Cache Memory

Cache memory provides persistent file storage across workflow runs via GitHub Actions cache with 7-day retention. The compiler automatically configures the cache directory, restore/save operations, and progressive fallback keys at /tmp/gh-aw/cache-memory/ (default) or /tmp/gh-aw/cache-memory-{id}/ (additional caches).

Enabling Cache Memory

---
tools:
  cache-memory: true
---

Stores files at /tmp/gh-aw/cache-memory/ using default key memory-${{ github.workflow }}-${{ github.run_id }}. Use standard file operations to store/retrieve JSON/YAML, text files, or subdirectories.

Advanced Configuration

---
tools:
  cache-memory:
    key: custom-memory-${{ github.workflow }}-${{ github.run_id }}
    retention-days: 30  # 1-90 days, extends access beyond cache expiration
    allowed-extensions: [".json", ".txt", ".md"]  # Restrict file types (default: empty/all files allowed)
---

File Type Restrictions

The allowed-extensions field restricts which file types can be written to cache-memory. By default, all file types are allowed (empty array). When specified, only files with listed extensions can be stored.

---
tools:
  cache-memory:
    allowed-extensions: [".json", ".jsonl", ".txt"]  # Only these extensions allowed
---

If files with disallowed extensions are found, the workflow will report validation failures.

Multiple Configurations

---
tools:
  cache-memory:
    - id: default
      key: memory-default
    - id: session
      key: memory-session-${{ github.run_id }}
    - id: logs
      retention-days: 7
---

Mounts at /tmp/gh-aw/cache-memory/ (default) or /tmp/gh-aw/cache-memory-{id}/. The id determines folder name; key defaults to memory-{id}-${{ github.workflow }}-${{ github.run_id }}.

Merging from Shared Workflows

---
imports:
  - shared/mcp/server-memory.md
tools:
  cache-memory: true
---

Merge rules: Single→Single (local overrides), Single→Multiple (local converts to array), Multiple→Multiple (merge by id, local wins).

Behavior

GitHub Actions cache: 7-day retention, 10GB per repo, LRU eviction. Add retention-days to upload artifacts (1-90 days) for extended access.

Caches accessible across branches with unique per-run keys. Custom keys auto-append -${{ github.run_id }}. Progressive restore splits on dashes: custom-memory-project-v1-${{ github.run_id }} tries custom-memory-project-v1-, custom-memory-project-, custom-memory-, custom-.

Best Practices

Use descriptive file/directory names, hierarchical cache keys (project-${{ github.repository_owner }}-${{ github.workflow }}), and appropriate scope (workflow-specific default or repository/user-wide). Monitor growth within 10GB limit.

Comparison with Repo Memory

Feature	Cache Memory	Repo Memory
Storage	GitHub Actions Cache	Git Branches
Retention	7 days	Unlimited
Size Limit	10GB/repo	Repository limits
Version Control	No	Yes
Performance	Fast	Slower
Best For	Temporary/sessions	Long-term/history

For unlimited retention with version control, see Repo Memory.

Troubleshooting

• Files not persisting: Check cache key consistency and logs for restore/save messages.
• File access issues: Create subdirectories first, verify permissions, use absolute paths.
• Cache size issues: Track growth, clear periodically, or use time-based keys for auto-expiration.

Integrity-Aware Caching

When a workflow uses tools.github.min-integrity, cache-memory automatically applies integrity-level isolation. Cache keys include the workflow’s integrity level and a hash of the guard policy so that changing any policy field forces a cache miss.

The compiler generates git-backed branching steps around the agent. Before the agent runs, it checks out the matching integrity branch and merges down from all higher-integrity branches (higher integrity always wins conflicts). After the agent runs, changes are committed to that branch. The agent itself sees only plain files — the .git/ directory rides along transparently in the Actions cache tarball.

Merge semantics

Run integrity	Sees data written by	Cannot see
merged	merged only	approved, unapproved, none
approved	approved + merged	unapproved, none
unapproved	unapproved + approved + merged	none
none	all levels	—

This prevents a lower-integrity agent from poisoning data that a higher-integrity run would later read.

Note

Existing caches will get a cache miss on first run after upgrading to a version that includes this feature — intentional, as legacy data has no integrity provenance.

Security

Don’t store sensitive data in cache memory. Cache memory follows repository permissions.

Logs access. With threat detection, cache saves only after validation succeeds (restore→modify→upload artifact→validate→save).

Examples

See Grumpy Code Reviewer for tracking PR review history.

Related Documentation

• Repo Memory - Git branch-based persistent storage with unlimited retention
• Frontmatter - Complete frontmatter configuration guide
• Safe Outputs - Output processing and automation
• GitHub Actions Cache Documentation - Official GitHub cache documentation