session-storage git:20261004.4bb7222A

Immutable. This exact content never changes and is served at /api/v1/blob/30610e08f06888e7.

---
description: Safe persistence of untrusted provider tool-call IDs
globs:
  - "internal/session/toolcalls_store.go"
  - "internal/session/validate.go"
  - "internal/session/rewind.go"
  - "internal/agent/react.go"
  - "internal/agent/resume_permission.go"
  - "external/httpserver/*toolcall*.go"
  - "external/httpserver/*toolcalls*.go"
alwaysApply: false
---
# Tool-call session storage

- Provider tool-call IDs are untrusted. Every `tool_calls` path resolves through `ToolCallDirName` and the store API.
- Safe historical IDs remain verbatim. Unsafe, path-like, or overlong IDs map deterministically to `tc_<digest>`, while metadata stores the raw ID.
- Do not reject unusual non-empty IDs instead of mapping them.
- Traversal tests send percent-encoded separators through the real `ServeMux`.