Add context_pruning tool and refactor to strategies-based config

.gitignore

@@ -30,3 +30,6 @@ Thumbs.db
 
 # Tests (local development only)
 tests/
+
+# Development notes
+notes/

README.md

@@ -78,7 +78,7 @@ If you want to ensure a specific version is always used or update your version,
 ```json
 {
   "plugin": [
-    "@tarquinen/[email protected].14"
+    "@tarquinen/[email protected].15"
   ]
 }
 ```

index.ts

@@ -1,5 +1,6 @@
 // index.ts - Main plugin entry point for Dynamic Context Pruning
 import type { Plugin } from "@opencode-ai/plugin"
+import { tool } from "@opencode-ai/plugin"
 import { getConfig } from "./lib/config"
 import { Logger } from "./lib/logger"
 import { Janitor, type SessionStats } from "./lib/janitor"
@@ -20,7 +21,7 @@ async function isSubagentSession(client: any, sessionID: string): Promise<boolea
 }
 
 const plugin: Plugin = (async (ctx) => {
-    const config = getConfig(ctx)
+    const { config, migrations } = getConfig(ctx)
 
     // Exit early if plugin is disabled
     if (!config.enabled) {
@@ -38,7 +39,7 @@ const plugin: Plugin = (async (ctx) => {
     const statsState = new Map<string, SessionStats>()
     const toolParametersCache = new Map<string, any>() // callID -> parameters
     const modelCache = new Map<string, { providerID: string; modelID: string }>() // sessionID -> model info
-    const janitor = new Janitor(ctx.client, prunedIdsState, statsState, logger, toolParametersCache, config.protectedTools, modelCache, config.model, config.showModelErrorToasts, config.pruningMode, config.pruning_summary, ctx.directory)
+    const janitor = new Janitor(ctx.client, prunedIdsState, statsState, logger, toolParametersCache, config.protectedTools, modelCache, config.model, config.showModelErrorToasts, config.pruning_summary, ctx.directory)
 
     const cacheToolParameters = (messages: any[]) => {
         for (const message of messages) {
@@ -142,13 +143,31 @@ const plugin: Plugin = (async (ctx) => {
     }
 
     logger.info("plugin", "DCP initialized", {
-        mode: config.pruningMode,
+        strategies: config.strategies,
         model: config.model || "auto"
     })
 
     // Check for updates on launch (fire and forget)
     checkForUpdates(ctx.client, logger).catch(() => {})
 
+    // Show migration toast if config was migrated (delayed to not overlap with version toast)
+    if (migrations.length > 0) {
+        setTimeout(async () => {
+            try {
+                await ctx.client.tui.showToast({
+                    body: {
+                        title: "DCP: Config upgraded",
+                        message: migrations.join('\n'),
+                        variant: "info",
+                        duration: 8000
+                    }
+                })
+            } catch {
+                // Silently fail - toast is non-critical
+            }
+        }, 7000) // 7s delay to show after version toast (6s) completes
+    }
+
     return {
         /**
          * Event Hook: Triggers janitor analysis when session becomes idle
@@ -158,8 +177,11 @@ const plugin: Plugin = (async (ctx) => {
                 // Skip pruning for subagent sessions
                 if (await isSubagentSession(ctx.client, event.properties.sessionID)) return
 
+                // Skip if no idle strategies configured
+                if (config.strategies.onIdle.length === 0) return
+
                 // Fire and forget the janitor - don't block the event handler
-                janitor.run(event.properties.sessionID).catch(err => {
+                janitor.runOnIdle(event.properties.sessionID, config.strategies.onIdle).catch(err => {
                     logger.error("janitor", "Failed", { error: err.message })
                 })
             }
@@ -168,7 +190,7 @@ const plugin: Plugin = (async (ctx) => {
         /**
          * Chat Params Hook: Caches model info for janitor
          */
-        "chat.params": async (input, output) => {
+        "chat.params": async (input, _output) => {
             const sessionId = input.sessionID
 
             // Cache model information for this session so janitor can access it
@@ -188,6 +210,63 @@ const plugin: Plugin = (async (ctx) => {
                 })
             }
         },
+
+        /**
+         * Tool Hook: Exposes context_pruning tool to AI (if configured)
+         */
+        tool: config.strategies.onTool.length > 0 ? {
+            context_pruning: tool({
+                description: `Performs semantic pruning on session tool outputs that are no longer relevant to the current task. Use this to declutter the conversation context and filter signal from noise when you notice the context is getting cluttered with outdated information.
+
+## When to Use This Tool
+
+- After completing a debugging session or fixing a bug
+- When switching focus to a new task or feature
+- After exploring multiple files that didn't lead to changes
+- When you've been iterating on a difficult problem and some approaches didn't pan out
+- When old file reads, greps, or bash outputs are no longer relevant
+
+## Examples
+
+<example>
+Working through a list of bugs to fix:
+User: Please fix these 5 type errors in the codebase.
+Assistant: I'll work through each error. [Fixes first error]
+First error fixed. Let me prune the debugging context before moving to the next one.
+[Uses context_pruning with reason: "first bug fixed, moving to next task"]
+</example>
+
+<example>
+After exploring the codebase to understand it:
+Assistant: I've reviewed the relevant files. Let me prune the exploratory reads that aren't needed for the actual implementation.
+[Uses context_pruning with reason: "exploration complete, pruning unrelated file reads"]
+</example>
+
+<example>
+After trying multiple approaches that didn't work:
+Assistant: I've been trying several approaches to fix this issue. Let me prune the failed attempts to keep focus on the working solution.
+[Uses context_pruning with reason: "pruning failed iteration attempts, keeping working solution context"]
+</example>`,
+                args: {
+                    reason: tool.schema.string().optional().describe(
+                        "Brief reason for triggering pruning (e.g., 'task complete', 'switching focus')"
+                    ),
+                },
+                async execute(args, ctx) {
+                    const result = await janitor.runForTool(
+                        ctx.sessionID,
+                        config.strategies.onTool,
+                        args.reason
+                    )
+
+                    if (!result || result.prunedCount === 0) {
+                        return "No prunable tool outputs found. Context is already optimized."
+                    }
+
+                    return janitor.formatPruningResultForTool(result)
+                },
+            }),
+        } : undefined,
     }
 }) satisfies Plugin