notarius/docs/internal/llm.md

# LLM Runtime Internals

`internal/framework/llm` is Notarius’s provider-independent structured
completion boundary. It adapts framework requests to PromptKit, bounds
provider calls, assembles registered prompt and schema assets, records selected
profiles, and redacts provider errors. The architectural boundary is defined in
[Architecture](../policy/architecture.md#llm-boundary); profile sources,
credentials, and concurrency settings belong in
[Configuration](../config.md#promptkit-profiles) and
[Configuration](../config.md#concurrency-output-cache-and-debug).

## Structured Completion Boundary

Modules and LLM-backed validators depend only on
`contracts.StructuredLLMClient`. A completion request supplies a prompt ID and
version, optional profile and session IDs, named input material, variables, and
a caller-owned decode target. The successful response returns the validated raw
structured bytes together with non-secret provider, model, profile, and token
metadata.

The caller owns the domain behavior: it chooses the prompt, prepares inputs,
selects the private response schema, and interprets the decoded result. The
adapter does not own source evidence, artifact conversion, normalization, or
durable schemas. Those responsibilities remain with the module and its
[integration contract](../integrations/).

`PromptKitClient` validates the request target and prompt identity, maps each
named material to a PromptKit inline artifact while preserving its origin URI,
maps the request session to the existing `session_id` prompt variable, forwards
profile selection, then prepares and runs the prompt. PromptKit v0.1.0 has no
direct request-level session field. The adapter returns PromptKit’s validated
raw bytes rather than re-encoding the decoded target. An empty optional
material is represented as one space so its named input is retained by
PromptKit.

An empty request profile lets the prompt select its configured default. The CLI
prepares every explicitly selected binding profile before a run begins, so a
missing explicit profile fails before stage execution. Calls record the profile
actually selected by PromptKit; the recorder deduplicates non-secret profile
identity, provider, and model values for manifest use. Successful completion
responses and recorded profile manifests identify the adapter provider as
`promptkit`.

Before execution, the adapter also contributes a non-secret checkpoint
fingerprint for the effective PromptKit profile source. It combines the
identity of PromptKit's compiled-in profile catalog with a deterministic digest
of every YAML profile in the configured profile directory, or of the configured
profile file. The fingerprint contains neither profile content nor source
paths. It covers both explicit binding profiles and prompt-selected defaults,
so changing a model or other profile setting cannot reuse checkpoints created
under the prior profile source. This cache identity is independent of durable
profile provenance: run manifests continue to list only profiles actually
observed during LLM calls.

## Shared Provider-Call Limit

Production construction creates one PromptKit client and wraps it in one
scheduled client. The scheduler has a fixed, positive permit limit, serves
queued calls in FIFO order, and removes a queued call when its context is
cancelled. A granted permit is released exactly once on every completion path.

The scheduled wrapper surrounds every `CompleteStructured` call, so concurrent
lanes, pipeline retries, and LLM-backed validators share the same provider-call
ceiling. This ceiling is independent of pipeline worker concurrency; changing
worker counts cannot exceed the configured LLM limit. The configuration field
and its effective default are owned by
[Configuration](../config.md#concurrency-output-cache-and-debug).

## Prompt And Schema Assets

An `AssetRegistry` collects prompt and schema filesystems from production module
families. It flattens registered roots into the PromptKit filesystems and
rejects invalid roots, unreadable assets, duplicate paths, and missing prompt
or schema files during preparation. The framework’s `promptfs` helper combines
module-owned prompt files with reusable domain fragments without making the
framework depend on D&D content.

Each LLM-backed module owns its prompt declaration, package-specific assets,
and private response schema. Shared D&D wording is owned by the D&D shared
asset package; the detailed D&D conventions are in
[D&D Module Internals](dnd.md). The mounted prompt assets used by a module also
determine its prompt fingerprint. Schema loaders validate JSON, attach identity
and digest metadata, make defensive copies, and expose diagnostics without raw
schema bytes.

Private response schemas validate a model transport envelope. They are not the
durable artifact schema and should not be documented as an external wire
contract. Durable formats and compatibility rules remain in the
[integration contracts](../integrations/).

## Prompt Maintenance And Backend Caching

Prompt message order and shared asset bytes are runtime behavior. Backend cache
reuse depends on identical preceding roles, rendered bytes, and cache-control
metadata—not merely equivalent meaning. Keep reusable shared assets
byte-identical and preserve each prompt’s declared ordering and cache controls
when editing it.

For sibling prompts that can reuse the same source material, order universal
shared context first, request source material next, and module-specific
suffixes last. Put a cache boundary at a reusable prefix that is useful to the
backend. Redundant intermediate cache boundaries do not extend that reusable
prefix and add no value.

Prompt-family owners may choose a different sequence when their inputs and
reuse pattern differ. The D&D family’s extraction, scene-chunking, and NPC
normalization policies are maintained in [D&D Module Internals](dnd.md#prompt-construction).
Do not add tests that enforce prompt prose; prompt tests should verify the
meaningful input placement and cache controls of the prompt being changed.

## Validation, Repair, And Retries

PromptKit performs prompt rendering, provider execution, and the prompt’s
structured-output validation. The adapter reports an empty result, validation
failure, empty structured body, or decode failure as
`ErrInvalidStructuredOutput`, while retaining the returned raw bytes and debug
material when they exist. Provider failures remain operational errors rather
than output-validation failures.

Prompt-declared repair is executed within PromptKit’s structured-output flow.
The current production D&D prompt manifests set repair attempts to zero. That
setting does not replace pipeline retry behavior: a binding’s configured retry
count reruns its stage attempt after an error or rejection, and an exhausted
rejection is a recorded output rather than a provider error. The pipeline owns
attempt lifecycle, validation chains, and retry diagnostics; see
[Pipeline Internals](pipeline.md#validation-retries-and-output) and the
[binding reference](../config.md#module-bindings-and-validators).

## Timeout Ownership

The caller context remains the outer cancellation authority. PromptKit applies
a positive effective generation timeout as an inner request deadline; an
explicit zero disables only that generation deadline. The HTTP client timeout
is a separate transport-wide cap. Notarius forwards the caller context and
does not install another timeout wrapper around PromptKit.

The selected PromptKit profile owns generation settings. Notarius binding
retries remain outside the adapter and repeat the complete module operation
and validation chain. PromptKit v0.1.0 does not add a provider retry loop.
Operator-facing behavior is summarized in
[Operations](../operations.md#operational-limits), and the pinned upstream
contract is identified in
[PromptKit Integration](../integrations/pkg-promptkit.md).

## Observability And Redaction

When debug recording is enabled, the pipeline decorates the shared client. The
wrapper records prepared prompt and response material, timing, selected profile
and model, and call identifiers in the run’s debug bundle, including material
available from a failed structured completion. For a successful completion, a
debug-write failure is surfaced; when the completion already failed, its call
error remains the result. Debug-bundle location, retention, and handling are
operational concerns documented in [Operations](../operations.md#debug-bundles).

Run manifests receive selected profile summaries and component identities, not
prompt, schema, source, reference, or response content. Provider error text is
wrapped with prompt context and bearer credentials are redacted before it
crosses the runtime boundary. Known-secret redaction is available to other
runtime collaborators; it does not make prompt or response contents safe for
general logging.

## Failure Boundaries

- Construction fails for missing asset registries, mutually exclusive profile
  sources, invalid asset registration, or a non-positive scheduler limit.
- Preparation failures, unavailable explicit profiles, provider failures, and
  context cancellation propagate to the calling stage with context.
- Malformed or schema-invalid provider output is classified separately as
  invalid structured output so the module or pipeline can apply its own retry
  and rejection policy.
- Domain semantic checks, evidence decisions, and deterministic normalization
  run outside the provider adapter.

## Focused Verification

Read the LLM adapter, scheduler, asset registry, schema loader, and redaction
tests when changing this boundary. Prompt changes also require the owning
module’s asset tests, and retry or debug changes require focused pipeline or
CLI coverage. The focused runtime and D&D checks are:

~~~sh
go test ./internal/framework/llm/... ./internal/modules/dnd/...
~~~