfg != nil {
return cfg
}
if cfg, err := api.FetchConfig(); err == nil {
return cfg
}
return DefaultConfig() // Always works
}
Using Tier 3 as the happy path defeats the purpose.
# Bad: always does full install
- run: npm ci
- uses: actions/cache/save@v4
with:
path: node_modules/
# Good: cache-first approach
- uses: actions/cache@v4
id: cache
with:
path: node_modules/
key: deps-${{ hashFiles('package-lock.json') }}
- if: steps.cache.outputs.cache-hit != 'true'
run: npm ci
You need to know:
- name: Report cache tier
run: |
if [ "${{ steps.mount-cache.outcome }}" = "success" ]; then
echo "cache_tier=mount" >> metrics.txt
elif [ "${{ steps.api-cache.outcome }}" = "success" ]; then
echo "cache_tier=api" >> metrics.txt
else
echo "cache_tier=rebuild" >> metrics.txt
fi
See reference.md for additional techniques and detailed examples.
These patterns are complementary, not contradictory:
| Scenario | Pattern | Reasoning |
|---|---|---|
| Precondition not met | Fail Fast | Don't waste resources on doomed operations |
| Runtime component fails | Graceful Degradation | Continue with fallback |
| Invalid input | Fail Fast | User error, report immediately |
| Network timeout | Graceful Degradation | Infrastructure issue, retry/fallback |
| Missing required config | Fail Fast | Can't continue safely |
| Cache miss | Graceful Degradation | Expensive path still works |
Decision rule: Fail fast on precondition failures. Degrade gracefully on runtime failures.
Degrading without logging or alerting means you won't know when Tier 1 is broken.
See examples.md for detailed code examples.
Every chain needs a final tier that always succeeds.
See examples.md for detailed code examples.
Using Tier 3 as the happy path defeats the purpose.
See examples.md for detailed code examples.
You need to know:
- name: Report cache tier
run: |
if [ "${{ steps.mount-cache.outcome }}" = "success" ]; then
echo "cache_tier=mount" >> metrics.txt
elif [ "${{ steps.api-cache.outcome }}" = "success" ]; then
echo "cache_tier=api" >> metrics.txt
else
echo "cache_tier=rebuild" >> metrics.txt
fi
See examples.md for code examples.
See reference.md for complete documentation.