fix: allow session-provenance canvas reads outside cwd (#134)

packages/extension/src/canvas-tool.ts

@@ -31,8 +31,8 @@ export function registerCanvasTool(pi: ExtensionAPI): void {
     promptSnippet:
       "Point the dashboard canvas at a deliverable you're producing (file, url, or a running dev server)",
     promptGuidelines: [
-      "Call canvas() when you produce or update a user-facing deliverable — a report/doc/mockup/image (target.kind='file', path relative to the session cwd), a web page (target.kind='url'), or a dev server you started (target.kind='server', port).",
-      "Paths MUST be relative to the session cwd — never absolute and never containing '..'.",
+      "Call canvas() when you produce or update a user-facing deliverable — a report/doc/mockup/image (target.kind='file', path relative to the session cwd or absolute file path), a web page (target.kind='url'), or a dev server you started (target.kind='server', port).",
+      "Paths can be relative to the session cwd or absolute — never containing '..'.",
       "This is fire-and-forget: it returns immediately and never blocks. Keep working after calling it.",
       "Use mode='pin' to keep the canvas on this artifact across later writes; default 'replace' lets the newest artifact take the slot.",
     ],
@@ -48,13 +48,13 @@ export function registerCanvasTool(pi: ExtensionAPI): void {
               [Type.Literal("file"), Type.Literal("url"), Type.Literal("server")],
               {
                 description:
-                  "'file' = a file relative to the session cwd (needs path); 'url' = a web page (needs url); 'server' = a running dev server (needs port).",
+                  "'file' = a file relative to the session cwd or absolute (needs path); 'url' = a web page (needs url); 'server' = a running dev server (needs port).",
               },
             ),
             path: Type.Optional(
               Type.String({
                 description:
-                  "Required for kind='file'. Relative to the session cwd — no absolute paths, no '..'.",
+                  "Required for kind='file'. Relative to the session cwd or absolute — no '..'.",
               }),
             ),
             url: Type.Optional(

packages/server/src/__tests__/canvas-accumulator.test.ts

@@ -7,6 +7,9 @@
  * (last declare wins), S21 (settings read-fresh, no cache).
  */
 
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
 import {
   type CanvasTypes,
   DEFAULT_CANVAS_TYPES,
@@ -184,4 +187,51 @@ describe("canvas accumulator", () => {
     const settle = h.intents.filter((i) => i.phase === "settle");
     expect(settle[0].target).toEqual({ kind: "file", cwd: CWD, path: "report.md" });
   });
+  it("records session provenance paths on tool_execution_end for existing files only", () => {
+    const recorded: Array<{ sessionId: string; path: string }> = [];
+    const acc = createCanvasAccumulator({
+      readCanvasTypes: () => DEFAULT_CANVAS_TYPES,
+      broadcastIntent: () => {},
+      broadcastServerChip: () => {},
+      broadcastServerChipExpire: () => {},
+      recordProvenancePath: (sessionId, path) => recorded.push({ sessionId, path }),
+    });
+
+    const tmpFile = path.join(os.tmpdir(), `prov-test-${Date.now()}.txt`);
+    fs.writeFileSync(tmpFile, "test content");
+
+    try {
+      // tool_execution_start MUST NOT record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_start", data: { toolName: "write", args: { path: tmpFile } } }, live);
+      expect(recorded).toHaveLength(0);
+
+      // Failed tool_execution_end MUST NOT record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_end", data: { toolName: "write", args: { path: tmpFile }, isError: true } }, live);
+      expect(recorded).toHaveLength(0);
+
+      // canvas() declare tool_execution_end MUST NOT record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_end", data: { toolName: "canvas", args: { target: { kind: "file", path: "/etc/passwd" } } } }, live);
+      expect(recorded).toHaveLength(0);
+
+      // Non-existent file tool_execution_end MUST NOT record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_end", data: { toolName: "write", args: { path: "/non/existent/file.txt" } } }, live);
+      expect(recorded).toHaveLength(0);
+
+      // Directory path tool_execution_end MUST NOT record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_end", data: { toolName: "write", args: { path: os.tmpdir() } } }, live);
+      expect(recorded).toHaveLength(0);
+
+      // Traversal attempt MUST NOT record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_end", data: { toolName: "write", args: { path: "../etc/passwd" } } }, live);
+      expect(recorded).toHaveLength(0);
+
+      // Successful tool_execution_end for existing file DOES record provenance
+      acc.onEvent("s1", { eventType: "tool_execution_end", data: { toolName: "write", args: { path: tmpFile } } }, live);
+      expect(recorded).toEqual([
+        { sessionId: "s1", path: fs.realpathSync(tmpFile) },
+      ]);
+    } finally {
+      if (fs.existsSync(tmpFile)) fs.unlinkSync(tmpFile);
+    }
+  });
 });

packages/server/src/__tests__/directory-service-openspec-enabled.test.ts

@@ -101,6 +101,9 @@ function makeSessionMgr(sessions: DashboardSession[] = []): SessionManager {
     get: (id: string) => map.get(id),
     listActive: () => Array.from(map.values()).filter(s => s.status !== "ended"),
     listAll: () => Array.from(map.values()),
+    addProvenancePath: vi.fn(),
+    getProvenancePathsForSession: () => new Set(),
+    getProvenancePathsForCwd: () => new Set(),
   };
 }
 

packages/server/src/__tests__/directory-service.test.ts

@@ -107,6 +107,9 @@ function createMockSessionManager(sessions: DashboardSession[] = []): SessionMan
     get: (id) => map.get(id),
     listActive: () => Array.from(map.values()).filter((s) => s.status !== "ended"),
     listAll: () => Array.from(map.values()),
+    addProvenancePath: vi.fn(),
+    getProvenancePathsForSession: () => new Set(),
+    getProvenancePathsForCwd: () => new Set(),
   };
 }