lean_ctx/tools/registered/

ctx_preload.rs

use rmcp::model::Tool;
use rmcp::ErrorData;
use serde_json::{json, Map, Value};

use crate::server::tool_trait::{get_str, McpTool, ToolContext, ToolOutput};
use crate::tool_defs::tool_def;

pub struct CtxPreloadTool;

impl McpTool for CtxPreloadTool {
    fn name(&self) -> &'static str {
        "ctx_preload"
    }

    fn tool_def(&self) -> Tool {
        tool_def(
            "ctx_preload",
            "Proactive context loader — caches task-relevant files, returns L-curve-optimized summary (~50-100 tokens vs ~5000 for individual reads).",
            json!({
                "type": "object",
                "properties": {
                    "task": {
                        "type": "string",
                        "description": "Task description (e.g. 'fix auth bug in validate_token')"
                    },
                    "path": {
                        "type": "string",
                        "description": "Project root (default: .)"
                    }
                },
                "required": ["task"]
            }),
        )
    }

    fn handle(
        &self,
        args: &Map<String, Value>,
        ctx: &ToolContext,
    ) -> Result<ToolOutput, ErrorData> {
        let task = get_str(args, "task").unwrap_or_default();

        let resolved_path = if get_str(args, "path").is_some() {
            if let Some(p) = ctx.resolved_path("path") {
                Some(p.to_string())
            } else if let Some(err) = ctx.path_error("path") {
                return Err(ErrorData::invalid_params(format!("path: {err}"), None));
            } else {
                None
            }
        } else if let Some(ref session) = ctx.session {
            let guard = crate::server::bounded_lock::read(session, "ctx_preload:session_root");
            guard.as_ref().and_then(|g| g.project_root.clone())
        } else {
            None
        };

        let cache = ctx.cache.as_ref().unwrap();
        let Some(mut cache_guard) = crate::server::bounded_lock::write(cache, "ctx_preload:cache")
        else {
            return Ok(ToolOutput::simple(
                "[preload skipped — cache temporarily unavailable]".to_string(),
            ));
        };
        let mut result = crate::tools::ctx_preload::handle(
            &mut cache_guard,
            &task,
            resolved_path.as_deref(),
            ctx.crp_mode,
        );

        // Active Inference: predict which provider data will be needed and
        // prefetch it into the session cache for fast subsequent access.
        let provider_hints = predict_and_prefetch(&task, &mut cache_guard);
        if !provider_hints.is_empty() {
            result.push_str(&provider_hints);
        }

        drop(cache_guard);

        if let Some(ref session_lock) = ctx.session {
            if let Some(mut session_guard) =
                crate::server::bounded_lock::write(session_lock, "ctx_preload:session_write")
            {
                if session_guard.active_structured_intent.is_none()
                    || session_guard
                        .active_structured_intent
                        .as_ref()
                        .is_none_or(|i| i.confidence < 0.6)
                {
                    session_guard.set_task(&task, Some("preload"));
                }
            }

            if let Some(session_guard) =
                crate::server::bounded_lock::read(session_lock, "ctx_preload:session_read")
            {
                if let Some(ref intent) = session_guard.active_structured_intent {
                    if let Some(ref ledger_lock) = ctx.ledger {
                        let Some(ledger) =
                            crate::server::bounded_lock::read(ledger_lock, "ctx_preload:ledger")
                        else {
                            return Ok(ToolOutput::simple(result));
                        };
                        if !ledger.entries.is_empty() {
                            let known: Vec<String> = session_guard
                                .files_touched
                                .iter()
                                .map(|f| f.path.clone())
                                .collect();
                            let deficit = crate::core::context_deficit::detect_deficit(
                                &ledger, intent, &known,
                            );
                            if !deficit.suggested_files.is_empty() {
                                result.push_str("\n\n--- SUGGESTED FILES ---");
                                for s in &deficit.suggested_files {
                                    result.push_str(&format!(
                                        "\n  {} ({:?}, ~{} tok, mode: {})",
                                        s.path, s.reason, s.estimated_tokens, s.recommended_mode
                                    ));
                                }
                            }

                            let pressure = ledger.pressure();
                            if pressure.utilization > 0.7 {
                                let plan = ledger.reinjection_plan(intent, 0.6);
                                if !plan.actions.is_empty() {
                                    result.push_str("\n\n--- REINJECTION PLAN ---");
                                    result.push_str(&format!(
                                        "\n  Context pressure: {:.0}% -> target: 60%",
                                        pressure.utilization * 100.0
                                    ));
                                    for a in &plan.actions {
                                        result.push_str(&format!(
                                            "\n  {} : {} -> {} (frees ~{} tokens)",
                                            a.path, a.current_mode, a.new_mode, a.tokens_freed
                                        ));
                                    }
                                    result.push_str(&format!(
                                        "\n  Total freeable: {} tokens",
                                        plan.total_tokens_freed
                                    ));
                                }
                            }
                        }
                    }
                }
            }
        }

        Ok(ToolOutput {
            text: result,
            original_tokens: 0,
            saved_tokens: 0,
            mode: Some("preload".to_string()),
            path: None,
            changed: false,
        })
    }
}

/// Use Active Inference to predict useful provider data and prefetch it.
/// Returns a summary string to append to the preload output, or empty if
/// no providers are available or predictions are empty.
fn predict_and_prefetch(task: &str, cache: &mut crate::core::cache::SessionCache) -> String {
    crate::core::providers::init::init_builtin_providers();
    let registry = crate::core::providers::registry::global_registry();
    let available = registry.available_provider_ids();
    if available.is_empty() {
        return String::new();
    }

    let mut bandit = crate::core::provider_bandit::ProviderBandit::new();
    let predictions =
        crate::core::active_inference::predict_preloads(task, &available, &mut bandit, 2);

    if predictions.is_empty() {
        return String::new();
    }

    let mut out = String::from("\n\n--- PROVIDER PRELOAD ---");
    let mut prefetched = 0usize;

    for pred in &predictions {
        let params = crate::core::providers::provider_trait::ProviderParams {
            limit: Some(5),
            ..Default::default()
        };

        match registry.execute_as_chunks(&pred.provider_id, &pred.action, &params) {
            Ok(chunks) => {
                let artifacts = crate::core::consolidation::consolidate(&chunks);
                for entry in &artifacts.cache_entries {
                    cache.store(&entry.uri, &entry.content);
                    prefetched += 1;
                }
                out.push_str(&format!(
                    "\n  {} {} → {} items cached (confidence: {:.0}%)",
                    pred.provider_id,
                    pred.action,
                    chunks.len(),
                    pred.confidence * 100.0,
                ));
            }
            Err(e) => {
                tracing::debug!(
                    "[preload] provider {}/{} failed: {e}",
                    pred.provider_id,
                    pred.action,
                );
            }
        }
    }

    if prefetched == 0 {
        return String::new();
    }

    out
}