Azure/azure-sdk-for-python azure-ai-finetuningsessions_1.0.0b1

on GitHub

1.0.0b1 (2026-09-24)

Features Added

• Add the generated InputChunk hierarchy and InputChunkType. Existing ModelInputChunk keyword/mapping calls remain valid and now emit type="text"; image inputs retain their existing serialization and validation.
• Reuse the current 12-member canonical shared FoundryFeaturesOptInKeys, preserving six original member names/values with six canonical additions. The fine-tuning preview header is unchanged.
• Add optional SamplingParams.response_format for compatible sampling providers and the friendly SamplingOperationResult alias for SampleOperationResult.
• Include Loom's maintained read-only SampleOperationResult.prompt_tokens: Optional[int] for backend-reported evidence, counted once per prompt. Accept only exact non-negative integers; missing or invalid evidence is None, with no boolean/float/string coercion or inferred counts. The identical SamplingOperationResult alias and existing constructor keywords/overloads are unchanged.
• Support AZURE_AI_FINETUNING_MAX_CHUNK_BYTES as an import-time positive-integer override for the approximate request chunk-size budget. Unset or invalid values keep the 5,000,000-byte default; invalid values log a warning. Service-side limits are unchanged.
• Add the string-backed TrainingType enum, reusing the REST training-tier definition. Existing string inputs and omission behavior remain supported.
• Initial preview of interactive fine-tuning sessions with synchronous and asynchronous clients.
• Forward-only requests, checkpoint resume and deletion, JSON-valued session metadata, and training-tier selection.
• Multimodal image input, vision/projector LoRA settings, nullable prompt log-probabilities, and per-operation metrics.
• Bounded retries, preserved session identifiers, typed service errors, and operation progress logging.

Breaking Changes

• Require Python 3.10 or later; Python 3.9 is no longer supported.
• Remove AGENTS_OPTIMIZATION_V2_PREVIEW from the historical 13-member enum snapshot to follow its removal from the upstream canonical definition; the six original fine-tuning SDK members remain available.
• Require an explicit lora_config with LoRAConfig.rank in session creation and checkpoint-resume methods, and in CreateSessionRequest. No implicit rank or empty configuration is supplied.
• The distribution is named azure-ai-finetuningsessions and Python imports now use azure.ai.finetuningsessions. Remove older preview installations and update imports/dependency files before installing this build.
• The preview baseline replaces the earlier regenerated-only surface with the established preview API plus explicitly documented contract changes. Callers of earlier raw models, operation methods, or keyword adapters should check the current signatures when migrating.

Bugs Fixed

• Preserve credential redirect protections with the declared minimum Azure Core 1.37.0 as well as current versions; handle the cleanup flag location change in Azure Core 1.38.3.
• Drain async heartbeat tasks before session/client shutdown, including concurrent cancellation; share the sync client's pipeline so custom policies work and all transports close normally.
• Bound creation and sustained-error retry sleeps; tolerate bounded request-store propagation after creation and reject unexpected polling states immediately.
• Reject empty training batches and incomplete sampler identifiers; bound synchronous chunk workers and offload async forward chunking.
• Preserve generic handling for explicit non-batch payload limits and typed errors for malformed capacity retry hints; reject unhandled redirects during deletion.
• Propagate direct-route context headers through default raw-operation pipelines with endpoint scoping and caller overrides; omit response payloads from normal INFO logs.
• Preserve the sync heartbeat thread when shutdown has not completed, validate mapping-form image inputs, and return actual completed Tasks from async multichunk/wave methods as documented.
• Handle nested HTTP 503 error details while preserving flat-response compatibility.
• Map engine_dead polling failures to TrainingEngineError, preserving error codes and diagnostic references without retrying lost engine state.
• Handle non-object error bodies safely, ignore invalid or non-finite retry hints, and validate positional image mappings consistently with keyword inputs.
• Require HTTPS and configured-origin scoping for default API-key authentication, with explicit configured-loopback HTTP opt-in only. Remove SDK-default direct-route headers outside their origin/path scope, including prepopulated defaults, while preserving distinct caller overrides.
• Disable automatic POST transport retries in default sync/async policies, including heartbeats. Explicit retry policies remain caller-owned; this does not guarantee deduplication or change convenience-level recovery decisions.
• Make default raw begin_* pollers use HTTP 200 acceptance and session/request-ID GET polling in both clients, without POST replay or synthetic HTTP 202. Preserve result callbacks, custom polling, no-polling, and strategy-specific continuation behavior.

Other Changes

• Reuse 18 canonical TypeSpec aliases, including ModelInput, while retaining 22 compatibility models and three compatibility unions for intentional Python-only contracts. Correct LoRA, sampling, and training-tier documentation without changing service behavior.
• Move Python-only TypeSpec compatibility definitions to session-finetuning/models-custom-code.tsp, imported only by SDK generation. Retain the existing SDK namespace, public types, and generated type identities; the move does not add these projections to REST.
• Keep the input-chunk migration SDK-first: normalize legacy token-only ModelInput mappings only when type is absent and preserve unknown explicit tags. Production service behavior is unchanged; strict discriminator enforcement and compatibility policy are deferred to public preview (PuPr).
• Refresh TypeSpec provenance after snake_case training-tier member naming and service-grounded identifier minimum lengths; training-tier wire values are unchanged.
• Use the Foundry required-preview operation contract and documented schema defaults with supported Python customization hooks for request query ordering and established convenience behavior.
• Use the repository's shared Python emitter 0.63.8, backend 0.38.0, compiler 1.16.0, and client generator core 0.72.2. Genuine regeneration incorporates the upstream unused-import fix; generated files are not manually patched to pass CI.
• Remove the package-local emitter override. Keep standalone tooling archives and validation records under the package's engineering directory, and verification commands under its scripts directory; standard README and generation guidance remain at the package root.
• Record the unchanged 48-file historical oracle at source commit 485774df502642879fdf3a53777be4a0d95155dc in eng/generation/reference.json. See GENERATION.md for current guidance, exact reviewed contracts, and historical evidence.
• Retain /fine_tuning/sessions routes and established convenience APIs. The earlier use_legacy_routes option is not included in this preview.
• Use AST overload inspection on all supported Python versions rather than importing Python 3.11-only typing.get_overloads; retain the assertions on Python 3.10.
• Correct the spelling pipeline failure on Python's global-namespace keyword in the surface verifier without changing runtime behavior or weakening validation.
• Preserve the separately committed preview baseline and record intentional changes in eng/generation/review-deltas.json. Background heartbeat startup remains unchanged; opt-in-only startup is still deferred.

The current refresh has two matching isolated emissions and a passing public
source-test run. Final test totals and gate outcomes must come from final
validation records; final Loom, installed-wheel, and public CI results are not
yet verified. No commands or builds were run for this documentation-only update.

Historical local validation, before the input-chunk and shared-enum changes:
1,637 SDK tests passed on Python 3.13.14. The
comparison and negative-guard counts, generation method, and limitations are in
GENERATION.md. These results do not validate the final combined changes or claim a new final-wheel run,
validation of the new tests on Python 3.10, remote CI success, or release approval.