The public API surface

In one line: Nine always-present modules, two gated modules, and 148 re-exported items at the crate root, grouped by the feature that gates them
You need: Nothing; this page mirrors src/lib.rs
Read this if: You are looking for the import path of a type, or which feature makes it exist

src/lib.rs opens with #![forbid(unsafe_code)], so no unsafe block compiles anywhere in the crate. A build with no provider feature stops at a compile_error!; see The feature matrix.

Modules

Module	Visibility	Gate	Holds
`types`	`pub`	none	the unified wire types shared by every provider adapter
`error`	`pub`	none	`CucaError` and `PluginError`
`request`	`pub`	none	the normalized request and response contracts
`session`	`pub`	none	the append-only session audit-trail model
`sse`	`pub`	none	the SSE stream parser
`plugin`	`pub`	none	the `CucaPlugin` and `SessionStorePlugin` traits
`plugins`	`pub`	none	plugin implementations, one gated submodule per `plugin-*` feature
`services`	`pub`	none	service implementations, one gated submodule per `service-*` feature
`client`	`pub`	none	the builder, the client and the plugin-instrumented stream
`export`	`pub`	`plugin-memory` or `service-prompt-cache`	the versioned `cuca-export` envelope
`cost_otel`	`pub`	`plugin-cost` and `plugin-telemetry`	the cost ledger to OpenTelemetry bridge
`provider`	`pub(crate)`	none	the provider adapters; not part of the public surface
`canonical`	`pub(crate)`	`plugin-session-log` or `service-prompt-cache`	canonical JSON encoding for storage records and digest input
`tokenize`	`pub(crate)`	`plugin-memory` or `plugin-cost`	tiktoken encoder resolution

Ungated re-exports

Available in every build that compiles. There are 17.

Group	Items
Client	`CucaClient`, `CucaClientBuilder`, `ResponseHandle`
Errors	`CucaError`, `PluginError`
Request and response	`AgentResponseStream`, `PromptCacheBreakpoint`, `PromptCacheDirective`, `PromptCacheUsage`, `ThinkingConfig`, `ThinkingEffort`, `ThinkingParams`, `TokenUsage`, `UnifiedRequest`, `UnifiedResponse`
Session	`SessionEvent`, `SessionRecord`

PromptCacheBreakpoint, PromptCacheDirective and PromptCacheUsage are ungated although service-prompt-cache is gated. They are fields of UnifiedRequest and UnifiedResponse, so they exist wherever those do. TokenUsage is ungated for the same reason.

Items outside the crate root

Path	Items
`cuca::types`	`MessageContentBlock`, `MessageRole`, `ProviderEndpoint`, `ToolDefinition`, `UnifiedMessage`
`cuca::sse`	`SseEvent`, `SseStreamParser`
`cuca::plugin`	`CucaPlugin`, `SessionStorePlugin`
`cuca::services::orchestrator`	`PoolTurnExecutor`, which is `pub` but not re-exported at the root

LlamaCppConfig and OAuthPkceConfig live in the pub(crate) provider module and have no public path.

Feature-gated re-exports

There are 131, in 21 groups.

Gate	Items
`provider-local`	`DownloadProgress`, `DownloadProgressCallback`, `DraftStats`, `DrafterSource`, `GpuAdapter`, `LocalCapabilities`, `LocalDevice`, `LocalModel`, `LocalModelConfig`, `ModelPreset`, `ModelSource`, `SamplingConfig`
`plugin-cost`	`CostConfig`, `CostEntry`, `CostObserver`, `CostPlugin`, `CostUsage`, `ModelRates`, `PricingResolver`, `PricingTable`, `UnpricedModelPolicy`
`plugin-guardrails`	`JsonGuardrailPlugin`
`plugin-hitl`	`ApprovalChannel`, `ApprovalDecision`, `ApprovalRequest`, `HitlPlugin`, `OneshotApprovalChannel`, `Risk`
`plugin-mcp`	`McpPlugin`, `McpTransport`
`plugin-memory`	`Budget`, `CompactionStrategy`, `CompressionAction`, `CompressionReport`, `ContextUsage`, `ContextUsageObserver`, `ContextWindowResolver`, `GRAPH_RENDER_MARKER`, `GraphContextConfig`, `GraphDirection`, `GraphImportReport`, `GraphNode`, `GraphRelationship`, `GraphSnapshot`, `MemoryConfig`, `MemoryGraph`, `MemoryPlugin`, `MergePolicy`, `MergeReport`, `Summarizer`, `VectorStore`
`plugin-redaction`	`Redacted`, `RedactionConfig`, `RedactionPlugin`, `RedactionRule`
`plugin-sandbox`	`SandboxConfig`, `SandboxPlugin`, `SandboxResult`
`plugin-session-log`	`FileBackend`, `InMemoryBackend`, `SessionBackend`, `SessionLogPlugin`
`plugin-skills`	`Skill`, `SkillsConfig`, `SkillsPlugin`
`plugin-subagent`	`SubagentPlugin`, `SubagentResult`, `SubagentRunner`, `SubagentSpec`, `WorktreeConfig`
`plugin-telemetry`	`OpenTelemetryPlugin`
`plugin-web-search`	`SearchResult`, `WebSearchConfig`, `WebSearchPlugin`, `WebSearchProvider`
`service-entity-extraction`	`CandidateEntity`, `CandidateRelationship`, `EntityExtractionCandidate`, `EntityExtractionModel`, `EntityExtractionReport`, `EntityExtractionSchema`, `EntityExtractor`, `EntityReference`, `EntityTable`, `PropertyColumn`, `PropertyType`, `RelationshipTable`
`service-prompt-cache`	`PromptCache`, `PromptCacheConfig`, `PromptCacheEntry`, `PromptCacheError`, `PromptCacheImportReport`, `PromptCacheSnapshot`
`service-rate-limit`	`RateLimitConfig`, `RateLimitError`, `RateLimitObserver`, `RateLimitPermit`, `RateLimitUsage`, `RateLimiter`
`service-replay`	`ReplayCompletion`, `ReplayConfig`, `ReplayNote`, `ReplayTrajectory`, `ReplayTurn`, `ReplayUsage`, `SessionReplay`
`service-speculative`	`ClientPool`, `Complexity`, `ComplexityEvaluator`, `DraftValidator`, `JsonToolDraftValidator`, `ModelOrchestrator`, `SwappableModelPair`, `TurnExecutor`
`service-vector-store`	`Embedder`, `InMemoryVectorStore`, `RECALL_RENDER_MARKER`, `RecallInjection`, `RetrievalReport`, `RetrievedTurn`, `VectorStoreConfig`, `VectorStoreError`, `VectorStoreUsage`
`plugin-memory` or `service-prompt-cache`	`CUCA_EXPORT_FORMAT`, `CUCA_EXPORT_VERSION`, `CucaExport`, `CucaExportError`, `CucaImportReport`, `GraphExportSection`, `PromptCacheExportSection`
`plugin-cost` and `plugin-telemetry`	`OtelCostObserver`

Export envelope constants

Constant	Type	Value
`CUCA_EXPORT_FORMAT`	`&str`	`cuca-export`
`CUCA_EXPORT_VERSION`	`u32`	`1`

Client surface

CucaClientBuilder methods, in declaration order:

Method	Gate
`new`	none
`with_llamacpp_config`	`provider-llamacpp`
`with_local_model`	`provider-local`
`with_provider`	none
`with_base_url`	none
`with_api_key`	none
`with_bearer_token`	`provider-anthropic`
`with_anthropic_oauth`	`provider-anthropic`
`register_plugin`	none
`with_orchestrator`	`service-speculative`
`with_prompt_cache_config`	`service-prompt-cache`
`with_prompt_cache_service`	`service-prompt-cache`
`build`	none

with_provider is required. build fails with CucaError::Config without it.
With ProviderEndpoint::Local, build also fails with CucaError::Config unless with_local_model attached a model.
with_bearer_token and with_api_key are mutually exclusive at dispatch time. When both are set, the bearer token wins.
with_prompt_cache_service takes precedence over with_prompt_cache_config. A validation error in the config surfaces from build.
with_base_url and with_api_key configure this client, not the tier clients of a ModelOrchestrator.

CucaClient methods, in declaration order:

Method	Gate
`builder`	none
`selected_provider`	none
`base_url`	none
`api_key`	none
`bearer_token`	`provider-anthropic`
`oauth_config`	`provider-anthropic`
`llamacpp_config`	`provider-llamacpp`
`local_model`	`provider-local`
`orchestrator`	`service-speculative`
`prompt_cache`	`service-prompt-cache`
`prompt_cache_snapshot`	`service-prompt-cache`
`replace_prompt_cache_snapshot`	`service-prompt-cache`
`http_client`	any of the seven HTTP `provider-*` features
`plugins`	none
`generate_stream`	none
`generate_stream_with_response`	none

generate_stream_with_response returns the stream and a ResponseHandle. After the stream yields None, ResponseHandle::take returns the aggregated UnifiedResponse of that call.

The re-export contract is tested

tests/public_exports.rs imports from cuca by name and constructs the types it names, so a removed or renamed re-export fails compilation. Its own gate is any(provider-openai, provider-llamacpp). Its nested modules are gated on service-prompt-cache, service-rate-limit, plugin-redaction, plugin-memory, plugin-cost, the combination of cost and telemetry, either of memory or prompt cache, service-replay and service-vector-store.