feat: integrate synthetic instruction injection into all fetch handlers

- Add Gemini and OpenAI Responses API format support to synth-instruction.ts
- Integrate injectSynthInstruction and injectNudge into all three fetch handlers
- Add SynthPrompts interface and toolTracker context to FetchWrapperContext
- Wire up toolTracker and prompt loading in index.ts

Author: Tarquinen

index.ts

@@ -7,6 +7,8 @@ import { createPluginState } from "./lib/state"
 import { installFetchWrapper } from "./lib/fetch-wrapper"
 import { createPruningTool } from "./lib/pruning-tool"
 import { createEventHandler, createChatParamsHandler } from "./lib/hooks"
+import { createToolTracker } from "./lib/synth-instruction"
+import { loadPrompt } from "./lib/prompt"
 
 const plugin: Plugin = (async (ctx) => {
     const { config, migrations } = getConfig(ctx)
@@ -39,8 +41,15 @@ const plugin: Plugin = (async (ctx) => {
         ctx.directory
     )
 
-    // Install global fetch wrapper for context pruning
-    installFetchWrapper(state, logger, ctx.client)
+    // Create tool tracker and load prompts for synthetic instruction injection
+    const toolTracker = createToolTracker()
+    const prompts = {
+        synthInstruction: loadPrompt("synthetic"),
+        nudgeInstruction: loadPrompt("nudge")
+    }
+
+    // Install global fetch wrapper for context pruning and synthetic instruction injection
+    installFetchWrapper(state, logger, ctx.client, config, toolTracker, prompts)
 
     // Log initialization
     logger.info("plugin", "DCP initialized", {

lib/fetch-wrapper/gemini.ts

@@ -4,6 +4,7 @@ import {
     getAllPrunedIds,
     fetchSessionMessages
 } from "./types"
+import { injectNudgeGemini, injectSynthGemini } from "../synth-instruction"
 
 /**
  * Handles Google/Gemini format (body.contents array with functionResponse parts).
@@ -18,20 +19,39 @@ export async function handleGemini(
         return { modified: false, body }
     }
 
+    let modified = false
+
+    // Inject synthetic instructions if onTool strategies are enabled
+    if (ctx.config.strategies.onTool.length > 0) {
+        // Inject periodic nudge based on tool result count
+        if (ctx.config.nudge_freq > 0) {
+            if (injectNudgeGemini(body.contents, ctx.toolTracker, ctx.prompts.nudgeInstruction, ctx.config.nudge_freq)) {
+                ctx.logger.info("fetch", "Injected nudge instruction (Gemini)")
+                modified = true
+            }
+        }
+
+        // Inject synthetic instruction into last user content
+        if (injectSynthGemini(body.contents, ctx.prompts.synthInstruction)) {
+            ctx.logger.info("fetch", "Injected synthetic instruction (Gemini)")
+            modified = true
+        }
+    }
+
     // Check for functionResponse parts in any content item
     const hasFunctionResponses = body.contents.some((content: any) =>
         Array.isArray(content.parts) &&
         content.parts.some((part: any) => part.functionResponse)
     )
 
     if (!hasFunctionResponses) {
-        return { modified: false, body }
+        return { modified, body }
     }
 
     const { allSessions, allPrunedIds } = await getAllPrunedIds(ctx.client, ctx.state)
 
     if (allPrunedIds.size === 0) {
-        return { modified: false, body }
+        return { modified, body }
     }
 
     // Find the active session to get the position mapping
@@ -48,7 +68,7 @@ export async function handleGemini(
 
     if (!positionMapping) {
         ctx.logger.info("fetch", "No Google tool call mapping found, skipping pruning for Gemini format")
-        return { modified: false, body }
+        return { modified, body }
     }
 
     // Build position counters to track occurrence of each tool name
@@ -130,5 +150,5 @@ export async function handleGemini(
         return { modified: true, body }
     }
 
-    return { modified: false, body }
+    return { modified, body }
 }

lib/fetch-wrapper/index.ts

@@ -1,11 +1,13 @@
 import type { PluginState } from "../state"
 import type { Logger } from "../logger"
-import type { FetchHandlerContext } from "./types"
+import type { FetchHandlerContext, SynthPrompts } from "./types"
+import type { ToolTracker } from "../synth-instruction"
+import type { PluginConfig } from "../config"
 import { handleOpenAIChatAndAnthropic } from "./openai-chat"
 import { handleGemini } from "./gemini"
 import { handleOpenAIResponses } from "./openai-responses"
 
-export type { FetchHandlerContext, FetchHandlerResult } from "./types"
+export type { FetchHandlerContext, FetchHandlerResult, SynthPrompts } from "./types"
 
 /**
  * Creates a wrapped global fetch that intercepts API calls and performs
@@ -20,14 +22,20 @@ export type { FetchHandlerContext, FetchHandlerResult } from "./types"
 export function installFetchWrapper(
     state: PluginState,
     logger: Logger,
-    client: any
+    client: any,
+    config: PluginConfig,
+    toolTracker: ToolTracker,
+    prompts: SynthPrompts
 ): () => void {
     const originalGlobalFetch = globalThis.fetch
 
     const ctx: FetchHandlerContext = {
         state,
         logger,
-        client
+        client,
+        config,
+        toolTracker,
+        prompts
     }
 
     globalThis.fetch = async (input: any, init?: any) => {

lib/fetch-wrapper/openai-chat.ts

@@ -6,6 +6,7 @@ import {
     getMostRecentActiveSession
 } from "./types"
 import { cacheToolParametersFromMessages } from "../tool-cache"
+import { injectNudge, injectSynth } from "../synth-instruction"
 
 /**
  * Handles OpenAI Chat Completions format (body.messages with role='tool').
@@ -23,6 +24,25 @@ export async function handleOpenAIChatAndAnthropic(
     // Cache tool parameters from messages
     cacheToolParametersFromMessages(body.messages, ctx.state)
 
+    let modified = false
+
+    // Inject synthetic instructions if onTool strategies are enabled
+    if (ctx.config.strategies.onTool.length > 0) {
+        // Inject periodic nudge based on tool result count
+        if (ctx.config.nudge_freq > 0) {
+            if (injectNudge(body.messages, ctx.toolTracker, ctx.prompts.nudgeInstruction, ctx.config.nudge_freq)) {
+                ctx.logger.info("fetch", "Injected nudge instruction")
+                modified = true
+            }
+        }
+
+        // Inject synthetic instruction into last user message
+        if (injectSynth(body.messages, ctx.prompts.synthInstruction)) {
+            ctx.logger.info("fetch", "Injected synthetic instruction")
+            modified = true
+        }
+    }
+
     // Check for tool messages in both formats:
     // 1. OpenAI style: role === 'tool'
     // 2. Anthropic style: role === 'user' with content containing tool_result
@@ -39,7 +59,7 @@ export async function handleOpenAIChatAndAnthropic(
     const { allSessions, allPrunedIds } = await getAllPrunedIds(ctx.client, ctx.state)
 
     if (toolMessages.length === 0 || allPrunedIds.size === 0) {
-        return { modified: false, body }
+        return { modified, body }
     }
 
     let replacedCount = 0
@@ -103,5 +123,5 @@ export async function handleOpenAIChatAndAnthropic(
         return { modified: true, body }
     }
 
-    return { modified: false, body }
+    return { modified, body }
 }

lib/fetch-wrapper/openai-responses.ts

@@ -6,6 +6,7 @@ import {
     getMostRecentActiveSession
 } from "./types"
 import { cacheToolParametersFromInput } from "../tool-cache"
+import { injectNudgeResponses, injectSynthResponses } from "../synth-instruction"
 
 /**
  * Handles OpenAI Responses API format (body.input array with function_call_output items).
@@ -23,17 +24,36 @@ export async function handleOpenAIResponses(
     // Cache tool parameters from input
     cacheToolParametersFromInput(body.input, ctx.state)
 
+    let modified = false
+
+    // Inject synthetic instructions if onTool strategies are enabled
+    if (ctx.config.strategies.onTool.length > 0) {
+        // Inject periodic nudge based on tool result count
+        if (ctx.config.nudge_freq > 0) {
+            if (injectNudgeResponses(body.input, ctx.toolTracker, ctx.prompts.nudgeInstruction, ctx.config.nudge_freq)) {
+                ctx.logger.info("fetch", "Injected nudge instruction (Responses API)")
+                modified = true
+            }
+        }
+
+        // Inject synthetic instruction into last user message
+        if (injectSynthResponses(body.input, ctx.prompts.synthInstruction)) {
+            ctx.logger.info("fetch", "Injected synthetic instruction (Responses API)")
+            modified = true
+        }
+    }
+
     // Check for function_call_output items
     const functionOutputs = body.input.filter((item: any) => item.type === 'function_call_output')
 
     if (functionOutputs.length === 0) {
-        return { modified: false, body }
+        return { modified, body }
     }
 
     const { allSessions, allPrunedIds } = await getAllPrunedIds(ctx.client, ctx.state)
 
     if (allPrunedIds.size === 0) {
-        return { modified: false, body }
+        return { modified, body }
     }
 
     let replacedCount = 0
@@ -77,5 +97,5 @@ export async function handleOpenAIResponses(
         return { modified: true, body }
     }
 
-    return { modified: false, body }
+    return { modified, body }
 }

lib/fetch-wrapper/types.ts

@@ -1,14 +1,25 @@
 import type { PluginState } from "../state"
 import type { Logger } from "../logger"
+import type { ToolTracker } from "../synth-instruction"
+import type { PluginConfig } from "../config"
 
 /** The message used to replace pruned tool output content */
 export const PRUNED_CONTENT_MESSAGE = '[Output removed to save context - information superseded or no longer needed]'
 
+/** Prompts used for synthetic instruction injection */
+export interface SynthPrompts {
+    synthInstruction: string
+    nudgeInstruction: string
+}
+
 /** Context passed to each format-specific handler */
 export interface FetchHandlerContext {
     state: PluginState
     logger: Logger
     client: any
+    config: PluginConfig
+    toolTracker: ToolTracker
+    prompts: SynthPrompts
 }
 
 /** Result from a format handler indicating what happened */

lib/pruning-tool.ts

@@ -71,7 +71,7 @@ export function createPruningTool(janitor: Janitor, config: PluginConfig): Retur
                 return "No prunable tool outputs found. Context is already optimized.\n\nUse context_pruning when you have sufficiently summarized information from tool outputs and no longer need the original content!"
             }
 
-            return janitor.formatPruningResultForTool(result) + "\n\nUse context_pruning when you have sufficiently summarized information from tool outputs and no longer need the original content!"
+            return janitor.formatPruningResultForTool(result) + "\n\nKeep using context_pruning when you have sufficiently summarized information from tool outputs and no longer need the original content!"
         },
     })
 }