Simplify Audita's backend capacity requirements

docs/roadmap/audita-feature-requests.md

@@ -102,26 +102,36 @@ carry generated output, validation findings, and partial execution observations.
 
 Promptkit need not decide Audita's recovery or correction-acceptance policy.
 
-## 4. Aggregate and Workload Capacity Controls
+## 4. Simple Per-Backend Capacity Limits
 
-**Priority: Evaluate after the execution boundary is established.** Audita currently
-needs to reason about total LLM concurrency and separate proposal/validation work,
-which are not equivalent to per-backend limits.
+**Priority: Adoption requirement, largely supported by existing facilities.**
+Audita needs only two protections:
 
-A useful extension would let a consumer impose an overall concurrent-generation
-ceiling alongside backend limits. If the consumer need remains after redesign,
-independently named workload budgets could distinguish proposal from validation
-work without introducing Audita-specific concepts into Promptkit.
+- For a local backend with a hard simultaneous-query limit, keep combined Audita
+  traffic within its assigned capacity. For example, a DGX Spark serving
+  gemma-4-31b-it may allow four simultaneous queries.
+- For a paid API backend, use a reasonable finite concurrency cap so a large
+  transcript or pipeline cannot accidentally launch dozens or thousands of
+  simultaneous billable calls.
 
-The desired outcome is predictable bounded provider activity across initial calls,
-retries, and repair calls, with cancellation-aware waiting and understandable
-capacity rejection. Delayed retries should not unnecessarily prevent unrelated
-eligible work from progressing. Consumers need clear scope and interaction rules
-for all selected limits.
+Proposal and validation calls targeting the same backend should share its limit.
+The protection must cover initial calls, transient retries, and content-repair
+calls. Audita does not need separate proposal/validation budgets, named workload
+limits, or an additional aggregate ceiling across backends.
 
-This is not a request to reproduce Audita's scheduler or introduce a general task
-scheduler. Determine whether existing controls and application orchestration are
-sufficient before expanding the public capacity model.
+Promptkit's existing engine-local, per-backend capacity controls are the intended
+foundation. Audita should select finite limits for the backends it uses; adoption
+must not accidentally leave paid endpoints on an unlimited path. Exact defaults
+remain to be selected. No new fine-grained scheduling feature is requested.
+
+Verify the documented capacity scope in the consumer example, especially as retries
+are added. An engine-local limit does not coordinate other processes or independent
+clients using the same service; a shared local backend must have capacity allocated
+accordingly or enforced at the service boundary. Cross-process coordination is not
+an upstream feature request here.
+
+Concurrency limits bound simultaneous activity, not total token usage or spending
+across a long run. A monetary budget or rate-limiting system is not requested.
 
 ## 5. Representative Consumer Example
 
@@ -154,9 +164,10 @@ This proposal does not change existing releases or their licenses.
 ## Suggested Evaluation Order and Scope
 
 Evaluate retries, failure classification, and execution observations together, then
-use the representative consumer example to assess readiness. Consider additional
-capacity controls only after that exercise establishes a concrete remaining need.
-Resolve licensing before selecting a release for Audita's migration.
+use the representative consumer example to assess readiness and verify shared
+per-backend limits. Existing capacity controls should suffice unless that exercise
+reveals a concrete gap. Resolve licensing before selecting a release for Audita's
+migration.
 
 Existing facilities for embedded sources, application-owned profiles, prepared
 execution, JSON-schema validation, and request-scoped credentials are useful