# Session- and auth-bound task context cache

Key and lifecycle-manage in-process task-context caches by session id and auth generation so concurrent sessions and mid-session auth replace cannot leak or reuse stale context.

Exact reference: {"kind":"skill_version","skill_id":"skl_wCKU3ytdp9mfmqZocBWzrA","version_id":"skv_UV9bEefUdxFGk1DSLYlZhA"}

Applicability: []

# Session- and auth-bound task context cache

## When to use
Use when an agent plugin caches task context before a system-message transform, multiple root or child sessions share one process, and authorization may be revoked or replaced while that process and root session stay alive.

## Steps
1. Key every entry as (sessionId, authGeneration). Carry sessionId in request scope such as AsyncLocalStorage. Resolve authGeneration from the live authorization handle for that session auth lineage, not from a module-level current pointer and not from ALS-cached generation alone.
2. Default-isolate child sessions. If inheritance is required, copy-on-create a snapshot into the child key; never share a mutable object with the parent. Maintain a parent-to-child or auth-lineage index so invalidation reaches all tied keys.
3. On write commit and on inject or read, require entry.authGeneration equals live.authGeneration. Missing or mismatched means empty or default. No parent, sibling, last-writer, or prior-generation fallback.
4. On revoke or replace, in one critical section: bump generation, delete or tombstone older lineage entries, then publish the new credential only if live.authGeneration still equals the bumped value. Reject cache writes whose bound generation is not live at commit time.
5. Treat injected context as prompt data only. Every outbound network or tool call must present a capability bound to the current generation; mismatch fails closed. Cancel work that will take another hop; do not assume already-gated single-shot I/O is recalled.
6. Bound memory: cap entry count, bytes per entry, and total bytes; prefer delete-on-bump and session dispose; use LRU plus TTL for orphans; store slim summaries.

## Limits
- Does not stop prompt text already injected into an in-flight model turn before a bump.
- Cannot recall bytes already on the wire; re-check live generation before applying response side effects.
- Support for this guidance is reasoned analysis and independent design review, not executed tests.

## Failure prevented
Prevents cross-session context injection and same-session auth-rotate races where stale or poisoned cache entries authorize network activity or reappear under a replacement credential.

## Supporting basis and limitations

Derived from reasoned design analysis in the cited conversation covering session isolation, composite auth-generation keys, bump-first invalidation, and network fail-closed checks, plus independent adversarial review corrections: generation-bind cache writes, resolve generation from the live auth handle, atomic bump-clear-publish with compare-and-set, and an explicit child or lineage invalidation index. No repository inspection and no executed tests were performed.

## Change and rationale

Create a focused skill for session- and auth-generation-bound task-context caches in shared-process agent plugins.

Shared-process plugins commonly leak via global current-context pointers and survive auth rotate when caches are session-keyed only. Binding writes, reads, and network capabilities to a live auth generation with compare-and-set publish closes those gaps.