feat(prompt): implement prompt injection slice 2

This commit is contained in:
2026-06-11 17:27:31 +02:00
parent 56560d9d56
commit 621434b6e8
5 changed files with 352 additions and 4 deletions
+7 -4
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@@ -11,6 +11,8 @@ import {
buildPreInitHint,
modeAllowsPreInitHint,
modeAllowsInjection,
discoverContextWindow,
buildInjectionPayload,
} from "./src/index.js";
import { loadConfig } from "./src/config.js";
import { createLLMClient } from "./src/llm/llm-client.js";
@@ -367,17 +369,18 @@ export default function (pi: ExtensionAPI) {
}
// Maps exist but advisory mode does not permit automatic artifact injection yet.
// Full root-pair injection with canonical markers comes in later slices.
if (!modeAllowsInjection(config.promptInjectionMode)) {
return {};
}
// Slice 2: post-init root-pair preload + budgeted expansion
const contextWindow = discoverContextWindow(_ctx);
const payload = buildInjectionPayload(_ctx.cwd, config, contextWindow);
return {
message: {
customType: "pi-project-map-hint",
content:
"📋 Project map active: Start with the root `.pi-map.index.md`, use indexes first for routing, read the local `.pi-map.md` plus source before edits, run `project_map_patch` after source edits, and run `project_map_validate` before freshness-sensitive architectural handoff.",
display: false,
content: payload.content,
display: payload.display,
},
};
});
+4
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@@ -31,6 +31,10 @@ export {
modeAllowsPreInitHint,
modeAllowsInjection,
modeRequiresProtocolPath,
discoverContextWindow,
estimateTokens,
findAllArtifactPairs,
buildInjectionPayload,
ROOT_PAIR_START_MARKER,
ROOT_PAIR_END_MARKER,
TRUST_BOUNDARY_TEXT,
+178
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@@ -1,3 +1,5 @@
import { readdirSync, statSync, readFileSync } from "fs";
import { join, relative } from "path";
import type { SkillConfig, PromptInjectionMode } from "./config.js";
/**
@@ -92,3 +94,179 @@ export function modeAllowsInjection(mode: PromptInjectionMode): boolean {
export function modeRequiresProtocolPath(mode: PromptInjectionMode): boolean {
return mode === "strict";
}
// ---------------------------------------------------------------------------
// Context-window discovery (Slice 2)
// ---------------------------------------------------------------------------
const KNOWN_MODEL_CONTEXT_WINDOWS: Record<string, number> = {
"gpt-4o": 128_000,
"gpt-4o-mini": 128_000,
"gpt-4-turbo": 128_000,
"gpt-4": 8_192,
"claude-3-5-sonnet": 200_000,
"claude-3-opus": 200_000,
"kimi-for-coding": 200_000,
k2p6: 1_000_000,
"kimi-k2-thinking": 256_000,
};
/**
* Discover the active model's context-window size from Pi runtime metadata.
* Returns `undefined` when unavailable so callers fall back to the absolute cap.
*/
export function discoverContextWindow(ctx: any): number | undefined {
const model = ctx?.model;
if (model) {
if (typeof model.contextWindow === "number" && model.contextWindow > 0) {
return model.contextWindow;
}
if (
typeof model.maxContextTokens === "number" &&
model.maxContextTokens > 0
) {
return model.maxContextTokens;
}
if (typeof model.id === "string") {
const known = KNOWN_MODEL_CONTEXT_WINDOWS[model.id];
if (known) return known;
}
}
return undefined;
}
// ---------------------------------------------------------------------------
// Token estimation (best-effort, deterministic)
// ---------------------------------------------------------------------------
/**
* Rough token estimate from character count.
* 1 token ≈ 4 chars for English/prose is a conservative heuristic.
*/
export function estimateTokens(text: string): number {
return Math.ceil(text.length / 4);
}
// ---------------------------------------------------------------------------
// Artifact-pair discovery
// ---------------------------------------------------------------------------
export interface ArtifactPair {
dir: string;
mapPath: string;
indexPath: string;
}
/**
* Find every directory under `cwd` that contains both `.pi-map.md` and
* `.pi-map.index.md`. Returns shallowest directories first for predictable
* structural coverage.
*/
export function findAllArtifactPairs(cwd: string): ArtifactPair[] {
const results: ArtifactPair[] = [];
function walk(dir: string) {
let entries: import("fs").Dirent[];
try {
entries = readdirSync(dir, { withFileTypes: true });
} catch {
return;
}
for (const entry of entries) {
if (
entry.isDirectory() &&
!entry.name.startsWith(".") &&
entry.name !== "node_modules"
) {
walk(join(dir, entry.name));
}
}
const mapPath = join(dir, ".pi-map.md");
const indexPath = join(dir, ".pi-map.index.md");
try {
statSync(mapPath);
statSync(indexPath);
results.push({
dir: relative(cwd, dir) || ".",
mapPath: relative(cwd, mapPath),
indexPath: relative(cwd, indexPath),
});
} catch {
// skip dirs without the paired artifacts
}
}
walk(cwd);
// shallow-first: sort by path depth then alphabetically
results.sort((a, b) => {
const depthA = a.dir.split(/[/\\]/).length;
const depthB = b.dir.split(/[/\\]/).length;
if (depthA !== depthB) return depthA - depthB;
return a.dir.localeCompare(b.dir);
});
return results;
}
// ---------------------------------------------------------------------------
// Budgeted expansion
// ---------------------------------------------------------------------------
/**
* Build the full injection payload for a project that already has artifacts.
*
* Guarantees:
* 1. Root pair is always present first.
* 2. Additional pairs are appended shallow-first while the budget allows.
* 3. A brief maintenance reminder is prepended.
*/
export function buildInjectionPayload(
cwd: string,
config: Pick<SkillConfig, "contextBudgetPercent" | "contextBudgetMaxTokens">,
contextWindow: number | undefined,
): { content: string; display: false } {
const budget = computeInjectionBudget(config, contextWindow);
const pairs = findAllArtifactPairs(cwd);
const rootIndex = pairs.findIndex((p) => p.dir === ".");
let rootPair: ArtifactPair | undefined;
if (rootIndex >= 0) {
rootPair = pairs.splice(rootIndex, 1)[0];
}
let usedTokens = 0;
const parts: string[] = [];
// Maintenance reminder (lightweight)
const reminder =
"📋 Project map active: Start with the root `.pi-map.index.md`, use indexes first for routing, read the local `.pi-map.md` plus source before edits, run `project_map_patch` after source edits, and run `project_map_validate` before freshness-sensitive architectural handoff.";
parts.push(reminder);
usedTokens += estimateTokens(reminder);
// Root pair (guaranteed)
if (rootPair) {
const indexContent = readFileSync(join(cwd, rootPair.indexPath), "utf8");
const mapContent = readFileSync(join(cwd, rootPair.mapPath), "utf8");
const block = buildRootPairBlock(indexContent, mapContent);
parts.push(block);
usedTokens += estimateTokens(block);
}
// Budgeted expansion (shallow-first, deterministic)
for (const pair of pairs) {
const indexContent = readFileSync(join(cwd, pair.indexPath), "utf8");
const mapContent = readFileSync(join(cwd, pair.mapPath), "utf8");
const pairTokens =
estimateTokens(indexContent) + estimateTokens(mapContent);
if (usedTokens + pairTokens > budget) {
break;
}
parts.push(
`\n## ${pair.dir}\n\n### Index\n${indexContent}\n\n### Map\n${mapContent}`,
);
usedTokens += pairTokens;
}
return { content: parts.join("\n\n"), display: false };
}
+27
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@@ -290,6 +290,33 @@ describe("pi-extension", () => {
expect(result.message.display).toBe(false);
});
it("injects canonical root-pair block with real file content when maps exist and mode is strong", async () => {
const dir = mkdtempSync(join(tmpdir(), "pi-ext-test-"));
writeFileSync(join(dir, ".pi-map.md"), "# .\n## role\nRootMap\n");
writeFileSync(
join(dir, ".pi-map.index.md"),
"# . (index)\n## role\nRootIndex\n",
);
writeFileSync(
join(dir, ".pi-project-map.json"),
JSON.stringify({ promptInjectionMode: "strong" }),
);
mockCtx.cwd = dir;
const handler = registeredEvents.before_agent_start;
const result = await handler(null, mockCtx);
expect(result).toHaveProperty("message");
expect(result.message.display).toBe(false);
expect(result.message.content).toContain(
"<!-- PI_MAP_ROOT_PAIR_START -->",
);
expect(result.message.content).toContain("<!-- PI_MAP_ROOT_PAIR_END -->");
expect(result.message.content).toContain("RootMap");
expect(result.message.content).toContain("RootIndex");
expect(result.message.content).toContain("Trust boundary:");
});
it("returns empty object when no maps exist and mode is off", async () => {
const dir = mkdtempSync(join(tmpdir(), "pi-ext-test-"));
writeFileSync(
+136
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@@ -1,4 +1,7 @@
import { describe, it, expect } from "vitest";
import { mkdtempSync, writeFileSync, mkdirSync } from "fs";
import { join } from "path";
import { tmpdir } from "os";
import {
buildRootPairBlock,
hasRootPairMarker,
@@ -7,6 +10,10 @@ import {
modeAllowsPreInitHint,
modeAllowsInjection,
modeRequiresProtocolPath,
discoverContextWindow,
estimateTokens,
findAllArtifactPairs,
buildInjectionPayload,
ROOT_PAIR_START_MARKER,
ROOT_PAIR_END_MARKER,
TRUST_BOUNDARY_TEXT,
@@ -97,4 +104,133 @@ describe("prompt-injection helpers", () => {
expect(modeRequiresProtocolPath("strict")).toBe(true);
});
});
describe("context-window discovery", () => {
it("reads contextWindow from model metadata", () => {
const ctx = { model: { contextWindow: 256_000 } };
expect(discoverContextWindow(ctx)).toBe(256_000);
});
it("reads maxContextTokens from model metadata", () => {
const ctx = { model: { maxContextTokens: 128_000 } };
expect(discoverContextWindow(ctx)).toBe(128_000);
});
it("falls back to known model lookup by id", () => {
expect(discoverContextWindow({ model: { id: "gpt-4o-mini" } })).toBe(
128_000,
);
expect(discoverContextWindow({ model: { id: "kimi-for-coding" } })).toBe(
200_000,
);
});
it("returns undefined for unknown models", () => {
expect(
discoverContextWindow({ model: { id: "unknown-model" } }),
).toBeUndefined();
});
it("returns undefined when model is missing", () => {
expect(discoverContextWindow({})).toBeUndefined();
});
});
describe("token estimation", () => {
it("estimates tokens from character count", () => {
expect(estimateTokens("")).toBe(0);
expect(estimateTokens("abcd")).toBe(1);
expect(estimateTokens("abcde")).toBe(2);
});
});
describe("artifact-pair discovery", () => {
it("finds paired artifacts shallow-first", () => {
const dir = mkdtempSync(join(tmpdir(), "pi-pair-test-"));
mkdirSync(join(dir, "src", "nested"), { recursive: true });
writeFileSync(join(dir, ".pi-map.md"), "# root");
writeFileSync(join(dir, ".pi-map.index.md"), "# root index");
writeFileSync(join(dir, "src", ".pi-map.md"), "# src");
writeFileSync(join(dir, "src", ".pi-map.index.md"), "# src index");
writeFileSync(join(dir, "src", "nested", ".pi-map.md"), "# nested");
writeFileSync(
join(dir, "src", "nested", ".pi-map.index.md"),
"# nested index",
);
const pairs = findAllArtifactPairs(dir);
expect(pairs.map((p) => p.dir)).toEqual([".", "src", "src/nested"]);
});
it("ignores directories missing one of the paired artifacts", () => {
const dir = mkdtempSync(join(tmpdir(), "pi-pair-test-"));
writeFileSync(join(dir, ".pi-map.md"), "# root");
// missing .pi-map.index.md intentionally
expect(findAllArtifactPairs(dir)).toHaveLength(0);
});
});
describe("injection payload", () => {
it("always includes the root pair", () => {
const dir = mkdtempSync(join(tmpdir(), "pi-payload-test-"));
writeFileSync(join(dir, ".pi-map.md"), "# root map");
writeFileSync(join(dir, ".pi-map.index.md"), "# root index");
const payload = buildInjectionPayload(
dir,
{ contextBudgetPercent: 15, contextBudgetMaxTokens: 100_000 },
undefined,
);
expect(payload.content).toContain(ROOT_PAIR_START_MARKER);
expect(payload.content).toContain(ROOT_PAIR_END_MARKER);
expect(payload.content).toContain("# root map");
expect(payload.content).toContain("# root index");
expect(payload.display).toBe(false);
});
it("expands additional pairs when budget allows", () => {
const dir = mkdtempSync(join(tmpdir(), "pi-payload-test-"));
mkdirSync(join(dir, "src"), { recursive: true });
writeFileSync(join(dir, ".pi-map.md"), "# root map");
writeFileSync(join(dir, ".pi-map.index.md"), "# root index");
writeFileSync(join(dir, "src", ".pi-map.md"), "# src map");
writeFileSync(join(dir, "src", ".pi-map.index.md"), "# src index");
const payload = buildInjectionPayload(
dir,
{ contextBudgetPercent: 100, contextBudgetMaxTokens: 10_000 },
10_000,
);
expect(payload.content).toContain("# src map");
expect(payload.content).toContain("# src index");
});
it("stops expanding when budget is exhausted", () => {
const dir = mkdtempSync(join(tmpdir(), "pi-payload-test-"));
mkdirSync(join(dir, "src"), { recursive: true });
writeFileSync(join(dir, ".pi-map.md"), "# root map");
writeFileSync(join(dir, ".pi-map.index.md"), "# root index");
writeFileSync(
join(dir, "src", ".pi-map.md"),
`# src map ${"x".repeat(400)}`,
);
writeFileSync(
join(dir, "src", ".pi-map.index.md"),
`# src index ${"x".repeat(400)}`,
);
const payload = buildInjectionPayload(
dir,
{ contextBudgetPercent: 100, contextBudgetMaxTokens: 10 },
10_000,
);
expect(payload.content).toContain("# root map");
expect(payload.content).not.toContain("# src map x");
});
});
});