chore: simplify codex prompt handling

packages/ai/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Changed
+
+- OpenAI Codex responses now use the context system prompt directly in the instructions field.
+
 ### Fixed
 
 - Fixed orphaned tool results after errored assistant messages causing Codex API errors. When an assistant message has `stopReason: "error"`, its tool calls are now excluded from pending tool tracking, preventing synthetic tool results from being generated for calls that will be dropped by provider-specific converters. ([#812](https://github.com/badlogic/pi-mono/issues/812))

packages/ai/src/constants.ts

@@ -1,13 +0,0 @@
-/**
- * Static Pi instructions for OpenAI Codex.
- * This string is whitelisted by OpenAI and must not change.
- */
-export const PI_STATIC_INSTRUCTIONS = `You are pi, an expert coding assistant. You help users with coding tasks by reading files, executing commands, editing code, and writing new files.
-
-Pi specific Documentation:
-- Main documentation: pi-internal://README.md
-- Additional docs: pi-internal://docs
-- Examples: pi-internal://examples (extensions, custom tools, SDK)
-- When asked to create: custom models/providers (README.md), extensions (docs/extensions.md, examples/extensions/), themes (docs/theme.md), skills (docs/skills.md), TUI components (docs/tui.md - has copy-paste patterns)
-- Always read the doc, examples, AND follow .md cross-references before implementing
-`;

packages/ai/src/index.ts

@@ -1,4 +1,3 @@
-export * from "./constants.js";
 export * from "./models.js";
 export * from "./providers/anthropic.js";
 export * from "./providers/google.js";

packages/ai/src/providers/openai-codex-responses.ts

@@ -4,7 +4,6 @@ import type {
 	ResponseOutputMessage,
 	ResponseReasoningItem,
 } from "openai/resources/responses/responses.js";
-import { PI_STATIC_INSTRUCTIONS } from "../constants.js";
 import { calculateCost } from "../models.js";
 import { getEnvApiKey } from "../stream.js";
 import type {
@@ -215,22 +214,14 @@ function buildRequestBody(
 	context: Context,
 	options?: OpenAICodexResponsesOptions,
 ): RequestBody {
-	const systemPrompt = buildSystemPrompt(context.systemPrompt);
 	const messages = convertMessages(model, context);
 
-	// Prepend developer messages
-	const developerMessages = systemPrompt.developerMessages.map((text) => ({
-		type: "message",
-		role: "developer",
-		content: [{ type: "input_text", text }],
-	}));
-
 	const body: RequestBody = {
 		model: model.id,
 		store: false,
 		stream: true,
-		instructions: systemPrompt.instructions,
+		instructions: context.systemPrompt,
-		input: [...developerMessages, ...messages],
+		input: messages,
 		text: { verbosity: options?.textVerbosity || "medium" },
 		include: ["reasoning.encrypted_content"],
 		prompt_cache_key: options?.sessionId,
@@ -262,23 +253,6 @@ function buildRequestBody(
 	return body;
 }
 
-function buildSystemPrompt(userSystemPrompt?: string): { instructions: string; developerMessages: string[] } {
-	// PI_STATIC_INSTRUCTIONS is whitelisted and must be in the instructions field.
-	// User's system prompt goes in developer messages, with the static prefix stripped.
-	const staticPrefix = PI_STATIC_INSTRUCTIONS.trim();
-	const developerMessages: string[] = [];
-
-	if (userSystemPrompt?.trim()) {
-		let dynamicPart = userSystemPrompt.trim();
-		if (dynamicPart.startsWith(staticPrefix)) {
-			dynamicPart = dynamicPart.slice(staticPrefix.length).trim();
-		}
-		if (dynamicPart) developerMessages.push(dynamicPart);
-	}
-
-	return { instructions: staticPrefix, developerMessages };
-}
-
 function clampReasoningEffort(modelId: string, effort: string): string {
 	const id = modelId.includes("/") ? modelId.split("/").pop()! : modelId;
 	if (id.startsWith("gpt-5.2") && effort === "minimal") return "low";

packages/coding-agent/CHANGELOG.md

@@ -10,10 +10,18 @@
 - Added `ctx.compact()` and `ctx.getContextUsage()` to extension contexts for programmatic compaction and context usage checks.
 - Added documentation for delete word forward and kill ring keybindings in interactive mode. ([#810](https://github.com/badlogic/pi-mono/pull/810) by [@Perlence](https://github.com/Perlence))
 
+### Changed
+
+- Updated the default system prompt wording to clarify the pi harness and documentation scope.
+
 ### Fixed
 
 - Fixed photon module failing to load in ESM context with "require is not defined" error ([#795](https://github.com/badlogic/pi-mono/pull/795) by [@dannote](https://github.com/dannote))
 
+### Removed
+
+- Removed `pi-internal://` path resolution from the read tool.
+
 ## [0.48.0] - 2026-01-16
 
 ### Added

packages/coding-agent/src/core/system-prompt.ts

@@ -2,11 +2,10 @@
  * System prompt construction and project context loading
  */
 
-import { PI_STATIC_INSTRUCTIONS } from "@mariozechner/pi-ai";
 import chalk from "chalk";
 import { existsSync, readFileSync } from "fs";
 import { join, resolve } from "path";
-import { getAgentDir, getReadmePath } from "../config.js";
+import { getAgentDir, getDocsPath, getExamplesPath, getReadmePath } from "../config.js";
 import type { SkillsSettings } from "./settings-manager.js";
 import { formatSkillsForPrompt, loadSkills, type Skill } from "./skills.js";
 import type { ToolName } from "./tools/index.js";
@@ -136,17 +135,6 @@ export interface BuildSystemPromptOptions {
 	skills?: Skill[];
 }
 
-/**
- * Get the Pi installation path for documentation references.
- * This resolves the pi-internal:// scheme used in the static instructions.
- */
-function getPiPath(): string {
-	// getReadmePath returns something like /path/to/pi/README.md
-	// We want the parent directory
-	const readmePath = getReadmePath();
-	return resolve(readmePath, "..");
-}
-
 /** Build the system prompt with tools, guidelines, and context */
 export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): string {
 	const {
@@ -185,7 +173,6 @@ export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): strin
 		providedSkills ??
 		(skillsSettings?.enabled !== false ? loadSkills({ ...skillsSettings, cwd: resolvedCwd, agentDir }).skills : []);
 
-	// Handle custom prompt (full replacement)
 	if (resolvedCustomPrompt) {
 		let prompt = resolvedCustomPrompt;
 
@@ -196,7 +183,7 @@ export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): strin
 		// Append project context files
 		if (contextFiles.length > 0) {
 			prompt += "\n\n# Project Context\n\n";
-			prompt += "The following project context files have been loaded:\n\n";
+			prompt += "Project-specific instructions and guidelines:\n\n";
 			for (const { path: filePath, content } of contextFiles) {
 				prompt += `## ${filePath}\n\n${content}\n\n`;
 			}
@@ -215,6 +202,11 @@ export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): strin
 		return prompt;
 	}
 
+	// Get absolute paths to documentation and examples
+	const readmePath = getReadmePath();
+	const docsPath = getDocsPath();
+	const examplesPath = getExamplesPath();
+
 	// Build tools list based on selected tools
 	const tools = selectedTools || (["read", "bash", "edit", "write"] as ToolName[]);
 	const toolsList = tools.length > 0 ? tools.map((t) => `- ${t}: ${toolDescriptions[t]}`).join("\n") : "(none)";
@@ -272,12 +264,7 @@ export function buildSystemPrompt(options: BuildSystemPromptOptions = {}): strin
 
 	const guidelines = guidelinesList.map((g) => `- ${g}`).join("\n");
 
-	// Build prompt with static prefix + dynamic parts
+	let prompt = `You are an expert coding assistant operating inside pi, a coding agent harness. You help users by reading files, executing commands, editing code, and writing new files.
-	const piPath = getPiPath();
-
-	let prompt = `${PI_STATIC_INSTRUCTIONS}
-Pi path:
-pi-internal:// refers to paths in ${piPath}
 
 Available tools:
 ${toolsList}
@@ -285,7 +272,14 @@ ${toolsList}
 In addition to the tools above, you may have access to other custom tools depending on the project.
 
 Guidelines:
-${guidelines}`;
+${guidelines}
+
+Pi documentation (only when the user asks about pi itself, its SDK, extensions, themes, skills, or TUI):
+- Main documentation: ${readmePath}
+- Additional docs: ${docsPath}
+- Examples: ${examplesPath} (extensions, custom tools, SDK)
+- When asked to create: custom models/providers (README.md), extensions (docs/extensions.md, examples/extensions/), themes (docs/theme.md), skills (docs/skills.md), TUI components (docs/tui.md - has copy-paste patterns)
+- When working on pi topics, read the docs and examples, and follow .md cross-references before implementing`;
 
 	if (appendSection) {
 		prompt += appendSection;
@@ -294,7 +288,7 @@ ${guidelines}`;
 	// Append project context files
 	if (contextFiles.length > 0) {
 		prompt += "\n\n# Project Context\n\n";
-		prompt += "The following project context files have been loaded:\n\n";
+		prompt += "Project-specific instructions and guidelines:\n\n";
 		for (const { path: filePath, content } of contextFiles) {
 			prompt += `## ${filePath}\n\n${content}\n\n`;
 		}

packages/coding-agent/src/core/tools/path-utils.ts

@@ -1,12 +1,9 @@
 import { accessSync, constants } from "node:fs";
 import * as os from "node:os";
 import { isAbsolute, resolve as resolvePath } from "node:path";
-import { getPackageDir } from "../../config.js";
 
 const UNICODE_SPACES = /[\u00A0\u2000-\u200A\u202F\u205F\u3000]/g;
 const NARROW_NO_BREAK_SPACE = "\u202F";
-export const PI_INTERNAL_SCHEME = "pi-internal://";
-
 function normalizeUnicodeSpaces(str: string): string {
 	return str.replace(UNICODE_SPACES, " ");
 }
@@ -48,12 +45,6 @@ export function resolveToCwd(filePath: string, cwd: string): string {
 }
 
 export function resolveReadPath(filePath: string, cwd: string): string {
-	// Handle pi-internal:// scheme for Pi package documentation
-	if (filePath.startsWith(PI_INTERNAL_SCHEME)) {
-		const relativePath = filePath.slice(PI_INTERNAL_SCHEME.length);
-		return resolvePath(getPackageDir(), relativePath);
-	}
-
 	const resolved = resolveToCwd(filePath, cwd);
 
 	if (fileExists(resolved)) {

packages/coding-agent/src/core/tools/read.ts

@@ -5,7 +5,7 @@ import { constants } from "fs";
 import { access as fsAccess, readFile as fsReadFile } from "fs/promises";
 import { formatDimensionNote, resizeImage } from "../../utils/image-resize.js";
 import { detectSupportedImageMimeTypeFromFile } from "../../utils/mime.js";
-import { PI_INTERNAL_SCHEME, resolveReadPath } from "./path-utils.js";
+import { resolveReadPath } from "./path-utils.js";
 import { DEFAULT_MAX_BYTES, DEFAULT_MAX_LINES, formatSize, type TruncationResult, truncateHead } from "./truncate.js";
 
 const readSchema = Type.Object({
@@ -111,19 +111,13 @@ export function createReadTool(cwd: string, options?: ReadToolOptions): AgentToo
 									if (dimensionNote) {
 										textNote += `\n${dimensionNote}`;
 									}
-									if (path.startsWith(PI_INTERNAL_SCHEME)) {
-										textNote += `\n[${path} -> ${absolutePath}. Use filesystem paths for further reads.]`;
-									}
 
 									content = [
 										{ type: "text", text: textNote },
 										{ type: "image", data: resized.data, mimeType: resized.mimeType },
 									];
 								} else {
-									let textNote = `Read image file [${mimeType}]`;
+									const textNote = `Read image file [${mimeType}]`;
-									if (path.startsWith(PI_INTERNAL_SCHEME)) {
-										textNote += `\n[${path} -> ${absolutePath}. Use filesystem paths for further reads.]`;
-									}
 									content = [
 										{ type: "text", text: textNote },
 										{ type: "image", data: base64, mimeType },
@@ -191,11 +185,6 @@ export function createReadTool(cwd: string, options?: ReadToolOptions): AgentToo
 									outputText = truncation.content;
 								}
 
-								// Add filesystem path hint for pi-internal:// paths
-								if (path.startsWith(PI_INTERNAL_SCHEME)) {
-									outputText += `\n\n[${path} -> ${absolutePath}. Use filesystem paths for further reads.]`;
-								}
-
 								content = [{ type: "text", text: outputText }];
 							}