From a18fc6cf8cf5dd97bb940da069e65f6fa64e886c Mon Sep 17 00:00:00 2001
From: Jason Woltje <jason@diversecanvas.com>
Date: Tue, 20 Oct 2026 14:59:45 -0500
Subject: [PATCH] tasks: row 199 request calls use useFor keyed from the
 session; the host's start probe keeps use; a D5 test pins the use( call sites
 (#1697)

---
 packages/bus/tests/credential-store.test.mjs | 29 +++++++++++++++++++-
 packages/tasks/src/adapter.mjs               |  8 ++++--
 packages/tasks/src/startup.mjs               |  4 +--
 packages/tasks/src/verbs.mjs                 | 17 ++++++------
 4 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/packages/bus/tests/credential-store.test.mjs b/packages/bus/tests/credential-store.test.mjs
index eaade5140..3712abd02 100644
--- a/packages/bus/tests/credential-store.test.mjs
+++ b/packages/bus/tests/credential-store.test.mjs
@@ -2,7 +2,7 @@
 // <configDir>/secrets/agents/<business>/<agent>/<service>. Fake tokens in a scratch root only.
 import test from 'node:test';
 import assert from 'node:assert/strict';
-import { chmodSync, existsSync, mkdirSync, mkdtempSync, readdirSync, rmSync, statSync, symlinkSync, writeFileSync } from 'node:fs';
+import { chmodSync, existsSync, mkdirSync, mkdtempSync, readdirSync, readFileSync, rmSync, statSync, symlinkSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import { join } from 'node:path';
 import { Credentials } from '../src/credentials.mjs';
@@ -153,3 +153,30 @@ test('T5: delete refuses an agent dir holding anything but tokens', (t) => {
   assert.throws(() => c.remove('acme/coder'), /credential-file/);
   assert.equal(existsSync(join(s.storeRoot, 'acme', 'coder', 'notes')), true);
 });
+
+// Design D5: the name-keyed use() is the host's own, for @sync and the tracker's start check of each
+// role's token. Every other credential use goes through useFor, keyed from the broker's session. A
+// new use( call site outside this list fails here.
+test('D5: every credentials use( call site is on the allowlist', () => {
+  const packages = new URL('../../', import.meta.url);
+  const allowed = new Map([
+    ['bus/src/credentials.mjs', 1], // useFor's own call
+    ['tasks/src/adapter.mjs', 1], // the host's use(instance) for @sync and probe
+  ]);
+  const found = new Map();
+  const walk = (dir, rel) => {
+    for (const name of readdirSync(dir)) {
+      if (name === 'node_modules' || name === 'tests') continue;
+      const path = join(dir, name);
+      if (statSync(path).isDirectory()) walk(path, `${rel}${name}/`);
+      else if (name.endsWith('.mjs') || name.endsWith('.js')) {
+        const code = readFileSync(path, 'utf8').split('\n').filter((line) => !/^\s*\/\//.test(line)).join('\n');
+        const n = (code.match(/(?:credentials|this)\.use\(/g) ?? []).length;
+        if (n) found.set(`${rel}${name}`, n);
+      }
+    }
+  };
+  for (const pkg of readdirSync(packages)) if (statSync(new URL(`${pkg}/src`, packages), { throwIfNoEntry: false })?.isDirectory())
+    walk(new URL(`${pkg}/src`, packages).pathname, `${pkg}/src/`);
+  assert.deepEqual(Object.fromEntries([...found].sort()), Object.fromEntries([...allowed].sort()));
+});
diff --git a/packages/tasks/src/adapter.mjs b/packages/tasks/src/adapter.mjs
index 6a1f77e97..a78062048 100644
--- a/packages/tasks/src/adapter.mjs
+++ b/packages/tasks/src/adapter.mjs
@@ -80,7 +80,11 @@ export function tasksAdapter({
         tree: null,
         bots: new Set([businesses[name].tracker.sync.botId, ...Object.values(s.roles).map((r) => r.botId)]),
         sync: use('@sync'),
-        as: (role, method, path, opts) => use(role)(method, path, opts),
+        // Row 199 (#1697, design D5): a request's call keys from the broker's session for its cap,
+        // never from a role name. probe is the host's own start check of each role's token.
+        as: (session, method, path, opts) =>
+          credentials.useFor(session, 'vikunja', (token) => call(token, method, path, opts)),
+        probe: (role, method, path, opts) => use(role)(method, path, opts),
         state: 'starting',
         refused: null,
         queue: Promise.resolve(),
@@ -96,7 +100,7 @@ export function tasksAdapter({
         timers: [],
       };
       ctx.syncCall = (_token, method, path, opts) => ctx.sync(method, path, opts);
-      ctx.asCall = (role) => (_token, method, path, opts) => ctx.as(role, method, path, opts);
+      ctx.asCall = (role) => (_token, method, path, opts) => ctx.probe(role, method, path, opts);
       ctx.handle = verbs(ctx);
       contexts.set(name, ctx);
     }
diff --git a/packages/tasks/src/startup.mjs b/packages/tasks/src/startup.mjs
index f3bdc3d5d..8eaeccb00 100644
--- a/packages/tasks/src/startup.mjs
+++ b/packages/tasks/src/startup.mjs
@@ -41,7 +41,7 @@ export async function startup(ctx) {
   if (probe.status === 404 || probe.status === 403 || outcome(probe) === 'ok') refuse('scope-too-broad');
   expect(probe, 401, 'tracker-unexpected');
   for (const [role, r] of Object.entries(ctx.roles)) {
-    const control = await ctx.as(role, 'GET', `/tasks/${MISSING}`);
+    const control = await ctx.probe(role, 'GET', `/tasks/${MISSING}`);
     if (control.status !== 404 || control.json?.code !== 4002) {
       expect(control, 404, 'tracker-unexpected');
       refuse('tracker-unexpected');
@@ -49,7 +49,7 @@ export async function startup(ctx) {
     const probes = [['DELETE', `/tasks/${MISSING}`, undefined]];
     if (r.definition !== 'pm') probes.push(['POST', `/tasks/${MISSING}/labels`, { label_id: 1 }]);
     for (const [method, path, body] of probes) {
-      const p = await ctx.as(role, method, path, { body });
+      const p = await ctx.probe(role, method, path, { body });
       if (p.status === 404 || p.status === 403 || outcome(p) === 'ok') refuse('scope-too-broad');
       if (p.status !== 401) refuse(p.status === 0 || p.status >= 500 ? 'tracker-unavailable' : 'tracker-unexpected');
     }
diff --git a/packages/tasks/src/verbs.mjs b/packages/tasks/src/verbs.mjs
index dfd6bb1d3..fc3191535 100644
--- a/packages/tasks/src/verbs.mjs
+++ b/packages/tasks/src/verbs.mjs
@@ -122,8 +122,9 @@ export function verbs(ctx) {
   const relatedTo = (task, kind, other) =>
     Array.isArray(task.related_tasks?.[kind]) && task.related_tasks[kind].some((t) => t?.id === other);
   // One write with the acting role's token. An uncertain answer is settled by a re-read.
-  async function step(role, method, path, body, at, done) {
-    const r = await ctx.as(role, method, path, { body });
+  // `me` is the broker's session for the caller's cap (design D5).
+  async function step(me, method, path, body, at, done) {
+    const r = await ctx.as(me, method, path, { body });
     const o = outcome(r);
     if (o === 'ok') return r;
     if (o === 'uncertain' && at !== null && done) {
@@ -144,7 +145,7 @@ export function verbs(ctx) {
     if (!mine) fail('tracker-role');
     if (PM_VERBS.has(verb) && mine.definition !== 'pm') fail('field-writer');
     const plan = prepare(verb, args, role, mine);
-    if (verb === 'task.create') return create(cap, role, plan);
+    if (verb === 'task.create') return create(cap, me, plan);
     const at = target(args.task_ref);
     const before = await read(at);
     if (args.expect !== undefined && args.expect !== before.digest) {
@@ -165,7 +166,7 @@ export function verbs(ctx) {
     let landed = 0;
     try {
       for (const [method, path, body, done] of work.steps) {
-        await step(role, method, path, body, at, done);
+        await step(me, method, path, body, at, done);
         landed++;
       }
     } catch (e) {
@@ -385,12 +386,12 @@ export function verbs(ctx) {
         fail('unknown-verb');
     }
   }
-  async function create(cap, role, plan) {
+  async function create(cap, me, plan) {
     if (!ctx.broker.taskView(ctx.business, 'input', plan.request)) fail('request-not-found');
     await located(plan.others);
     ctx.broker.authorize(cap, 'task.create', { decision: plan.decision, target: null });
     // No re-read can find a create whose answer was lost, so an uncertain create is reported as such.
-    const r = await step(role, 'POST', `/projects/${plan.at.project}/tasks`, plan.body, null, null);
+    const r = await step(me, 'POST', `/projects/${plan.at.project}/tasks`, plan.body, null, null);
     if (r.status !== 201 && r.status !== 200) fail('tracker-unexpected');
     checkTask(r.json);
     const id = r.json.id;
@@ -399,9 +400,9 @@ export function verbs(ctx) {
     let failure = null;
     try {
       for (const l of plan.labels)
-        await step(role, 'POST', `/tasks/${id}/labels`, { label_id: l }, at, (a) => a.fields.labels.includes(l));
+        await step(me, 'POST', `/tasks/${id}/labels`, { label_id: l }, at, (a) => a.fields.labels.includes(l));
       for (const x of plan.relations)
-        await step(role, 'POST', `/tasks/${id}/relations`, { other_task_id: x.other, relation_kind: x.kind }, at, (a) =>
+        await step(me, 'POST', `/tasks/${id}/relations`, { other_task_id: x.other, relation_kind: x.kind }, at, (a) =>
           relatedTo(a.task, x.kind, x.other),
         );
     } catch (e) {