zeph-core 0.19.0

// SPDX-FileCopyrightText: 2026 Andrei G <bug-ops>
// SPDX-License-Identifier: MIT OR Apache-2.0

use std::path::PathBuf;
use std::sync::Arc;

use parking_lot::RwLock;

use tokio::sync::{Notify, mpsc, watch};
use zeph_llm::any::AnyProvider;
use zeph_llm::provider::LlmProvider;

use super::Agent;
use super::session_config::{AgentSessionConfig, CONTEXT_BUDGET_RESERVE_RATIO};
use crate::agent::state::ProviderConfigSnapshot;
use crate::channel::Channel;
use crate::config::{
    CompressionConfig, LearningConfig, ProviderEntry, SecurityConfig, StoreRoutingConfig,
    TimeoutConfig,
};
use crate::config_watcher::ConfigEvent;
use crate::context::ContextBudget;
use crate::cost::CostTracker;
use crate::instructions::{InstructionEvent, InstructionReloadState};
use crate::metrics::MetricsSnapshot;
use zeph_memory::semantic::SemanticMemory;
use zeph_skills::watcher::SkillEvent;

/// Errors that can occur during agent construction.
///
/// Returned by [`Agent::build`] when required configuration is missing.
#[derive(Debug, thiserror::Error)]
pub enum BuildError {
    /// No LLM provider configured. Set at least one via `with_*_provider` methods or
    /// pass a provider pool via `with_provider_pool`.
    #[error("no LLM provider configured (set via with_*_provider or with_provider_pool)")]
    MissingProviders,
}

impl<C: Channel> Agent<C> {
    /// Validate the agent configuration and return `self` if all required fields are present.
    ///
    /// Call this as the final step in any agent construction chain to catch misconfiguration
    /// early. Production bootstrap code should propagate the error with `?`; test helpers
    /// may use `.build().unwrap()`.
    ///
    /// # Errors
    ///
    /// Returns [`BuildError::MissingProviders`] when no provider pool was configured and the
    /// model name has not been set via `apply_session_config` (the agent cannot make LLM calls).
    ///
    /// # Examples
    ///
    /// ```ignore
    /// let agent = Agent::new(provider, channel, registry, None, 5, executor)
    ///     .apply_session_config(session_cfg)
    ///     .build()?;
    /// ```
    pub fn build(self) -> Result<Self, BuildError> {
        // The primary provider is always set via Agent::new, but if provider_pool is empty
        // *and* model_name is also empty, the agent was constructed without any valid provider
        // configuration — likely a programming error (e.g. Agent::new called but
        // apply_session_config was never called to set the model name).
        if self.providers.provider_pool.is_empty() && self.runtime.model_name.is_empty() {
            return Err(BuildError::MissingProviders);
        }
        Ok(self)
    }

    // ---- Memory Core ----

    /// Configure the semantic memory store, conversation tracking, and recall parameters.
    ///
    /// All five parameters are required together — they form the persistent-memory contract
    /// that the context assembly and summarization pipelines depend on.
    #[must_use]
    pub fn with_memory(
        mut self,
        memory: Arc<SemanticMemory>,
        conversation_id: zeph_memory::ConversationId,
        history_limit: u32,
        recall_limit: usize,
        summarization_threshold: usize,
    ) -> Self {
        self.memory_state.persistence.memory = Some(memory);
        self.memory_state.persistence.conversation_id = Some(conversation_id);
        self.memory_state.persistence.history_limit = history_limit;
        self.memory_state.persistence.recall_limit = recall_limit;
        self.memory_state.compaction.summarization_threshold = summarization_threshold;
        self.update_metrics(|m| {
            m.qdrant_available = false;
            m.sqlite_conversation_id = Some(conversation_id);
        });
        self
    }

    /// Configure autosave behaviour for assistant messages.
    #[must_use]
    pub fn with_autosave_config(mut self, autosave_assistant: bool, min_length: usize) -> Self {
        self.memory_state.persistence.autosave_assistant = autosave_assistant;
        self.memory_state.persistence.autosave_min_length = min_length;
        self
    }

    /// Set the maximum number of tool-call messages retained in the context window
    /// before older ones are truncated.
    #[must_use]
    pub fn with_tool_call_cutoff(mut self, cutoff: usize) -> Self {
        self.memory_state.persistence.tool_call_cutoff = cutoff;
        self
    }

    /// Enable or disable structured (JSON) summarization of conversation history.
    #[must_use]
    pub fn with_structured_summaries(mut self, enabled: bool) -> Self {
        self.memory_state.compaction.structured_summaries = enabled;
        self
    }

    // ---- Memory Formatting ----

    /// Configure memory formatting: compression guidelines, digest, and context strategy.
    #[must_use]
    pub fn with_memory_formatting_config(
        mut self,
        compression_guidelines: zeph_memory::CompressionGuidelinesConfig,
        digest: crate::config::DigestConfig,
        context_strategy: crate::config::ContextStrategy,
        crossover_turn_threshold: u32,
    ) -> Self {
        self.memory_state.compaction.compression_guidelines_config = compression_guidelines;
        self.memory_state.compaction.digest_config = digest;
        self.memory_state.compaction.context_strategy = context_strategy;
        self.memory_state.compaction.crossover_turn_threshold = crossover_turn_threshold;
        self
    }

    /// Set the document indexing configuration for `MagicDocs` and RAG.
    #[must_use]
    pub fn with_document_config(mut self, config: crate::config::DocumentConfig) -> Self {
        self.memory_state.extraction.document_config = config;
        self
    }

    /// Configure trajectory and category memory settings together.
    #[must_use]
    pub fn with_trajectory_and_category_config(
        mut self,
        trajectory: crate::config::TrajectoryConfig,
        category: crate::config::CategoryConfig,
    ) -> Self {
        self.memory_state.extraction.trajectory_config = trajectory;
        self.memory_state.extraction.category_config = category;
        self
    }

    // ---- Memory Subsystems ----

    /// Configure knowledge-graph extraction and the RPE router.
    ///
    /// When `config.rpe.enabled` is `true`, an `RpeRouter` is initialised and stored in the
    /// memory state. Emits a WARN-level log when graph extraction is enabled, because extracted
    /// entities are stored without PII redaction (pre-1.0 MVP limitation — see R-IMP-03).
    #[must_use]
    pub fn with_graph_config(mut self, config: crate::config::GraphConfig) -> Self {
        // Delegates to MemoryExtractionState::apply_graph_config which handles the RPE router
        // initialization and emits the R-IMP-03 PII warning.
        self.memory_state.extraction.apply_graph_config(config);
        self
    }

    /// Start the `TiMem` tree consolidation background loop and store the handle.
    ///
    /// Call after memory and tree configuration have been applied so that both the `SQLite`
    /// store and config are available. The loop runs until the agent cancel token fires.
    /// The handle is kept in the memory state and is aborted when the agent is dropped.
    ///
    /// No-op if tree consolidation is disabled in the config or memory has not been set.
    #[must_use]
    pub fn with_tree_consolidation_loop(mut self, provider: zeph_llm::any::AnyProvider) -> Self {
        let cfg = &self.memory_state.subsystems.tree_config;
        if !cfg.enabled {
            return self;
        }
        let Some(ref memory) = self.memory_state.persistence.memory else {
            return self;
        };
        let sqlite = std::sync::Arc::new(memory.sqlite().clone());
        let tree_cfg = zeph_memory::TreeConsolidationConfig {
            enabled: cfg.enabled,
            sweep_interval_secs: cfg.sweep_interval_secs,
            batch_size: cfg.batch_size,
            similarity_threshold: cfg.similarity_threshold,
            max_level: cfg.max_level,
            min_cluster_size: cfg.min_cluster_size,
        };
        let cancel = self.lifecycle.cancel_token.clone();
        let handle = zeph_memory::start_tree_consolidation_loop(sqlite, provider, tree_cfg, cancel);
        self.memory_state.subsystems.tree_consolidation_handle = Some(handle);
        self
    }

    // ---- Shutdown Summary ----

    /// Configure the shutdown summary: whether to produce one, message count bounds, and timeout.
    #[must_use]
    pub fn with_shutdown_summary_config(
        mut self,
        enabled: bool,
        min_messages: usize,
        max_messages: usize,
        timeout_secs: u64,
    ) -> Self {
        self.memory_state.compaction.shutdown_summary = enabled;
        self.memory_state.compaction.shutdown_summary_min_messages = min_messages;
        self.memory_state.compaction.shutdown_summary_max_messages = max_messages;
        self.memory_state.compaction.shutdown_summary_timeout_secs = timeout_secs;
        self
    }

    // ---- Skills ----

    /// Configure skill hot-reload: watch paths and the event receiver.
    #[must_use]
    pub fn with_skill_reload(
        mut self,
        paths: Vec<PathBuf>,
        rx: mpsc::Receiver<SkillEvent>,
    ) -> Self {
        self.skill_state.skill_paths = paths;
        self.skill_state.skill_reload_rx = Some(rx);
        self
    }

    /// Set the directory used by `/skill install` and `/skill remove`.
    #[must_use]
    pub fn with_managed_skills_dir(mut self, dir: PathBuf) -> Self {
        self.skill_state.managed_dir = Some(dir);
        self
    }

    /// Set the skill trust configuration (allowlists, sandbox flags).
    #[must_use]
    pub fn with_trust_config(mut self, config: crate::config::TrustConfig) -> Self {
        self.skill_state.trust_config = config;
        self
    }

    /// Configure skill matching parameters (disambiguation, two-stage, confusability).
    #[must_use]
    pub fn with_skill_matching_config(
        mut self,
        disambiguation_threshold: f32,
        two_stage_matching: bool,
        confusability_threshold: f32,
    ) -> Self {
        self.skill_state.disambiguation_threshold = disambiguation_threshold;
        self.skill_state.two_stage_matching = two_stage_matching;
        self.skill_state.confusability_threshold = confusability_threshold.clamp(0.0, 1.0);
        self
    }

    /// Override the embedding model name used for skill matching.
    #[must_use]
    pub fn with_embedding_model(mut self, model: String) -> Self {
        self.skill_state.embedding_model = model;
        self
    }

    /// Set the dedicated embedding provider (resolved once at bootstrap, never changed by
    /// `/provider switch`). When not called, defaults to the primary provider clone set in
    /// `Agent::new`.
    #[must_use]
    pub fn with_embedding_provider(mut self, provider: AnyProvider) -> Self {
        self.embedding_provider = provider;
        self
    }

    /// Enable BM25 hybrid search alongside embedding-based skill matching.
    ///
    /// # Panics
    ///
    #[must_use]
    pub fn with_hybrid_search(mut self, enabled: bool) -> Self {
        self.skill_state.hybrid_search = enabled;
        if enabled {
            let reg = self.skill_state.registry.read();
            let all_meta = reg.all_meta();
            let descs: Vec<&str> = all_meta.iter().map(|m| m.description.as_str()).collect();
            self.skill_state.bm25_index = Some(zeph_skills::bm25::Bm25Index::build(&descs));
        }
        self
    }

    /// Configure the `SkillOrchestra` RL routing head.
    ///
    /// When `enabled = false`, the head is not loaded and re-ranking is skipped.
    #[must_use]
    pub fn with_rl_routing(
        mut self,
        enabled: bool,
        learning_rate: f32,
        rl_weight: f32,
        persist_interval: u32,
        warmup_updates: u32,
    ) -> Self {
        self.learning_engine.rl_routing = Some(crate::agent::learning_engine::RlRoutingConfig {
            enabled,
            learning_rate,
            persist_interval,
        });
        self.skill_state.rl_weight = rl_weight;
        self.skill_state.rl_warmup_updates = warmup_updates;
        self
    }

    /// Attach a pre-loaded RL routing head (loaded from DB weights at startup).
    #[must_use]
    pub fn with_rl_head(mut self, head: zeph_skills::rl_head::RoutingHead) -> Self {
        self.skill_state.rl_head = Some(head);
        self
    }

    // ---- Providers ----

    /// Set the dedicated summarization provider used for compaction LLM calls.
    #[must_use]
    pub fn with_summary_provider(mut self, provider: AnyProvider) -> Self {
        self.providers.summary_provider = Some(provider);
        self
    }

    /// Set the judge provider for feedback-based correction detection.
    #[must_use]
    pub fn with_judge_provider(mut self, provider: AnyProvider) -> Self {
        self.providers.judge_provider = Some(provider);
        self
    }

    /// Set the probe provider for compaction probing LLM calls.
    ///
    /// Falls back to `summary_provider` (or primary) when `None`.
    #[must_use]
    pub fn with_probe_provider(mut self, provider: AnyProvider) -> Self {
        self.providers.probe_provider = Some(provider);
        self
    }

    /// Set a dedicated provider for `compress_context` LLM calls (#2356).
    ///
    /// When not set, `handle_compress_context` falls back to the primary provider.
    #[must_use]
    pub fn with_compress_provider(mut self, provider: AnyProvider) -> Self {
        self.providers.compress_provider = Some(provider);
        self
    }

    /// Set the planner provider for `LlmPlanner` orchestration calls.
    #[must_use]
    pub fn with_planner_provider(mut self, provider: AnyProvider) -> Self {
        self.orchestration.planner_provider = Some(provider);
        self
    }

    /// Set a dedicated provider for `PlanVerifier` LLM calls.
    ///
    /// When not set, verification falls back to the primary provider.
    #[must_use]
    pub fn with_verify_provider(mut self, provider: AnyProvider) -> Self {
        self.orchestration.verify_provider = Some(provider);
        self
    }

    /// Set a dedicated judge provider for experiment evaluation.
    ///
    /// When set, the evaluator uses this provider instead of the agent's primary provider,
    /// eliminating self-judge bias. Corresponds to `experiments.eval_model` in config.
    #[must_use]
    pub fn with_eval_provider(mut self, provider: AnyProvider) -> Self {
        self.experiments.eval_provider = Some(provider);
        self
    }

    /// Store the provider pool and config snapshot for runtime `/provider` switching.
    #[must_use]
    pub fn with_provider_pool(
        mut self,
        pool: Vec<ProviderEntry>,
        snapshot: ProviderConfigSnapshot,
    ) -> Self {
        self.providers.provider_pool = pool;
        self.providers.provider_config_snapshot = Some(snapshot);
        self
    }

    /// Inject a shared provider override slot for runtime model switching (e.g. via ACP
    /// `set_session_config_option`). The agent checks and swaps the provider before each turn.
    #[must_use]
    pub fn with_provider_override(mut self, slot: Arc<RwLock<Option<AnyProvider>>>) -> Self {
        self.providers.provider_override = Some(slot);
        self
    }

    /// Set the configured provider name (from `[[llm.providers]]` `name` field).
    ///
    /// Used by the TUI metrics panel and `/provider status` to display the logical name
    /// instead of the provider type string returned by `LlmProvider::name()`.
    #[must_use]
    pub fn with_active_provider_name(mut self, name: impl Into<String>) -> Self {
        self.runtime.active_provider_name = name.into();
        self
    }

    /// Attach a speech-to-text backend for voice input.
    #[must_use]
    pub fn with_stt(mut self, stt: Box<dyn zeph_llm::stt::SpeechToText>) -> Self {
        self.providers.stt = Some(stt);
        self
    }

    // ---- MCP ----

    /// Attach MCP tools, registry, manager, and connection parameters.
    #[must_use]
    pub fn with_mcp(
        mut self,
        tools: Vec<zeph_mcp::McpTool>,
        registry: Option<zeph_mcp::McpToolRegistry>,
        manager: Option<std::sync::Arc<zeph_mcp::McpManager>>,
        mcp_config: &crate::config::McpConfig,
    ) -> Self {
        self.mcp.tools = tools;
        self.mcp.registry = registry;
        self.mcp.manager = manager;
        self.mcp
            .allowed_commands
            .clone_from(&mcp_config.allowed_commands);
        self.mcp.max_dynamic = mcp_config.max_dynamic_servers;
        self.mcp.elicitation_warn_sensitive_fields = mcp_config.elicitation_warn_sensitive_fields;
        self
    }

    /// Store the per-server connection outcomes for TUI and `/status` display.
    #[must_use]
    pub fn with_mcp_server_outcomes(
        mut self,
        outcomes: Vec<zeph_mcp::ServerConnectOutcome>,
    ) -> Self {
        self.mcp.server_outcomes = outcomes;
        self
    }

    /// Attach the shared MCP tool list (updated dynamically when servers reconnect).
    #[must_use]
    pub fn with_mcp_shared_tools(mut self, shared: Arc<RwLock<Vec<zeph_mcp::McpTool>>>) -> Self {
        self.mcp.shared_tools = Some(shared);
        self
    }

    /// Configure MCP tool pruning (#2298).
    ///
    /// Sets the pruning params derived from `ToolPruningConfig` and optionally a dedicated
    /// provider for pruning LLM calls.  `pruning_provider = None` means fall back to the
    /// primary provider.
    #[must_use]
    pub fn with_mcp_pruning(
        mut self,
        params: zeph_mcp::PruningParams,
        enabled: bool,
        pruning_provider: Option<zeph_llm::any::AnyProvider>,
    ) -> Self {
        self.mcp.pruning_params = params;
        self.mcp.pruning_enabled = enabled;
        self.mcp.pruning_provider = pruning_provider;
        self
    }

    /// Configure embedding-based MCP tool discovery (#2321).
    ///
    /// Sets the discovery strategy, parameters, and optionally a dedicated embedding provider.
    /// `discovery_provider = None` means fall back to the agent's primary embedding provider.
    #[must_use]
    pub fn with_mcp_discovery(
        mut self,
        strategy: zeph_mcp::ToolDiscoveryStrategy,
        params: zeph_mcp::DiscoveryParams,
        discovery_provider: Option<zeph_llm::any::AnyProvider>,
    ) -> Self {
        self.mcp.discovery_strategy = strategy;
        self.mcp.discovery_params = params;
        self.mcp.discovery_provider = discovery_provider;
        self
    }

    /// Set the watch receiver for MCP tool list updates from `tools/list_changed` notifications.
    ///
    /// The agent polls this receiver at the start of each turn to pick up refreshed tool lists.
    #[must_use]
    pub fn with_mcp_tool_rx(
        mut self,
        rx: tokio::sync::watch::Receiver<Vec<zeph_mcp::McpTool>>,
    ) -> Self {
        self.mcp.tool_rx = Some(rx);
        self
    }

    /// Set the elicitation receiver for MCP elicitation requests from server handlers.
    ///
    /// When set, the agent loop processes elicitation events concurrently with tool result
    /// awaiting to prevent deadlock.
    #[must_use]
    pub fn with_mcp_elicitation_rx(
        mut self,
        rx: tokio::sync::mpsc::Receiver<zeph_mcp::ElicitationEvent>,
    ) -> Self {
        self.mcp.elicitation_rx = Some(rx);
        self
    }

    // ---- Security ----

    /// Apply the full security configuration: sanitizers, exfiltration guard, PII filter,
    /// rate limiter, and pre-execution verifiers.
    #[must_use]
    pub fn with_security(mut self, security: SecurityConfig, timeouts: TimeoutConfig) -> Self {
        self.security.sanitizer =
            zeph_sanitizer::ContentSanitizer::new(&security.content_isolation);
        self.security.exfiltration_guard = zeph_sanitizer::exfiltration::ExfiltrationGuard::new(
            security.exfiltration_guard.clone(),
        );
        self.security.pii_filter = zeph_sanitizer::pii::PiiFilter::new(security.pii_filter.clone());
        self.security.memory_validator =
            zeph_sanitizer::memory_validation::MemoryWriteValidator::new(
                security.memory_validation.clone(),
            );
        self.runtime.rate_limiter =
            crate::agent::rate_limiter::ToolRateLimiter::new(security.rate_limit.clone());

        // Build pre-execution verifiers from config.
        // Stored on ToolOrchestrator (not SecurityState) — verifiers inspect tool arguments
        // at dispatch time, consistent with repeat-detection and rate-limiting which also
        // live on ToolOrchestrator. SecurityState hosts zeph-core::sanitizer types only.
        let mut verifiers: Vec<Box<dyn zeph_tools::PreExecutionVerifier>> = Vec::new();
        if security.pre_execution_verify.enabled {
            let dcfg = &security.pre_execution_verify.destructive_commands;
            if dcfg.enabled {
                verifiers.push(Box::new(zeph_tools::DestructiveCommandVerifier::new(dcfg)));
            }
            let icfg = &security.pre_execution_verify.injection_patterns;
            if icfg.enabled {
                verifiers.push(Box::new(zeph_tools::InjectionPatternVerifier::new(icfg)));
            }
            let ucfg = &security.pre_execution_verify.url_grounding;
            if ucfg.enabled {
                verifiers.push(Box::new(zeph_tools::UrlGroundingVerifier::new(
                    ucfg,
                    std::sync::Arc::clone(&self.security.user_provided_urls),
                )));
            }
            let fcfg = &security.pre_execution_verify.firewall;
            if fcfg.enabled {
                verifiers.push(Box::new(zeph_tools::FirewallVerifier::new(fcfg)));
            }
        }
        self.tool_orchestrator.pre_execution_verifiers = verifiers;

        self.security.response_verifier = zeph_sanitizer::response_verifier::ResponseVerifier::new(
            security.response_verification.clone(),
        );

        self.runtime.security = security;
        self.runtime.timeouts = timeouts;
        self
    }

    /// Attach a `QuarantinedSummarizer` for MCP cross-boundary audit.
    #[must_use]
    pub fn with_quarantine_summarizer(
        mut self,
        qs: zeph_sanitizer::quarantine::QuarantinedSummarizer,
    ) -> Self {
        self.security.quarantine_summarizer = Some(qs);
        self
    }

    /// Mark this agent session as serving an ACP client.
    /// When `true` and `mcp_to_acp_boundary` is enabled, MCP tool results
    /// receive unconditional quarantine and cross-boundary audit logging.
    #[must_use]
    pub fn with_acp_session(mut self, is_acp: bool) -> Self {
        self.security.is_acp_session = is_acp;
        self
    }

    /// Attach a temporal causal IPI analyzer.
    ///
    /// When `Some`, the native tool dispatch loop runs pre/post behavioral probes.
    #[must_use]
    pub fn with_causal_analyzer(
        mut self,
        analyzer: zeph_sanitizer::causal_ipi::TurnCausalAnalyzer,
    ) -> Self {
        self.security.causal_analyzer = Some(analyzer);
        self
    }

    /// Attach an ML classifier backend to the sanitizer for injection detection.
    ///
    /// When attached, `classify_injection()` is called on each incoming user message when
    /// `classifiers.enabled = true`. On error or timeout it falls back to regex detection.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_injection_classifier(
        mut self,
        backend: std::sync::Arc<dyn zeph_llm::classifier::ClassifierBackend>,
        timeout_ms: u64,
        threshold: f32,
        threshold_soft: f32,
    ) -> Self {
        // Replace sanitizer in-place: move out, attach classifier, move back.
        let old = std::mem::replace(
            &mut self.security.sanitizer,
            zeph_sanitizer::ContentSanitizer::new(
                &zeph_sanitizer::ContentIsolationConfig::default(),
            ),
        );
        self.security.sanitizer = old
            .with_classifier(backend, timeout_ms, threshold)
            .with_injection_threshold_soft(threshold_soft);
        self
    }

    /// Set the enforcement mode for the injection classifier.
    ///
    /// `Warn` (default): scores above the hard threshold emit WARN + metric but do NOT block.
    /// `Block`: scores above the hard threshold block content.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_enforcement_mode(mut self, mode: zeph_config::InjectionEnforcementMode) -> Self {
        let old = std::mem::replace(
            &mut self.security.sanitizer,
            zeph_sanitizer::ContentSanitizer::new(
                &zeph_sanitizer::ContentIsolationConfig::default(),
            ),
        );
        self.security.sanitizer = old.with_enforcement_mode(mode);
        self
    }

    /// Attach a three-class classifier backend for `AlignSentinel` injection refinement.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_three_class_classifier(
        mut self,
        backend: std::sync::Arc<dyn zeph_llm::classifier::ClassifierBackend>,
        threshold: f32,
    ) -> Self {
        let old = std::mem::replace(
            &mut self.security.sanitizer,
            zeph_sanitizer::ContentSanitizer::new(
                &zeph_sanitizer::ContentIsolationConfig::default(),
            ),
        );
        self.security.sanitizer = old.with_three_class_backend(backend, threshold);
        self
    }

    /// Configure whether the ML classifier runs on direct user chat messages.
    ///
    /// Default `false`. See `ClassifiersConfig::scan_user_input` for rationale.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_scan_user_input(mut self, value: bool) -> Self {
        let old = std::mem::replace(
            &mut self.security.sanitizer,
            zeph_sanitizer::ContentSanitizer::new(
                &zeph_sanitizer::ContentIsolationConfig::default(),
            ),
        );
        self.security.sanitizer = old.with_scan_user_input(value);
        self
    }

    /// Attach a PII detector backend to the sanitizer.
    ///
    /// When attached, `detect_pii()` is called on outgoing assistant responses when
    /// `classifiers.pii_enabled = true`. On error it falls back to returning no spans.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_pii_detector(
        mut self,
        detector: std::sync::Arc<dyn zeph_llm::classifier::PiiDetector>,
        threshold: f32,
    ) -> Self {
        let old = std::mem::replace(
            &mut self.security.sanitizer,
            zeph_sanitizer::ContentSanitizer::new(
                &zeph_sanitizer::ContentIsolationConfig::default(),
            ),
        );
        self.security.sanitizer = old.with_pii_detector(detector, threshold);
        self
    }

    /// Set the NER PII allowlist on the sanitizer.
    ///
    /// Span texts matching any allowlist entry (case-insensitive, exact) are suppressed
    /// from `detect_pii()` results. Must be called after `with_pii_detector`.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_pii_ner_allowlist(mut self, entries: Vec<String>) -> Self {
        let old = std::mem::replace(
            &mut self.security.sanitizer,
            zeph_sanitizer::ContentSanitizer::new(
                &zeph_sanitizer::ContentIsolationConfig::default(),
            ),
        );
        self.security.sanitizer = old.with_pii_ner_allowlist(entries);
        self
    }

    /// Attach a NER classifier backend for PII detection in the union merge pipeline.
    ///
    /// When attached, `sanitize_tool_output()` runs both regex and NER, merges spans, and
    /// redacts from the merged list in a single pass. References `classifiers.ner_model`.
    #[cfg(feature = "classifiers")]
    #[must_use]
    pub fn with_pii_ner_classifier(
        mut self,
        backend: std::sync::Arc<dyn zeph_llm::classifier::ClassifierBackend>,
        timeout_ms: u64,
        max_chars: usize,
        circuit_breaker_threshold: u32,
    ) -> Self {
        self.security.pii_ner_backend = Some(backend);
        self.security.pii_ner_timeout_ms = timeout_ms;
        self.security.pii_ner_max_chars = max_chars;
        self.security.pii_ner_circuit_breaker_threshold = circuit_breaker_threshold;
        self
    }

    /// Attach a guardrail filter for output safety checking.
    #[must_use]
    pub fn with_guardrail(mut self, filter: zeph_sanitizer::guardrail::GuardrailFilter) -> Self {
        use zeph_sanitizer::guardrail::GuardrailAction;
        let warn_mode = filter.action() == GuardrailAction::Warn;
        self.security.guardrail = Some(filter);
        self.update_metrics(|m| {
            m.guardrail_enabled = true;
            m.guardrail_warn_mode = warn_mode;
        });
        self
    }

    /// Attach an audit logger for pre-execution verifier blocks.
    #[must_use]
    pub fn with_audit_logger(mut self, logger: std::sync::Arc<zeph_tools::AuditLogger>) -> Self {
        self.tool_orchestrator.audit_logger = Some(logger);
        self
    }

    // ---- Context & Compression ----

    /// Configure the context token budget and compaction thresholds.
    #[must_use]
    pub fn with_context_budget(
        mut self,
        budget_tokens: usize,
        reserve_ratio: f32,
        hard_compaction_threshold: f32,
        compaction_preserve_tail: usize,
        prune_protect_tokens: usize,
    ) -> Self {
        if budget_tokens == 0 {
            tracing::warn!("context budget is 0 — agent will have no token tracking");
        }
        if budget_tokens > 0 {
            self.context_manager.budget = Some(ContextBudget::new(budget_tokens, reserve_ratio));
        }
        self.context_manager.hard_compaction_threshold = hard_compaction_threshold;
        self.context_manager.compaction_preserve_tail = compaction_preserve_tail;
        self.context_manager.prune_protect_tokens = prune_protect_tokens;
        self
    }

    /// Apply the compression strategy configuration.
    #[must_use]
    pub fn with_compression(mut self, compression: CompressionConfig) -> Self {
        self.context_manager.compression = compression;
        self
    }

    /// Set the memory store routing config (heuristic vs. embedding-based).
    #[must_use]
    pub fn with_routing(mut self, routing: StoreRoutingConfig) -> Self {
        self.context_manager.routing = routing;
        self
    }

    /// Configure `Focus` and `SideQuest` LLM-driven context management (#1850, #1885).
    #[must_use]
    pub fn with_focus_and_sidequest_config(
        mut self,
        focus: crate::config::FocusConfig,
        sidequest: crate::config::SidequestConfig,
    ) -> Self {
        self.focus = super::focus::FocusState::new(focus);
        self.sidequest = super::sidequest::SidequestState::new(sidequest);
        self
    }

    // ---- Tools ----

    /// Wrap the current tool executor with an additional executor via `CompositeExecutor`.
    #[must_use]
    pub fn add_tool_executor(
        mut self,
        extra: impl zeph_tools::executor::ToolExecutor + 'static,
    ) -> Self {
        let existing = Arc::clone(&self.tool_executor);
        let combined = zeph_tools::CompositeExecutor::new(zeph_tools::DynExecutor(existing), extra);
        self.tool_executor = Arc::new(combined);
        self
    }

    /// Configure Think-Augmented Function Calling (TAFC).
    ///
    /// `complexity_threshold` is clamped to [0.0, 1.0]; NaN / Inf are reset to 0.6.
    #[must_use]
    pub fn with_tafc_config(mut self, config: zeph_tools::TafcConfig) -> Self {
        self.tool_orchestrator.tafc = config.validated();
        self
    }

    /// Set dependency config parameters (boost values) used per-turn.
    #[must_use]
    pub fn with_dependency_config(mut self, config: zeph_tools::DependencyConfig) -> Self {
        self.runtime.dependency_config = config;
        self
    }

    /// Attach a tool dependency graph for sequential tool availability (issue #2024).
    ///
    /// When set, hard gates (`requires`) are applied after schema filtering, and soft boosts
    /// (`prefers`) are added to similarity scores. Always-on tool IDs bypass hard gates.
    #[must_use]
    pub fn with_tool_dependency_graph(
        mut self,
        graph: zeph_tools::ToolDependencyGraph,
        always_on: std::collections::HashSet<String>,
    ) -> Self {
        self.tool_state.dependency_graph = Some(graph);
        self.tool_state.dependency_always_on = always_on;
        self
    }

    /// Initialize and attach the tool schema filter if enabled in config.
    ///
    /// Embeds all filterable tool descriptions at startup and caches the embeddings.
    /// Gracefully degrades: returns `self` unchanged if embedding is unsupported or fails.
    pub async fn maybe_init_tool_schema_filter(
        mut self,
        config: &crate::config::ToolFilterConfig,
        provider: &zeph_llm::any::AnyProvider,
    ) -> Self {
        use zeph_llm::provider::LlmProvider;

        if !config.enabled {
            return self;
        }

        let always_on_set: std::collections::HashSet<&str> =
            config.always_on.iter().map(String::as_str).collect();
        let defs = self.tool_executor.tool_definitions_erased();
        let filterable: Vec<&zeph_tools::registry::ToolDef> = defs
            .iter()
            .filter(|d| !always_on_set.contains(d.id.as_ref()))
            .collect();

        if filterable.is_empty() {
            tracing::info!("tool schema filter: all tools are always-on, nothing to filter");
            return self;
        }

        let mut embeddings = Vec::with_capacity(filterable.len());
        for def in &filterable {
            let text = format!("{}: {}", def.id, def.description);
            match provider.embed(&text).await {
                Ok(emb) => {
                    embeddings.push(zeph_tools::ToolEmbedding {
                        tool_id: def.id.as_ref().into(),
                        embedding: emb,
                    });
                }
                Err(e) => {
                    tracing::info!(
                        provider = provider.name(),
                        "tool schema filter disabled: embedding not supported \
                        by provider ({e:#})"
                    );
                    return self;
                }
            }
        }

        tracing::info!(
            tool_count = embeddings.len(),
            always_on = config.always_on.len(),
            top_k = config.top_k,
            "tool schema filter initialized"
        );

        let filter = zeph_tools::ToolSchemaFilter::new(
            config.always_on.clone(),
            config.top_k,
            config.min_description_words,
            embeddings,
        );
        self.tool_state.tool_schema_filter = Some(filter);
        self
    }

    /// Add an in-process `IndexMcpServer` as a tool executor.
    ///
    /// When enabled, the LLM can call `symbol_definition`, `find_text_references`,
    /// `call_graph`, and `module_summary` tools on demand. Static repo-map injection
    /// should be disabled when this is active (set `repo_map_tokens = 0` or skip
    /// `inject_code_context`).
    #[must_use]
    pub fn with_index_mcp_server(self, project_root: impl Into<std::path::PathBuf>) -> Self {
        let server = zeph_index::IndexMcpServer::new(project_root);
        self.add_tool_executor(server)
    }

    /// Configure the in-process repo-map injector.
    #[must_use]
    pub fn with_repo_map(mut self, token_budget: usize, ttl_secs: u64) -> Self {
        self.index.repo_map_tokens = token_budget;
        self.index.repo_map_ttl = std::time::Duration::from_secs(ttl_secs);
        self
    }

    // ---- Debug & Diagnostics ----

    /// Enable debug dump mode, writing LLM requests/responses and raw tool output to `dumper`.
    #[must_use]
    pub fn with_debug_dumper(mut self, dumper: crate::debug_dump::DebugDumper) -> Self {
        self.debug_state.debug_dumper = Some(dumper);
        self
    }

    /// Enable `OTel` trace collection. The collector writes `trace.json` at session end.
    #[must_use]
    pub fn with_trace_collector(
        mut self,
        collector: crate::debug_dump::trace::TracingCollector,
    ) -> Self {
        self.debug_state.trace_collector = Some(collector);
        self
    }

    /// Store trace config so `/dump-format trace` can create a `TracingCollector` at runtime (CR-04).
    #[must_use]
    pub fn with_trace_config(
        mut self,
        dump_dir: std::path::PathBuf,
        service_name: impl Into<String>,
        redact: bool,
    ) -> Self {
        self.debug_state.dump_dir = Some(dump_dir);
        self.debug_state.trace_service_name = service_name.into();
        self.debug_state.trace_redact = redact;
        self
    }

    /// Attach an anomaly detector for turn-level error rate monitoring.
    #[must_use]
    pub fn with_anomaly_detector(mut self, detector: zeph_tools::AnomalyDetector) -> Self {
        self.debug_state.anomaly_detector = Some(detector);
        self
    }

    /// Apply the logging configuration (log level, structured output).
    #[must_use]
    pub fn with_logging_config(mut self, logging: crate::config::LoggingConfig) -> Self {
        self.debug_state.logging_config = logging;
        self
    }

    // ---- Lifecycle & Session ----

    /// Attach the graceful-shutdown receiver.
    #[must_use]
    pub fn with_shutdown(mut self, rx: watch::Receiver<bool>) -> Self {
        self.lifecycle.shutdown = rx;
        self
    }

    /// Attach the config-reload event stream.
    #[must_use]
    pub fn with_config_reload(mut self, path: PathBuf, rx: mpsc::Receiver<ConfigEvent>) -> Self {
        self.lifecycle.config_path = Some(path);
        self.lifecycle.config_reload_rx = Some(rx);
        self
    }

    /// Attach the warmup-ready signal (fires after background init completes).
    #[must_use]
    pub fn with_warmup_ready(mut self, rx: watch::Receiver<bool>) -> Self {
        self.lifecycle.warmup_ready = Some(rx);
        self
    }

    /// Attach the update-notification receiver for in-process version alerts.
    #[must_use]
    pub fn with_update_notifications(mut self, rx: mpsc::Receiver<String>) -> Self {
        self.lifecycle.update_notify_rx = Some(rx);
        self
    }

    /// Attach a custom task receiver for programmatic task injection.
    #[must_use]
    pub fn with_custom_task_rx(mut self, rx: mpsc::Receiver<String>) -> Self {
        self.lifecycle.custom_task_rx = Some(rx);
        self
    }

    /// Inject a shared cancel signal so an external caller (e.g. ACP session) can
    /// interrupt the agent loop by calling `notify_one()`.
    #[must_use]
    pub fn with_cancel_signal(mut self, signal: Arc<Notify>) -> Self {
        self.lifecycle.cancel_signal = signal;
        self
    }

    /// Configure reactive hook events from the `[hooks]` config section.
    ///
    /// Stores hook definitions in `SessionState` and starts a `FileChangeWatcher`
    /// when `file_changed.watch_paths` is non-empty. Initializes `last_known_cwd`
    /// from the current process cwd at call time (the project root).
    #[must_use]
    pub fn with_hooks_config(mut self, config: &zeph_config::HooksConfig) -> Self {
        self.session
            .hooks_config
            .cwd_changed
            .clone_from(&config.cwd_changed);

        if let Some(ref fc) = config.file_changed {
            self.session
                .hooks_config
                .file_changed_hooks
                .clone_from(&fc.hooks);

            if !fc.watch_paths.is_empty() {
                let (tx, rx) = tokio::sync::mpsc::channel(64);
                match crate::file_watcher::FileChangeWatcher::start(
                    &fc.watch_paths,
                    fc.debounce_ms,
                    tx,
                ) {
                    Ok(watcher) => {
                        self.lifecycle.file_watcher = Some(watcher);
                        self.lifecycle.file_changed_rx = Some(rx);
                        tracing::info!(
                            paths = ?fc.watch_paths,
                            debounce_ms = fc.debounce_ms,
                            "file change watcher started"
                        );
                    }
                    Err(e) => {
                        tracing::warn!(error = %e, "failed to start file change watcher");
                    }
                }
            }
        }

        // Sync last_known_cwd with env_context.working_dir if already set.
        let cwd_str = &self.session.env_context.working_dir;
        if !cwd_str.is_empty() {
            self.lifecycle.last_known_cwd = std::path::PathBuf::from(cwd_str);
        }

        self
    }

    /// Set the working directory and initialise the environment context snapshot.
    #[must_use]
    pub fn with_working_dir(mut self, path: impl Into<PathBuf>) -> Self {
        let path = path.into();
        self.session.env_context =
            crate::context::EnvironmentContext::gather_for_dir(&self.runtime.model_name, &path);
        self
    }

    /// Store a snapshot of the policy config for `/policy` command inspection.
    #[must_use]
    pub fn with_policy_config(mut self, config: zeph_tools::PolicyConfig) -> Self {
        self.session.policy_config = Some(config);
        self
    }

    /// Set the parent tool call ID for subagent sessions.
    ///
    /// When set, every `LoopbackEvent::ToolStart` and `LoopbackEvent::ToolOutput` emitted
    /// by this agent will carry the `parent_tool_use_id` so the IDE can build a subagent
    /// hierarchy tree.
    #[must_use]
    pub fn with_parent_tool_use_id(mut self, id: impl Into<String>) -> Self {
        self.session.parent_tool_use_id = Some(id.into());
        self
    }

    /// Attach a cached response store for per-session deduplication.
    #[must_use]
    pub fn with_response_cache(
        mut self,
        cache: std::sync::Arc<zeph_memory::ResponseCache>,
    ) -> Self {
        self.session.response_cache = Some(cache);
        self
    }

    /// Enable LSP context injection hooks (diagnostics-on-save, hover-on-read).
    #[must_use]
    pub fn with_lsp_hooks(mut self, runner: crate::lsp_hooks::LspHookRunner) -> Self {
        self.session.lsp_hooks = Some(runner);
        self
    }

    /// Configure the background task supervisor with explicit limits and optional recorder.
    ///
    /// Re-initialises the supervisor from `config`. Call this after
    /// [`with_histogram_recorder`][Self::with_histogram_recorder] so the recorder is
    /// available for passing to the supervisor.
    #[must_use]
    pub fn with_supervisor_config(mut self, config: &crate::config::TaskSupervisorConfig) -> Self {
        self.lifecycle.supervisor = crate::agent::supervisor::BackgroundSupervisor::new(
            config,
            self.metrics.histogram_recorder.clone(),
        );
        self.runtime.supervisor_config = config.clone();
        self
    }

    /// Returns a handle that can cancel the current in-flight operation.
    /// The returned `Notify` is stable across messages — callers invoke
    /// `notify_waiters()` to cancel whatever operation is running.
    #[must_use]
    pub fn cancel_signal(&self) -> Arc<Notify> {
        Arc::clone(&self.lifecycle.cancel_signal)
    }

    // ---- Metrics ----

    /// Wire the metrics broadcast channel and emit the initial snapshot.
    #[must_use]
    pub fn with_metrics(mut self, tx: watch::Sender<MetricsSnapshot>) -> Self {
        let provider_name = if self.runtime.active_provider_name.is_empty() {
            self.provider.name().to_owned()
        } else {
            self.runtime.active_provider_name.clone()
        };
        let model_name = self.runtime.model_name.clone();
        let total_skills = self.skill_state.registry.read().all_meta().len();
        let qdrant_available = false;
        let conversation_id = self.memory_state.persistence.conversation_id;
        let prompt_estimate = self
            .msg
            .messages
            .first()
            .map_or(0, |m| u64::try_from(m.content.len()).unwrap_or(0) / 4);
        let mcp_tool_count = self.mcp.tools.len();
        let mcp_server_count = if self.mcp.server_outcomes.is_empty() {
            // Fallback: count unique server IDs from connected tools
            self.mcp
                .tools
                .iter()
                .map(|t| &t.server_id)
                .collect::<std::collections::HashSet<_>>()
                .len()
        } else {
            self.mcp.server_outcomes.len()
        };
        let mcp_connected_count = if self.mcp.server_outcomes.is_empty() {
            mcp_server_count
        } else {
            self.mcp
                .server_outcomes
                .iter()
                .filter(|o| o.connected)
                .count()
        };
        let mcp_servers: Vec<crate::metrics::McpServerStatus> = self
            .mcp
            .server_outcomes
            .iter()
            .map(|o| crate::metrics::McpServerStatus {
                id: o.id.clone(),
                status: if o.connected {
                    crate::metrics::McpServerConnectionStatus::Connected
                } else {
                    crate::metrics::McpServerConnectionStatus::Failed
                },
                tool_count: o.tool_count,
                error: o.error.clone(),
            })
            .collect();
        let extended_context = self.metrics.extended_context;
        tx.send_modify(|m| {
            m.provider_name = provider_name;
            m.model_name = model_name;
            m.total_skills = total_skills;
            m.qdrant_available = qdrant_available;
            m.sqlite_conversation_id = conversation_id;
            m.context_tokens = prompt_estimate;
            m.prompt_tokens = prompt_estimate;
            m.total_tokens = prompt_estimate;
            m.mcp_tool_count = mcp_tool_count;
            m.mcp_server_count = mcp_server_count;
            m.mcp_connected_count = mcp_connected_count;
            m.mcp_servers = mcp_servers;
            m.extended_context = extended_context;
        });
        self.metrics.metrics_tx = Some(tx);
        self
    }

    /// Attach a cost tracker for per-session token budget accounting.
    #[must_use]
    pub fn with_cost_tracker(mut self, tracker: CostTracker) -> Self {
        self.metrics.cost_tracker = Some(tracker);
        self
    }

    /// Enable Claude extended-context mode tracking in metrics.
    #[must_use]
    pub fn with_extended_context(mut self, enabled: bool) -> Self {
        self.metrics.extended_context = enabled;
        self
    }

    /// Attach a histogram recorder for per-event Prometheus observations.
    ///
    /// When set, the agent records individual LLM call, turn, and tool execution
    /// latencies into the provided recorder. The recorder must be `Send + Sync`
    /// and is shared across the agent loop via `Arc`.
    ///
    /// Pass `None` to disable histogram recording (the default).
    #[must_use]
    pub fn with_histogram_recorder(
        mut self,
        recorder: Option<std::sync::Arc<dyn crate::metrics::HistogramRecorder>>,
    ) -> Self {
        self.metrics.histogram_recorder = recorder;
        self
    }

    // ---- Orchestration ----

    /// Configure orchestration, subagent management, and experiment baseline in a single call.
    ///
    /// Replaces the former `with_orchestration_config`, `with_subagent_manager`, and
    /// `with_subagent_config` methods. All three are always configured together at the
    /// call site in `runner.rs`, so they are grouped here to reduce boilerplate.
    #[must_use]
    pub fn with_orchestration(
        mut self,
        config: crate::config::OrchestrationConfig,
        subagent_config: crate::config::SubAgentConfig,
        manager: zeph_subagent::SubAgentManager,
    ) -> Self {
        self.orchestration.orchestration_config = config;
        self.orchestration.subagent_config = subagent_config;
        self.orchestration.subagent_manager = Some(manager);
        self
    }

    /// Store adversarial policy gate info for `/status` display.
    #[must_use]
    pub fn with_adversarial_policy_info(
        mut self,
        info: crate::agent::state::AdversarialPolicyInfo,
    ) -> Self {
        self.runtime.adversarial_policy_info = Some(info);
        self
    }

    // ---- Experiments ----

    /// Set the experiment configuration and baseline config snapshot together.
    ///
    /// Replaces the former `with_experiment_config` and `with_experiment_baseline` methods.
    /// Both are always set together at the call site, so they are grouped here to reduce
    /// boilerplate.
    ///
    /// `baseline` should be built via `ConfigSnapshot::from_config(&config)` so the experiment
    /// engine uses actual runtime config values (temperature, memory params, etc.) rather than
    /// hardcoded defaults.
    #[must_use]
    pub fn with_experiment(
        mut self,
        config: crate::config::ExperimentConfig,
        baseline: zeph_experiments::ConfigSnapshot,
    ) -> Self {
        self.experiments.config = config;
        self.experiments.baseline = baseline;
        self
    }

    // ---- Learning ----

    /// Apply the learning configuration (correction detection, RL routing, classifier mode).
    #[must_use]
    pub fn with_learning(mut self, config: LearningConfig) -> Self {
        if config.correction_detection {
            self.feedback.detector = super::feedback_detector::FeedbackDetector::new(
                config.correction_confidence_threshold,
            );
            if config.detector_mode == crate::config::DetectorMode::Judge {
                self.feedback.judge = Some(super::feedback_detector::JudgeDetector::new(
                    config.judge_adaptive_low,
                    config.judge_adaptive_high,
                ));
            }
        }
        self.learning_engine.config = Some(config);
        self
    }

    /// Attach an `LlmClassifier` for `detector_mode = "model"` feedback detection.
    ///
    /// When attached, the model-based path is used instead of `JudgeDetector`.
    /// The classifier resolves the provider at construction time — if the provider
    /// is unavailable, do not call this method (fallback to regex-only).
    #[must_use]
    pub fn with_llm_classifier(
        mut self,
        classifier: zeph_llm::classifier::llm::LlmClassifier,
    ) -> Self {
        // If classifier_metrics is already set, wire it into the LlmClassifier for Feedback recording.
        #[cfg(feature = "classifiers")]
        let classifier = if let Some(ref m) = self.metrics.classifier_metrics {
            classifier.with_metrics(std::sync::Arc::clone(m))
        } else {
            classifier
        };
        self.feedback.llm_classifier = Some(classifier);
        self
    }

    /// Configure the per-channel skill overrides (channel-specific skill resolution).
    #[must_use]
    pub fn with_channel_skills(mut self, config: zeph_config::ChannelSkillsConfig) -> Self {
        self.runtime.channel_skills = config;
        self
    }

    // ---- Internal helpers (pub(super)) ----

    pub(super) fn summary_or_primary_provider(&self) -> &AnyProvider {
        self.providers
            .summary_provider
            .as_ref()
            .unwrap_or(&self.provider)
    }

    pub(super) fn probe_or_summary_provider(&self) -> &AnyProvider {
        self.providers
            .probe_provider
            .as_ref()
            .or(self.providers.summary_provider.as_ref())
            .unwrap_or(&self.provider)
    }

    /// Extract the last assistant message, truncated to 500 chars, for the judge prompt.
    pub(super) fn last_assistant_response(&self) -> String {
        self.msg
            .messages
            .iter()
            .rev()
            .find(|m| m.role == zeph_llm::provider::Role::Assistant)
            .map(|m| super::context::truncate_chars(&m.content, 500))
            .unwrap_or_default()
    }

    /// Apply all config-derived settings from [`AgentSessionConfig`] in a single call.
    ///
    /// Takes `cfg` by value and destructures it so the compiler emits an unused-variable warning
    /// for any field that is added to [`AgentSessionConfig`] but not consumed here (S4).
    ///
    /// Per-session wiring (`cancel_signal`, `provider_override`, `memory`, `debug_dumper`, etc.)
    /// must still be applied separately after this call, since those depend on runtime state.
    #[must_use]
    #[allow(clippy::too_many_lines)] // flat struct literal — adding three small config fields crossed the 100-line limit
    pub fn apply_session_config(mut self, cfg: AgentSessionConfig) -> Self {
        let AgentSessionConfig {
            max_tool_iterations,
            max_tool_retries,
            max_retry_duration_secs,
            retry_base_ms,
            retry_max_ms,
            parameter_reformat_provider,
            tool_repeat_threshold,
            tool_summarization,
            tool_call_cutoff,
            max_tool_calls_per_session,
            overflow_config,
            permission_policy,
            model_name,
            embed_model,
            semantic_cache_enabled,
            semantic_cache_threshold,
            semantic_cache_max_candidates,
            budget_tokens,
            soft_compaction_threshold,
            hard_compaction_threshold,
            compaction_preserve_tail,
            compaction_cooldown_turns,
            prune_protect_tokens,
            redact_credentials,
            security,
            timeouts,
            learning,
            document_config,
            graph_config,
            persona_config,
            trajectory_config,
            category_config,
            tree_config,
            microcompact_config,
            autodream_config,
            magic_docs_config,
            anomaly_config,
            result_cache_config,
            mut utility_config,
            orchestration_config,
            // Not applied here: caller clones this before `apply_session_config` and applies
            // it per-session (e.g. `spawn_acp_agent` passes it to `with_debug_config`).
            debug_config: _debug_config,
            server_compaction,
            budget_hint_enabled,
            secrets,
        } = cfg;

        self.tool_orchestrator.apply_config(
            max_tool_iterations,
            max_tool_retries,
            max_retry_duration_secs,
            retry_base_ms,
            retry_max_ms,
            parameter_reformat_provider,
            tool_repeat_threshold,
            max_tool_calls_per_session,
            tool_summarization,
            overflow_config,
        );
        self.runtime.permission_policy = permission_policy;
        self.runtime.model_name = model_name;
        self.skill_state.embedding_model = embed_model;
        self.context_manager.apply_budget_config(
            budget_tokens,
            CONTEXT_BUDGET_RESERVE_RATIO,
            hard_compaction_threshold,
            compaction_preserve_tail,
            prune_protect_tokens,
            soft_compaction_threshold,
            compaction_cooldown_turns,
        );
        self = self
            .with_security(security, timeouts)
            .with_learning(learning);
        self.runtime.redact_credentials = redact_credentials;
        self.memory_state.persistence.tool_call_cutoff = tool_call_cutoff;
        self.skill_state.available_custom_secrets = secrets
            .iter()
            .map(|(k, v)| (k.clone(), crate::vault::Secret::new(v.expose().to_owned())))
            .collect();
        self.providers.server_compaction_active = server_compaction;
        self.memory_state.extraction.document_config = document_config;
        self.memory_state
            .extraction
            .apply_graph_config(graph_config);
        self.memory_state.extraction.persona_config = persona_config;
        self.memory_state.extraction.trajectory_config = trajectory_config;
        self.memory_state.extraction.category_config = category_config;
        self.memory_state.subsystems.tree_config = tree_config;
        self.memory_state.subsystems.microcompact_config = microcompact_config;
        self.memory_state.subsystems.autodream_config = autodream_config;
        self.memory_state.subsystems.magic_docs_config = magic_docs_config;
        self.orchestration.orchestration_config = orchestration_config;
        self.runtime.budget_hint_enabled = budget_hint_enabled;

        self.debug_state.reasoning_model_warning = anomaly_config.reasoning_model_warning;
        if anomaly_config.enabled {
            self = self.with_anomaly_detector(zeph_tools::AnomalyDetector::new(
                anomaly_config.window_size,
                anomaly_config.error_threshold,
                anomaly_config.critical_threshold,
            ));
        }

        self.runtime.semantic_cache_enabled = semantic_cache_enabled;
        self.runtime.semantic_cache_threshold = semantic_cache_threshold;
        self.runtime.semantic_cache_max_candidates = semantic_cache_max_candidates;
        self.tool_orchestrator
            .set_cache_config(&result_cache_config);

        // When MagicDocs is enabled, file-read tools must bypass the utility gate so that
        // MagicDocs detection can inspect real file content (not a [skipped] sentinel).
        if self.memory_state.subsystems.magic_docs_config.enabled {
            utility_config.exempt_tools.extend(
                crate::agent::magic_docs::FILE_READ_TOOLS
                    .iter()
                    .map(|s| (*s).to_string()),
            );
            utility_config.exempt_tools.sort_unstable();
            utility_config.exempt_tools.dedup();
        }
        self.tool_orchestrator.set_utility_config(utility_config);

        self
    }

    // ---- Instruction reload ----

    /// Configure instruction block hot-reload.
    #[must_use]
    pub fn with_instruction_blocks(
        mut self,
        blocks: Vec<crate::instructions::InstructionBlock>,
    ) -> Self {
        self.instructions.blocks = blocks;
        self
    }

    /// Attach the instruction reload event stream.
    #[must_use]
    pub fn with_instruction_reload(
        mut self,
        rx: mpsc::Receiver<InstructionEvent>,
        state: InstructionReloadState,
    ) -> Self {
        self.instructions.reload_rx = Some(rx);
        self.instructions.reload_state = Some(state);
        self
    }

    /// Attach a status channel for spinner/status messages sent to TUI or stderr.
    /// The sender must be cloned from the provider's `StatusTx` before
    /// `provider.set_status_tx()` consumes it.
    #[must_use]
    pub fn with_status_tx(mut self, tx: tokio::sync::mpsc::UnboundedSender<String>) -> Self {
        self.session.status_tx = Some(tx);
        self
    }
}

#[cfg(test)]
mod tests {
    use super::super::agent_tests::{
        MockChannel, MockToolExecutor, create_test_registry, mock_provider,
    };
    use super::*;
    use crate::config::{CompressionStrategy, StoreRoutingConfig, StoreRoutingStrategy};

    fn make_agent() -> Agent<MockChannel> {
        Agent::new(
            mock_provider(vec![]),
            MockChannel::new(vec![]),
            create_test_registry(),
            None,
            5,
            MockToolExecutor::no_tools(),
        )
    }

    #[test]
    #[allow(clippy::default_trait_access)]
    fn with_compression_sets_proactive_strategy() {
        let compression = CompressionConfig {
            strategy: CompressionStrategy::Proactive {
                threshold_tokens: 50_000,
                max_summary_tokens: 2_000,
            },
            model: String::new(),
            pruning_strategy: crate::config::PruningStrategy::default(),
            probe: zeph_memory::CompactionProbeConfig::default(),
            compress_provider: zeph_config::ProviderName::default(),
            archive_tool_outputs: false,
            focus_scorer_provider: zeph_config::ProviderName::default(),
            high_density_budget: 0.7,
            low_density_budget: 0.3,
            predictor: Default::default(),
        };
        let agent = make_agent().with_compression(compression);
        assert!(
            matches!(
                agent.context_manager.compression.strategy,
                CompressionStrategy::Proactive {
                    threshold_tokens: 50_000,
                    max_summary_tokens: 2_000,
                }
            ),
            "expected Proactive strategy after with_compression"
        );
    }

    #[test]
    fn with_routing_sets_routing_config() {
        let routing = StoreRoutingConfig {
            strategy: StoreRoutingStrategy::Heuristic,
            ..StoreRoutingConfig::default()
        };
        let agent = make_agent().with_routing(routing);
        assert_eq!(
            agent.context_manager.routing.strategy,
            StoreRoutingStrategy::Heuristic,
            "routing strategy must be set by with_routing"
        );
    }

    #[test]
    fn default_compression_is_reactive() {
        let agent = make_agent();
        assert_eq!(
            agent.context_manager.compression.strategy,
            CompressionStrategy::Reactive,
            "default compression strategy must be Reactive"
        );
    }

    #[test]
    fn default_routing_is_heuristic() {
        let agent = make_agent();
        assert_eq!(
            agent.context_manager.routing.strategy,
            StoreRoutingStrategy::Heuristic,
            "default routing strategy must be Heuristic"
        );
    }

    #[test]
    fn with_cancel_signal_replaces_internal_signal() {
        let agent = Agent::new(
            mock_provider(vec![]),
            MockChannel::new(vec![]),
            create_test_registry(),
            None,
            5,
            MockToolExecutor::no_tools(),
        );

        let shared = Arc::new(Notify::new());
        let agent = agent.with_cancel_signal(Arc::clone(&shared));

        // The injected signal and the agent's internal signal must be the same Arc.
        assert!(Arc::ptr_eq(&shared, &agent.cancel_signal()));
    }

    /// Verify that `with_managed_skills_dir` enables the install/remove commands.
    /// Without a managed dir, `/skill install` sends a "not configured" message.
    /// With a managed dir configured, it proceeds past that guard (and may fail
    /// for other reasons such as the source not existing).
    #[tokio::test]
    async fn with_managed_skills_dir_enables_install_command() {
        let provider = mock_provider(vec![]);
        let channel = MockChannel::new(vec![]);
        let registry = create_test_registry();
        let executor = MockToolExecutor::no_tools();
        let managed = tempfile::tempdir().unwrap();

        let mut agent_no_dir = Agent::new(
            mock_provider(vec![]),
            MockChannel::new(vec![]),
            create_test_registry(),
            None,
            5,
            MockToolExecutor::no_tools(),
        );
        let out_no_dir = agent_no_dir
            .handle_skill_command_as_string("install /some/path")
            .await
            .unwrap();
        assert!(
            out_no_dir.contains("not configured"),
            "without managed dir: {out_no_dir:?}"
        );

        let _ = (provider, channel, registry, executor);
        let mut agent_with_dir = Agent::new(
            mock_provider(vec![]),
            MockChannel::new(vec![]),
            create_test_registry(),
            None,
            5,
            MockToolExecutor::no_tools(),
        )
        .with_managed_skills_dir(managed.path().to_path_buf());

        let out_with_dir = agent_with_dir
            .handle_skill_command_as_string("install /nonexistent/path")
            .await
            .unwrap();
        assert!(
            !out_with_dir.contains("not configured"),
            "with managed dir should not say not configured: {out_with_dir:?}"
        );
        assert!(
            out_with_dir.contains("Install failed"),
            "with managed dir should fail due to bad path: {out_with_dir:?}"
        );
    }

    #[test]
    fn default_graph_config_is_disabled() {
        let agent = make_agent();
        assert!(
            !agent.memory_state.extraction.graph_config.enabled,
            "graph_config must default to disabled"
        );
    }

    #[test]
    fn with_graph_config_enabled_sets_flag() {
        let cfg = crate::config::GraphConfig {
            enabled: true,
            ..Default::default()
        };
        let agent = make_agent().with_graph_config(cfg);
        assert!(
            agent.memory_state.extraction.graph_config.enabled,
            "with_graph_config must set enabled flag"
        );
    }

    /// Verify that `apply_session_config` wires graph memory, orchestration, and anomaly
    /// detector configs into the agent in a single call — the acceptance criterion for issue #1812.
    ///
    /// This exercises the full path: `AgentSessionConfig::from_config` → `apply_session_config` →
    /// agent internal state, confirming that all three feature configs are propagated correctly.
    #[test]
    fn apply_session_config_wires_graph_orchestration_anomaly() {
        use crate::config::Config;

        let mut config = Config::default();
        config.memory.graph.enabled = true;
        config.orchestration.enabled = true;
        config.orchestration.max_tasks = 42;
        config.tools.anomaly.enabled = true;
        config.tools.anomaly.window_size = 7;

        let session_cfg = AgentSessionConfig::from_config(&config, 100_000);

        // Precondition: from_config captured the values.
        assert!(session_cfg.graph_config.enabled);
        assert!(session_cfg.orchestration_config.enabled);
        assert_eq!(session_cfg.orchestration_config.max_tasks, 42);
        assert!(session_cfg.anomaly_config.enabled);
        assert_eq!(session_cfg.anomaly_config.window_size, 7);

        let agent = make_agent().apply_session_config(session_cfg);

        // Graph config must be set on memory_state.
        assert!(
            agent.memory_state.extraction.graph_config.enabled,
            "apply_session_config must wire graph_config into agent"
        );

        // Orchestration config must be propagated.
        assert!(
            agent.orchestration.orchestration_config.enabled,
            "apply_session_config must wire orchestration_config into agent"
        );
        assert_eq!(
            agent.orchestration.orchestration_config.max_tasks, 42,
            "orchestration max_tasks must match config"
        );

        // Anomaly detector must be created when anomaly_config.enabled = true.
        assert!(
            agent.debug_state.anomaly_detector.is_some(),
            "apply_session_config must create anomaly_detector when enabled"
        );
    }

    #[test]
    fn with_focus_and_sidequest_config_propagates() {
        let focus = crate::config::FocusConfig {
            enabled: true,
            compression_interval: 7,
            ..Default::default()
        };
        let sidequest = crate::config::SidequestConfig {
            enabled: true,
            interval_turns: 3,
            ..Default::default()
        };
        let agent = make_agent().with_focus_and_sidequest_config(focus, sidequest);
        assert!(agent.focus.config.enabled, "must set focus.enabled");
        assert_eq!(
            agent.focus.config.compression_interval, 7,
            "must propagate compression_interval"
        );
        assert!(agent.sidequest.config.enabled, "must set sidequest.enabled");
        assert_eq!(
            agent.sidequest.config.interval_turns, 3,
            "must propagate interval_turns"
        );
    }

    /// Verify that `apply_session_config` does NOT create an anomaly detector when disabled.
    #[test]
    fn apply_session_config_skips_anomaly_detector_when_disabled() {
        use crate::config::Config;

        let mut config = Config::default();
        config.tools.anomaly.enabled = false; // explicitly disable to test the disabled path
        let session_cfg = AgentSessionConfig::from_config(&config, 100_000);
        assert!(!session_cfg.anomaly_config.enabled);

        let agent = make_agent().apply_session_config(session_cfg);
        assert!(
            agent.debug_state.anomaly_detector.is_none(),
            "apply_session_config must not create anomaly_detector when disabled"
        );
    }

    #[test]
    fn with_skill_matching_config_sets_fields() {
        let agent = make_agent().with_skill_matching_config(0.7, true, 0.85);
        assert!(
            agent.skill_state.two_stage_matching,
            "with_skill_matching_config must set two_stage_matching"
        );
        assert!(
            (agent.skill_state.disambiguation_threshold - 0.7).abs() < f32::EPSILON,
            "with_skill_matching_config must set disambiguation_threshold"
        );
        assert!(
            (agent.skill_state.confusability_threshold - 0.85).abs() < f32::EPSILON,
            "with_skill_matching_config must set confusability_threshold"
        );
    }

    #[test]
    fn with_skill_matching_config_clamps_confusability() {
        let agent = make_agent().with_skill_matching_config(0.5, false, 1.5);
        assert!(
            (agent.skill_state.confusability_threshold - 1.0).abs() < f32::EPSILON,
            "with_skill_matching_config must clamp confusability above 1.0"
        );

        let agent = make_agent().with_skill_matching_config(0.5, false, -0.1);
        assert!(
            agent.skill_state.confusability_threshold.abs() < f32::EPSILON,
            "with_skill_matching_config must clamp confusability below 0.0"
        );
    }

    #[test]
    fn build_succeeds_with_provider_pool() {
        let (_tx, rx) = watch::channel(false);
        // Provide a non-empty provider pool so the model_name check is bypassed.
        let snapshot = crate::agent::state::ProviderConfigSnapshot {
            claude_api_key: None,
            openai_api_key: None,
            gemini_api_key: None,
            compatible_api_keys: std::collections::HashMap::new(),
            llm_request_timeout_secs: 30,
            embedding_model: String::new(),
        };
        let agent = make_agent()
            .with_shutdown(rx)
            .with_provider_pool(
                vec![ProviderEntry {
                    name: Some("test".into()),
                    ..Default::default()
                }],
                snapshot,
            )
            .build();
        assert!(agent.is_ok(), "build must succeed with a provider pool");
    }

    #[test]
    fn build_fails_without_provider_or_model_name() {
        let agent = make_agent().build();
        assert!(
            matches!(agent, Err(BuildError::MissingProviders)),
            "build must return MissingProviders when pool is empty and model_name is unset"
        );
    }
}