v1.13.17-cross-repo-reads: on-demand read access to paths outside the project root

When the agent needed context from another repo, pathGuard rejected every read
with no recovery path. This batch adds a reactive request_read_access flow:
pathGuard's error now hints at the tool, the model emits a structured request,
the inference loop pauses (same mechanism as ask_user_input), the user picks
Allow/Deny via inline chips, and subsequent reads under the granted root succeed
for the rest of the session.

Schema: sessions.allowed_read_paths TEXT[] NOT NULL DEFAULT ARRAY[]::TEXT[]
(idempotent ADD COLUMN IF NOT EXISTS).

Grant unit (design D1): nearest registered projects.path ancestor →
nearest repo-shaped ancestor (.git/ / package.json / go.mod / Cargo.toml)
under PROJECT_ROOT_WHITELIST → else refuse. grant_resolver.ts walks
ancestors with a per-iteration whitelist invariant check so symlinked
input can't escape the whitelist mid-walk (Sam's checkpoint-1 ask).

Path-guard: optional extraRoots arg threaded from session.allowed_read_paths
through executeToolCall to view_file / list_dir / grep / find_files. The
ToolDef.execute signature gets an optional third param; non-FS tools
ignore it. view_file re-anchors the secret-guard check on basename(real)
whenever a relative path starts with "../" so .env / id_rsa* etc. still
deny across grant roots.

Endpoint: POST /api/chats/:id/grant_read_access mirrors /answer_user_input.
On 'allow' it re-resolves the grant root (state may have changed since
prompt — auto-falls to denial reason text on failure, not 500), array_appends
to sessions.allowed_read_paths with in-memory dedup, then publishes
tool_result + session_updated frames and enqueues the next assistant turn.

PATCH /api/sessions/:id allowed_read_paths supports revocation only. Zod
refines absolute + no traversal markers; runtime findUnauthorizedAdditions
guard rejects any entry not already present in the row, so a malicious
curl -X PATCH -d '{"allowed_read_paths":["/etc"]}' returns 400 instead of
bypassing the grant flow (Sam's compliance-review action item).

Frontend: RequestReadAccessCard renders pending (path + reason + Allow/Deny)
and answered (granted/denied summary with the resolved root) variants;
MessageList.flatten/group special-cases the tool name; SettingsPane adds a
per-session grants list with per-row revoke that PATCHes the shortened
array.

Tests: 11 grant_resolver, 8 path_guard, 8 sessions PATCH subset, including
explicit cases for symlink escape mid-walk, walk-bound termination at
whitelist root, /etc bypass attempt via PATCH, and nearest-project
disambiguation. 292 total server tests green.

Pairs with v1.13.16-xml-parser — the model now self-recovers from both
a wrong tool name AND from a refused path.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/server/src/services/__tests__/grant_resolver.test.ts

@@ -0,0 +1,199 @@
+// v1.13.17-cross-repo-reads: resolveGrantRoot decision tree.
+//
+// Sam's dispatch note (2026-05-22): "in the project-root resolver ancestor
+// walk, stop the moment parent exits PROJECT_ROOT_WHITELIST or hits
+// filesystem root — check on every iteration, not just final parent.
+// Symlinked input must not be able to escape the whitelist during the
+// walk." The symlink-escape-mid-walk test below pins that invariant —
+// without the per-iteration whitelist check, this case would walk OUTSIDE
+// the whitelist root and return a phantom grant.
+
+import { describe, it, expect, beforeAll, afterAll, vi } from 'vitest';
+import { mkdtemp, rm, mkdir, writeFile, symlink } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { realpath } from 'node:fs/promises';
+import { resolveGrantRoot } from '../grant_resolver.js';
+import type { Sql } from '../../db.js';
+
+let tmp: string;
+let whitelist: string;
+let project: string;
+let fork: string;
+let outside: string;
+
+// Fake sql tag — returns the projects rows we want without touching a real
+// database. The resolver only ever does a single SELECT, so a single-shot
+// mock that returns the prepared rows on every invocation is enough.
+function makeSql(rows: Array<{ path: string }>): Sql {
+  const tag = ((..._args: unknown[]) => Promise.resolve(rows)) as unknown as Sql;
+  return tag;
+}
+
+beforeAll(async () => {
+  tmp = await realpath(await mkdtemp(join(tmpdir(), 'boocode-gr-')));
+  whitelist = join(tmp, 'whitelist');
+  project = join(whitelist, 'boocode');
+  fork = join(whitelist, 'forks', 'codecontext');
+  outside = join(tmp, 'outside');
+  await mkdir(project, { recursive: true });
+  await mkdir(fork, { recursive: true });
+  await mkdir(outside, { recursive: true });
+  // Mark project as a repo (.git directory).
+  await mkdir(join(project, '.git'));
+  await writeFile(join(project, 'README.md'), 'project readme');
+  // Mark fork as a repo via go.mod (matches the proposal's example).
+  await writeFile(join(fork, 'go.mod'), 'module example.com/foo');
+  await writeFile(join(fork, 'main.go'), 'package main');
+  await writeFile(join(outside, 'secret.txt'), 'forbidden');
+});
+
+afterAll(async () => {
+  await rm(tmp, { recursive: true, force: true });
+});
+
+describe('resolveGrantRoot — happy paths', () => {
+  it('refuses when the requested path is already under projectRoot', async () => {
+    const result = await resolveGrantRoot(makeSql([]), join(project, 'README.md'), project, whitelist);
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toMatch(/already accessible/);
+  });
+
+  it('returns the project root when the path falls under a registered project', async () => {
+    // Register `fork` as a known project. Resolver should return the project
+    // ancestor (LONGEST match wins) rather than the repo-shape fallback.
+    const result = await resolveGrantRoot(
+      makeSql([{ path: fork }]),
+      join(fork, 'main.go'),
+      project,
+      whitelist,
+    );
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.root).toBe(fork);
+      expect(result.source).toBe('project');
+    }
+  });
+
+  it('falls back to the nearest repo-shaped ancestor when no project matches', async () => {
+    const result = await resolveGrantRoot(
+      makeSql([]),
+      join(fork, 'main.go'),
+      project,
+      whitelist,
+    );
+    expect(result.ok).toBe(true);
+    if (result.ok) {
+      expect(result.root).toBe(fork);
+      expect(result.source).toBe('whitelist');
+    }
+  });
+});
+
+describe('resolveGrantRoot — refusals', () => {
+  it('refuses paths outside PROJECT_ROOT_WHITELIST', async () => {
+    const result = await resolveGrantRoot(
+      makeSql([]),
+      join(outside, 'secret.txt'),
+      project,
+      whitelist,
+    );
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toMatch(/outside permitted scope/);
+  });
+
+  it('refuses non-absolute paths', async () => {
+    const result = await resolveGrantRoot(makeSql([]), 'relative/path', project, whitelist);
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toMatch(/absolute/);
+  });
+
+  it('refuses missing paths without prompting', async () => {
+    const result = await resolveGrantRoot(
+      makeSql([]),
+      join(whitelist, 'nope'),
+      project,
+      whitelist,
+    );
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toMatch(/does not exist/);
+  });
+
+  it('refuses when no repo-shape marker is found before hitting the whitelist root', async () => {
+    // Build a directory tree under the whitelist that has NO repo markers
+    // all the way up to the whitelist root.
+    const plain = join(whitelist, 'plain-dir', 'nested');
+    await mkdir(plain, { recursive: true });
+    await writeFile(join(plain, 'just-a-file.txt'), 'x');
+    const result = await resolveGrantRoot(
+      makeSql([]),
+      join(plain, 'just-a-file.txt'),
+      project,
+      whitelist,
+    );
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toMatch(/no repo-shaped ancestor/);
+  });
+
+  it('does not grant the whitelist root itself as a fallback', async () => {
+    // Even if .git existed at the whitelist root (it doesn't), we'd refuse.
+    // Easier to assert: a path directly under whitelist with no repo marker.
+    const direct = join(whitelist, 'lone-file.txt');
+    await writeFile(direct, 'x');
+    const result = await resolveGrantRoot(makeSql([]), direct, project, whitelist);
+    expect(result.ok).toBe(false);
+  });
+});
+
+describe('resolveGrantRoot — symlink-escape-mid-walk guard (Sam 2026-05-22)', () => {
+  it('refuses a symlinked input whose realpath sits outside the whitelist', async () => {
+    // The symlink lives nominally inside the whitelist, but its target
+    // (realpath) is outside. The guard's first realpath() call normalizes
+    // and the up-front whitelist check refuses immediately.
+    const link = join(whitelist, 'escape-link');
+    try {
+      await symlink(outside, link);
+      const result = await resolveGrantRoot(
+        makeSql([]),
+        join(link, 'secret.txt'),
+        project,
+        whitelist,
+      );
+      expect(result.ok).toBe(false);
+      if (!result.ok) expect(result.reason).toMatch(/outside permitted scope/);
+    } finally {
+      await rm(link, { force: true });
+    }
+  });
+
+  it('walk loop terminates at the whitelist root, not at filesystem /', async () => {
+    // Construct a deep tree with NO repo markers anywhere. Without a bound,
+    // the walk would chase parents up to "/". The bound flips the loop into
+    // a refusal once the cursor equals the realpath'd whitelist root.
+    const deep = join(whitelist, 'a', 'b', 'c', 'd');
+    await mkdir(deep, { recursive: true });
+    await writeFile(join(deep, 'leaf.txt'), 'x');
+    const result = await resolveGrantRoot(makeSql([]), join(deep, 'leaf.txt'), project, whitelist);
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.reason).toMatch(/no repo-shaped ancestor/);
+  });
+});
+
+describe('resolveGrantRoot — nearest-project disambiguation', () => {
+  it('prefers the longest matching project path over a shorter ancestor', async () => {
+    const outer = whitelist;
+    const inner = fork; // /whitelist/forks/codecontext, deeper than outer
+    const result = await resolveGrantRoot(
+      makeSql([{ path: outer }, { path: inner }]),
+      join(fork, 'main.go'),
+      project,
+      whitelist,
+    );
+    expect(result.ok).toBe(true);
+    if (result.ok) expect(result.root).toBe(inner);
+  });
+});
+
+// Belt-and-suspenders: silence a known dynamic-import warning that vitest
+// occasionally emits on transient fs operations in CI but never in dev.
+vi.spyOn(console, 'warn').mockImplementation(() => {});

apps/server/src/services/__tests__/path_guard.test.ts

@@ -0,0 +1,93 @@
+// v1.13.17-cross-repo-reads: pathGuard now accepts an optional extraRoots
+// list. Validates the primary-root path stays the source of truth and that
+// extra roots are consulted when (and only when) the primary rejects.
+
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
+import { mkdtemp, rm, mkdir, writeFile, symlink } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+import { realpath } from 'node:fs/promises';
+import { pathGuard, PathScopeError } from '../path_guard.js';
+
+let tmp: string;
+let projectRoot: string;
+let altRoot: string;
+let outsideDir: string;
+
+beforeAll(async () => {
+  tmp = await realpath(await mkdtemp(join(tmpdir(), 'boocode-pg-')));
+  projectRoot = join(tmp, 'project');
+  altRoot = join(tmp, 'alt');
+  outsideDir = join(tmp, 'outside');
+  await mkdir(projectRoot, { recursive: true });
+  await mkdir(altRoot, { recursive: true });
+  await mkdir(outsideDir, { recursive: true });
+  await writeFile(join(projectRoot, 'inside.txt'), 'p');
+  await writeFile(join(altRoot, 'cross.txt'), 'a');
+  await writeFile(join(outsideDir, 'forbidden.txt'), 'x');
+});
+
+afterAll(async () => {
+  await rm(tmp, { recursive: true, force: true });
+});
+
+describe('pathGuard (v1.13.17 extraRoots)', () => {
+  it('accepts paths inside the primary projectRoot', async () => {
+    const real = await pathGuard(projectRoot, 'inside.txt');
+    expect(real).toBe(join(projectRoot, 'inside.txt'));
+  });
+
+  it('rejects paths outside the primary root when no extra roots given', async () => {
+    await expect(pathGuard(projectRoot, join(outsideDir, 'forbidden.txt'))).rejects.toBeInstanceOf(
+      PathScopeError,
+    );
+  });
+
+  it('accepts cross-root paths when the matching extra root is provided', async () => {
+    const real = await pathGuard(projectRoot, join(altRoot, 'cross.txt'), [altRoot]);
+    expect(real).toBe(join(altRoot, 'cross.txt'));
+  });
+
+  it('rejects cross-root paths even with extra roots when no root matches', async () => {
+    await expect(
+      pathGuard(projectRoot, join(outsideDir, 'forbidden.txt'), [altRoot]),
+    ).rejects.toBeInstanceOf(PathScopeError);
+  });
+
+  it('ignores empty-string extra roots silently', async () => {
+    const real = await pathGuard(projectRoot, join(altRoot, 'cross.txt'), ['', altRoot]);
+    expect(real).toBe(join(altRoot, 'cross.txt'));
+  });
+
+  it('error message contains the request_read_access hint when scope rejects', async () => {
+    try {
+      await pathGuard(projectRoot, join(outsideDir, 'forbidden.txt'));
+      throw new Error('should have thrown');
+    } catch (err) {
+      expect(err).toBeInstanceOf(PathScopeError);
+      expect((err as Error).message).toContain('request_read_access');
+    }
+  });
+
+  it('still resolves symlinks before the scope check', async () => {
+    const linkPath = join(projectRoot, 'link-to-outside');
+    await symlink(join(outsideDir, 'forbidden.txt'), linkPath);
+    // Symlink target escapes both primary and the single extra root, so
+    // even though the surface path "looks" inside projectRoot, the real
+    // path resolves outside and the guard rejects.
+    await expect(pathGuard(projectRoot, linkPath, [altRoot])).rejects.toBeInstanceOf(
+      PathScopeError,
+    );
+    // But adding outsideDir as an extra root accepts (realpath inside it).
+    const real = await pathGuard(projectRoot, linkPath, [altRoot, outsideDir]);
+    expect(real).toBe(join(outsideDir, 'forbidden.txt'));
+  });
+
+  it('tries extra roots in order until one accepts', async () => {
+    const real = await pathGuard(projectRoot, join(altRoot, 'cross.txt'), [
+      outsideDir, // rejects
+      altRoot,    // accepts
+    ]);
+    expect(real).toBe(join(altRoot, 'cross.txt'));
+  });
+});

apps/server/src/services/file_ops.ts

@@ -47,8 +47,12 @@ export interface FindFilesResult {
   truncated: boolean;
 }
 
-export async function listDir(projectRoot: string, relPath: string): Promise<ListDirResult> {
-  const real = await pathGuard(projectRoot, relPath);
+export async function listDir(
+  projectRoot: string,
+  relPath: string,
+  opts?: { extra_roots?: readonly string[] },
+): Promise<ListDirResult> {
+  const real = await pathGuard(projectRoot, relPath, opts?.extra_roots);
   const s = await stat(real);
   if (!s.isDirectory()) {
     throw new PathScopeError(`not a directory: ${relPath}`);
@@ -82,8 +86,12 @@ export async function listDir(projectRoot: string, relPath: string): Promise<Lis
   };
 }
 
-export async function viewFile(projectRoot: string, relPath: string): Promise<ViewFileResult> {
-  const real = await pathGuard(projectRoot, relPath);
+export async function viewFile(
+  projectRoot: string,
+  relPath: string,
+  opts?: { extra_roots?: readonly string[] },
+): Promise<ViewFileResult> {
+  const real = await pathGuard(projectRoot, relPath, opts?.extra_roots);
   const s = await stat(real);
   if (!s.isFile()) {
     throw new PathScopeError(`not a file: ${relPath}`);
@@ -119,10 +127,10 @@ interface RipgrepMatch {
 export async function grep(
   projectRoot: string,
   pattern: string,
-  opts?: { path?: string; max_matches?: number; case_sensitive?: boolean; hidden?: boolean }
+  opts?: { path?: string; max_matches?: number; case_sensitive?: boolean; hidden?: boolean; extra_roots?: readonly string[] }
 ): Promise<GrepResult> {
   const targetPath = opts?.path ?? projectRoot;
-  const target = await pathGuard(projectRoot, targetPath);
+  const target = await pathGuard(projectRoot, targetPath, opts?.extra_roots);
   const limit = Math.min(
     Math.max(opts?.max_matches ?? DEFAULT_GREP_RESULTS, 1),
     MAX_GREP_RESULTS
@@ -192,14 +200,14 @@ export async function grep(
 export async function findFiles(
   projectRoot: string,
   pattern?: string,
-  opts?: { type?: 'file' | 'dir'; max_results?: number; path?: string }
+  opts?: { type?: 'file' | 'dir'; max_results?: number; path?: string; extra_roots?: readonly string[] }
 ): Promise<FindFilesResult> {
   const limit = Math.min(
     Math.max(opts?.max_results ?? DEFAULT_FIND_RESULTS, 1),
     MAX_FIND_RESULTS
   );
   const target = opts?.path != null
-    ? await pathGuard(projectRoot, opts.path)
+    ? await pathGuard(projectRoot, opts.path, opts?.extra_roots)
     : projectRoot;
   const args = ['--files'];
   if (pattern) args.push('--glob', pattern);

apps/server/src/services/grant_resolver.ts

@@ -0,0 +1,161 @@
+// v1.13.17-cross-repo-reads: derives the grant root for a path the user is
+// being asked to approve cross-repo read access to.
+//
+// Per design decision D1: grant unit = nearest registered project root,
+// then nearest path-whitelist ancestor that looks like a repo root, then
+// refuse. Granting the literal file path is too narrow (next file in the
+// same repo re-prompts). Granting an arbitrary parent dir over-scopes.
+//
+// The resolver runs in two contexts:
+//   1. request_read_access.execute  — pre-prompt validation (cheap; bails
+//      early if the path can't plausibly be granted so the user is never
+//      asked about /etc/passwd)
+//   2. POST /api/chats/:id/grant_read_access — at decision time, re-derives
+//      the root and persists it on sessions.allowed_read_paths
+//
+// Sam (2026-05-22 dispatch confirmation): "in the project-root resolver
+// ancestor walk, stop the moment parent exits PROJECT_ROOT_WHITELIST or hits
+// filesystem root — check on every iteration, not just final parent.
+// Symlinked input must not be able to escape the whitelist during the
+// walk." Hence the loop here checks both the walk bound AND the still-
+// inside-whitelist invariant every step.
+
+import { access, realpath } from 'node:fs/promises';
+import { constants } from 'node:fs';
+import { dirname, isAbsolute, sep } from 'node:path';
+import type { Sql } from '../db.js';
+
+// Files whose presence in a directory marks it as a repo root for grant
+// purposes. Kept narrow on purpose; broader heuristics (e.g. ".project",
+// "pyproject.toml") can be added with measured intent. Each entry is a
+// literal basename — no globs.
+const REPO_MARKERS: ReadonlyArray<string> = [
+  '.git',
+  'package.json',
+  'go.mod',
+  'Cargo.toml',
+];
+
+export type GrantResolution =
+  | { ok: true; root: string; source: 'project' | 'whitelist' }
+  | { ok: false; reason: string };
+
+function isUnder(child: string, parent: string): boolean {
+  return child === parent || child.startsWith(parent + sep);
+}
+
+async function exists(path: string): Promise<boolean> {
+  try {
+    await access(path, constants.F_OK);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+async function isRepoShaped(dir: string): Promise<boolean> {
+  for (const marker of REPO_MARKERS) {
+    if (await exists(`${dir}${sep}${marker}`)) return true;
+  }
+  return false;
+}
+
+// Resolves an absolute path to its grant root or refuses with a reason
+// string suitable for surfacing to the model. Pure helper — no DB writes,
+// no broker publishes. Caller persists the root on session.allowed_read_paths
+// if it wants the grant to stick.
+//
+// Arguments:
+//   sql                   — used only to read projects.path (no writes)
+//   requestedPath         — absolute path the model wants to read
+//   projectRoot           — the session's primary project root (already
+//                           realpath'd by caller). Used to short-circuit
+//                           "already in scope".
+//   whitelistRoot         — PROJECT_ROOT_WHITELIST from config (default /opt).
+//                           Walk bound for the repo-shape fallback.
+//
+// Returns { ok: true, root, source } on success; { ok: false, reason } else.
+export async function resolveGrantRoot(
+  sql: Sql,
+  requestedPath: string,
+  projectRoot: string,
+  whitelistRoot: string,
+): Promise<GrantResolution> {
+  if (typeof requestedPath !== 'string' || requestedPath.length === 0) {
+    return { ok: false, reason: 'path is required' };
+  }
+  if (!isAbsolute(requestedPath)) {
+    return { ok: false, reason: 'path must be absolute' };
+  }
+
+  // Resolve symlinks so subsequent ancestor checks compare apples-to-apples
+  // with realpath'd projectRoot. If the path doesn't exist at all, bail
+  // before bothering the user — the model is asking about a phantom.
+  let real: string;
+  try {
+    real = await realpath(requestedPath);
+  } catch {
+    return { ok: false, reason: `path does not exist: ${requestedPath}` };
+  }
+
+  // Whitelist guard. Symlinked inputs can resolve outside the whitelist
+  // even when the surface-form path looks inside it; that's why we test
+  // the *real* path here, not the requested one.
+  let realWhitelist: string;
+  try {
+    realWhitelist = await realpath(whitelistRoot);
+  } catch {
+    return { ok: false, reason: `whitelist root does not exist: ${whitelistRoot}` };
+  }
+  if (!isUnder(real, realWhitelist)) {
+    return { ok: false, reason: 'path outside permitted scope' };
+  }
+
+  // Already in scope? No prompt needed; the tool's caller should retry.
+  if (isUnder(real, projectRoot)) {
+    return { ok: false, reason: 'path already accessible without a grant' };
+  }
+
+  // Look for a registered project whose root is an ancestor of the
+  // requested path. Pick the LONGEST match (nearest ancestor wins) so
+  // sub-projects don't get over-broadened.
+  const projectRows = await sql<{ path: string }[]>`
+    SELECT path FROM projects WHERE status = 'open'
+  `;
+  let bestProject: string | null = null;
+  for (const row of projectRows) {
+    if (!row.path) continue;
+    if (!isUnder(real, row.path)) continue;
+    if (bestProject === null || row.path.length > bestProject.length) {
+      bestProject = row.path;
+    }
+  }
+  if (bestProject !== null) {
+    return { ok: true, root: bestProject, source: 'project' };
+  }
+
+  // Repo-shape fallback. Walk from the requested path upward toward the
+  // whitelist root. At every iteration: confirm we're still inside the
+  // whitelist (so a symlinked component can't slip the bound mid-walk)
+  // and confirm we haven't hit the filesystem root. The first dir with a
+  // REPO_MARKER child is the grant root.
+  let cursor = real;
+  while (true) {
+    // Don't grant the whitelist root itself — that would be far too broad.
+    if (cursor === realWhitelist) {
+      return { ok: false, reason: 'no repo-shaped ancestor found under whitelist' };
+    }
+    if (!isUnder(cursor, realWhitelist)) {
+      return { ok: false, reason: 'path outside permitted scope' };
+    }
+    const parent = dirname(cursor);
+    if (parent === cursor) {
+      // Hit filesystem root without finding a repo marker.
+      return { ok: false, reason: 'no repo-shaped ancestor found under whitelist' };
+    }
+    if (await isRepoShaped(cursor)) {
+      return { ok: true, root: cursor, source: 'whitelist' };
+    }
+    cursor = parent;
+  }
+}

apps/server/src/services/inference/tool-phase.ts

@@ -10,6 +10,10 @@ import { insertParts, partsFromAssistantMessage, partsFromToolMessage } from './
 // dispatch layer we no longer know which format produced the call, and the
 // extra signal is harmless for Qwen-derived calls.
 import { formatUnknownToolError } from './tool-suggestions.js';
+// v1.13.17-cross-repo-reads: pre-prompt validation for request_read_access.
+// Resolves the grant root before pausing the loop so the user is never
+// prompted about paths we couldn't grant anyway (e.g. /etc/passwd).
+import { resolveGrantRoot } from '../grant_resolver.js';
 import type {
   InferenceContext,
   StreamResult,
@@ -28,7 +32,8 @@ import { SYNTHESIS_TOOLS, runSynthesisPass } from '../synthesisPipeline.js';
 
 async function executeToolCall(
   projectRoot: string,
-  toolCall: ToolCall
+  toolCall: ToolCall,
+  extraRoots: readonly string[],
 ): Promise<{ output: unknown; truncated: boolean; error?: string }> {
   const tool = TOOLS_BY_NAME[toolCall.name];
   if (!tool) {
@@ -63,7 +68,7 @@ async function executeToolCall(
     };
   }
   try {
-    const output = await tool.execute(parsed.data, projectRoot);
+    const output = await tool.execute(parsed.data, projectRoot, extraRoots);
     const truncated =
       typeof output === 'object' && output !== null && 'truncated' in output
         ? Boolean((output as { truncated: unknown }).truncated)
@@ -206,7 +211,71 @@ export async function executeToolPhase(
         );
         return;
       }
-      const tres = await executeToolCall(projectRoot, tc);
+      // v1.13.17-cross-repo-reads: request_read_access pauses identically to
+      // ask_user_input EXCEPT for an up-front validation pass — if the path
+      // can't be granted under the whitelist / repo-shape rules, surface an
+      // immediate denial without prompting the user. Per design D1, we never
+      // ask the user about /etc/passwd or paths outside PROJECT_ROOT_WHITELIST.
+      if (tc.name === 'request_read_access') {
+        const tcArgs = tc.args as { path?: unknown; reason?: unknown };
+        const requested =
+          typeof tcArgs.path === 'string' ? tcArgs.path : '';
+        const resolution = await resolveGrantRoot(
+          ctx.sql,
+          requested,
+          projectRoot,
+          ctx.config.PROJECT_ROOT_WHITELIST,
+        );
+        if (!resolution.ok) {
+          // Auto-deny without pausing. The model sees the reason on its
+          // next turn and decides what to do.
+          const stored = {
+            tool_call_id: tc.id,
+            output: `denied: ${resolution.reason}`,
+            truncated: false,
+          };
+          await ctx.sql`
+            UPDATE messages
+            SET tool_results = ${ctx.sql.json(stored as never)}
+            WHERE id = ${toolMessageId}
+          `;
+          await insertParts(
+            ctx.sql,
+            partsFromToolMessage({ tool_results: stored }).map((p) => ({
+              ...p,
+              message_id: toolMessageId,
+            })),
+          );
+          ctx.publish(sessionId, {
+            type: 'tool_result',
+            tool_message_id: toolMessageId,
+            chat_id: chatId,
+            tool_call_id: tc.id,
+            output: stored.output,
+            truncated: false,
+          });
+          return;
+        }
+        // Path is plausibly grantable — install the pending sentinel and
+        // pause. The grant endpoint re-derives the root at decision time
+        // (state may have changed in the meantime) so we don't stash it here.
+        pausingForUserInput = true;
+        const sentinel = { tool_call_id: tc.id, output: null, truncated: false };
+        await ctx.sql`
+          UPDATE messages
+          SET tool_results = ${ctx.sql.json(sentinel as never)}
+          WHERE id = ${toolMessageId}
+        `;
+        await insertParts(
+          ctx.sql,
+          partsFromToolMessage({ tool_results: sentinel }).map((p) => ({
+            ...p,
+            message_id: toolMessageId,
+          })),
+        );
+        return;
+      }
+      const tres = await executeToolCall(projectRoot, tc, session.allowed_read_paths);
       if (SYNTHESIS_TOOLS.has(tc.name)) {
         synthEntries.push({ tc, output: tres.output, ...(tres.error ? { error: tres.error } : {}) });
       }

apps/server/src/services/path_guard.ts

@@ -16,9 +16,22 @@ export async function resolveProjectRoot(projectPath: string): Promise<string> {
   }
 }
 
+function isUnder(real: string, root: string): boolean {
+  return real === root || real.startsWith(root + sep);
+}
+
+// v1.13.17-cross-repo-reads: pathGuard now accepts an optional extraRoots
+// list (typically session.allowed_read_paths). The primary projectRoot is
+// tried first; if the resolved path doesn't sit under it, each extraRoot is
+// tried in turn. Throws PathScopeError if no root accepts. The error message
+// includes a hint pointing the model at the request_read_access tool so it
+// can self-correct on the next turn — extraRoots IS the persistence
+// mechanism for those grants, so we only suggest it when there's a missing
+// grant to ask for (i.e. the path isn't already under any allowed root).
 export async function pathGuard(
   projectRoot: string,
-  requested: string
+  requested: string,
+  extraRoots: readonly string[] = [],
 ): Promise<string> {
   if (typeof requested !== 'string' || requested.length === 0) {
     throw new PathScopeError('path is required');
@@ -30,10 +43,13 @@ export async function pathGuard(
   } catch {
     throw new PathScopeError(`path does not exist: ${requested}`);
   }
-  if (real !== projectRoot && !real.startsWith(projectRoot + sep)) {
-    throw new PathScopeError(
-      `path escapes project root: ${requested} -> ${real}`
-    );
+  if (isUnder(real, projectRoot)) return real;
+  for (const extra of extraRoots) {
+    if (extra.length === 0) continue;
+    if (isUnder(real, extra)) return real;
   }
-  return real;
+  throw new PathScopeError(
+    `path escapes project root: ${requested} -> ${real}. ` +
+      `Use request_read_access(path, reason) to ask the user for permission.`,
+  );
 }

apps/server/src/services/request_read_access.ts

@@ -0,0 +1,82 @@
+// v1.13.17-cross-repo-reads: tool the model uses to request read access to
+// a path outside its session's primary project root. When the model emits
+// view_file("/opt/forks/foo/go.mod") under a session scoped to /opt/boocode,
+// pathGuard's error message hints at this tool. The model then emits
+//   request_read_access(path="/opt/forks/foo/go.mod",
+//                       reason="investigating foo to write the design doc")
+// The tool's execute does cheap up-front validation: if the requested path
+// can't possibly be granted under the current whitelist + repo-shape rules,
+// it returns a denial immediately without prompting the user. Otherwise, the
+// tool-phase pause branch (parallel of ask_user_input) stores a pending
+// sentinel and waits for the user's allow/deny via the grant_read_access
+// endpoint.
+//
+// The execute body never directly mutates state; the grant endpoint owns
+// the persistence path. This keeps the tool-side logic side-effect-free
+// (it's just a request) and matches ask_user_input's "server-side no-op
+// fallback, pause happens in tool-phase" shape.
+
+import { z } from 'zod';
+import type { ToolDef } from './tools.js';
+
+const RequestReadAccessInput = z.object({
+  path: z.string().min(1),
+  reason: z.string().min(1).max(500),
+});
+type RequestReadAccessInputT = z.infer<typeof RequestReadAccessInput>;
+
+export const requestReadAccess: ToolDef<RequestReadAccessInputT> = {
+  name: 'request_read_access',
+  description:
+    "Ask the user for read-only access to a path outside the current " +
+    "session's project scope. Use when a previous read tool (view_file, " +
+    'list_dir, grep, find_files) was refused with a path-escapes-project ' +
+    'error and the path is plausibly under another known repository (e.g. ' +
+    '/opt/forks/foo). Provide a short reason describing why you need the ' +
+    "access. Pauses the conversation until the user picks Allow or Deny; " +
+    'the next assistant turn sees the result. On Allow, the tool result ' +
+    'is "granted: <root>" — subsequent reads under that root succeed for ' +
+    'the rest of the session. On Deny, the tool result is "denied". Do ' +
+    'not call this for paths that are already inside the project root.',
+  inputSchema: RequestReadAccessInput,
+  jsonSchema: {
+    type: 'function',
+    function: {
+      name: 'request_read_access',
+      description:
+        "Ask the user for read-only access to a path outside the session's " +
+        'project scope. Pauses the conversation until the user picks Allow ' +
+        'or Deny. Subsequent reads under the granted root succeed for the ' +
+        'rest of the session.',
+      parameters: {
+        type: 'object',
+        properties: {
+          path: {
+            type: 'string',
+            description:
+              'Absolute path the model wants to read. Must be under the ' +
+              "server's PROJECT_ROOT_WHITELIST (default /opt) and outside " +
+              "the session's primary project root.",
+          },
+          reason: {
+            type: 'string',
+            description:
+              'Short rationale (<=500 chars) shown to the user explaining ' +
+              'why the access is needed. The user uses this to decide.',
+          },
+        },
+        required: ['path', 'reason'],
+        additionalProperties: false,
+      },
+    },
+  },
+  // Server-side no-op. The "execution" of request_read_access is the
+  // pause-and-resume cycle managed by tool-phase.ts + the grant endpoint.
+  // The inference loop catches this tool name BEFORE executeToolCall fires
+  // and inserts a pending sentinel instead — this fallback only runs if
+  // something bypasses that branch, in which case we surface the pending
+  // shape so downstream code can still detect it. Mirrors ask_user_input.
+  async execute(input) {
+    return { _pending: true, path: input.path, reason: input.reason };
+  },
+};

apps/server/src/services/tools.ts

@@ -22,6 +22,10 @@ import {
   getSemanticNeighborhoods,
   getFrameworkAnalysis,
 } from './tools/codecontext/index.js';
+// v1.13.17-cross-repo-reads: cross-repo read grant request tool. Paired
+// with the pause-on-pending-grant branch in inference/tool-phase.ts and the
+// POST /api/chats/:id/grant_read_access endpoint in routes/messages.ts.
+import { requestReadAccess } from './request_read_access.js';
 
 const MAX_FILE_BYTES = 5 * 1024 * 1024;
 const DEFAULT_VIEW_LINES = 200;
@@ -45,7 +49,13 @@ export interface ToolDef<TInput> {
   description: string;
   inputSchema: z.ZodType<TInput>;
   jsonSchema: ToolJsonSchema;
-  execute(input: TInput, projectRoot: string): Promise<unknown>;
+  // v1.13.17-cross-repo-reads: extraRoots is the session's
+  // allowed_read_paths, threaded through executeToolCall in tool-phase.ts.
+  // Only the filesystem tools (view_file, list_dir, grep, find_files,
+  // view_truncated_output) forward it to pathGuard; other tools accept the
+  // arg and ignore it. The execute signature stays compatible with
+  // pre-v1.13.17 callsites because the parameter is optional.
+  execute(input: TInput, projectRoot: string, extraRoots?: readonly string[]): Promise<unknown>;
 }
 
 const ViewFileInput = z.object({
@@ -78,14 +88,19 @@ export const viewFile: ToolDef<ViewFileInputT> = {
       },
     },
   },
-  async execute(input, projectRoot) {
-    const real = await pathGuard(projectRoot, input.path);
+  async execute(input, projectRoot, extraRoots) {
+    const real = await pathGuard(projectRoot, input.path, extraRoots);
     // v1.11.7: secret-file deny check. Test the project-relative path
     // (matches the form continue.dev's patterns expect: basenames + dir
     // segments). Throw a typed error so executeToolCall in inference.ts
     // surfaces a clear "blocked" message to the LLM instead of silently
     // returning content the user wanted hidden.
-    const relPath = relative(projectRoot, real) || basename(real);
+    // v1.13.17: when the resolved path is outside the primary projectRoot
+    // (i.e. via an allowed_read_paths grant), `relative()` returns "../…"
+    // which won't match secret-file basename patterns. Re-anchor on the
+    // file's basename so the secret deny still fires across all grant roots.
+    const rel = relative(projectRoot, real);
+    const relPath = rel && !rel.startsWith('..') ? rel : basename(real);
     if (isSecretPath(relPath)) {
       throw new SecretBlockedError(relPath);
     }
@@ -157,8 +172,8 @@ export const listDir: ToolDef<ListDirInputT> = {
       },
     },
   },
-  async execute(input, projectRoot) {
-    const real = await pathGuard(projectRoot, input.path);
+  async execute(input, projectRoot, extraRoots) {
+    const real = await pathGuard(projectRoot, input.path, extraRoots);
     const s = await stat(real);
     if (!s.isDirectory()) {
       throw new PathScopeError(`not a directory: ${input.path}`);
@@ -264,7 +279,7 @@ export const grep: ToolDef<GrepInputT> = {
       },
     },
   },
-  async execute(input, projectRoot) {
+  async execute(input, projectRoot, extraRoots) {
     const limit = Math.min(
       Math.max(input.max_results ?? DEFAULT_GREP_RESULTS, 1),
       MAX_GREP_RESULTS
@@ -276,6 +291,7 @@ export const grep: ToolDef<GrepInputT> = {
       max_matches: limit,
       case_sensitive: input.case_sensitive,
       hidden: input.hidden,
+      extra_roots: extraRoots,
     });
     const reshaped = result.matches.map((m) => ({
       path: m.path,
@@ -325,7 +341,7 @@ export const findFiles: ToolDef<FindFilesInputT> = {
       },
     },
   },
-  async execute(input, projectRoot) {
+  async execute(input, projectRoot, extraRoots) {
     const limit = Math.min(
       Math.max(input.max_results ?? DEFAULT_FIND_RESULTS, 1),
       MAX_FIND_RESULTS
@@ -335,6 +351,7 @@ export const findFiles: ToolDef<FindFilesInputT> = {
     const result = await fileOpsFindFiles(projectRoot, input.pattern, {
       path: input.path,
       max_results: limit,
+      extra_roots: extraRoots,
     });
     // v1.11.7: drop paths matching secret patterns. The original `total`
     // from file_ops includes pre-truncation count; we report the visible
@@ -383,7 +400,10 @@ export const viewTruncatedOutput: ToolDef<ViewTruncatedOutputInputT> = {
       },
     },
   },
-  async execute(input, _projectRoot) {
+  // view_truncated_output doesn't touch the filesystem — it pulls from tmpfs
+  // by opaque id. extraRoots is irrelevant here; declared for signature parity
+  // with the v1.13.17 ToolDef contract.
+  async execute(input, _projectRoot, _extraRoots) {
     const content = await readTruncation(input.id);
     if (content === null) {
       return {
@@ -658,6 +678,11 @@ export const ALL_TOOLS: ReadonlyArray<ToolDef<unknown>> = [
   watchChanges as ToolDef<unknown>,
   getSemanticNeighborhoods as ToolDef<unknown>,
   getFrameworkAnalysis as ToolDef<unknown>,
+  // v1.13.17-cross-repo-reads: paired with the pause-on-pending-grant
+  // branch in tool-phase.ts. Read-only — only ever READS files; the only
+  // state change is appending to sessions.allowed_read_paths via the
+  // grant endpoint, gated by user consent.
+  requestReadAccess as ToolDef<unknown>,
 ].sort((a, b) => a.name.localeCompare(b.name));
 
 // v1.8.2: forward-compatible read-only whitelist. An agent whose `tools` is
@@ -694,6 +719,10 @@ export const READ_ONLY_TOOL_NAMES = [
   'watch_changes',
   'get_semantic_neighborhoods',
   'get_framework_analysis',
+  // v1.13.17-cross-repo-reads: pauses execution but doesn't mutate project
+  // state directly (the grant endpoint appends to sessions.allowed_read_paths
+  // only with user consent). Belongs in the read-only budget tier.
+  'request_read_access',
 ] as const;
 
 export const TOOLS_BY_NAME: Record<string, ToolDef<unknown>> = Object.fromEntries(