deepseek-harness/apps/cli/tests/web-agent-presets.e2e.ts

import { randomUUID } from 'node:crypto'
import { mkdir, mkdtemp, readFile, stat, writeFile } from 'node:fs/promises'
import { tmpdir } from 'node:os'
import { fileURLToPath } from 'node:url'
import { dirname, join } from 'node:path'
import { Context } from '@deepseek-ai/cordis'
import { boot, healProfilesModuleFallback, loadOverlayPatches } from '@deepseek-ai/dsh-app-boot'
import { provideCmdline } from '@deepseek-ai/dsh-cmdline'
import { SessionId } from '@deepseek-ai/dsh-session'
import type { Agent } from '@deepseek-ai/dsh-agent'
import type { PatchOptions } from '@deepseek-ai/cordis-plugin-include'
import { afterAll, beforeAll, describe, expect, it } from 'vitest'
import { settingsNamespace } from '@deepseek-ai/dsh-settings'
import { resolveSessionPreset, SETTINGS_NAMESPACE } from '@deepseek-ai/dsh-agent-presets'
import { applyChildComposition, childSessionMeta } from '@deepseek-ai/dsh-subagent'
import { CallId } from '@deepseek-ai/dsh-llm'
import type { BasicCompactService } from '@deepseek-ai/dsh-compact-basic'
import type {} from '@deepseek-ai/dsh-skill'
import type {} from '@deepseek-ai/dsh-tools'
// Type-only: resolves `ctx.get('sessionProjections')` and `ctx.get('tokenMeter')`.
import type {} from '@deepseek-ai/dsh-session-projection'
import type {} from '@deepseek-ai/dsh-token-meter'

const CONFIG_DIR = fileURLToPath(new URL('../config/', import.meta.url))
const REPO_ROOT = fileURLToPath(new URL('../../..', import.meta.url))
/** The shipped Web surface: the dsh-base and dsh-web-app bundle patches over an empty preset root. */
const BASE_PATCH = join(REPO_ROOT, 'packages/bundle/base/cordis.patch.yml')
const WEB_PATCH = join(REPO_ROOT, 'packages/bundle/web-app/cordis.patch.yml')
/** The installation anchor whose dependency surface the preset module fallback mirrors. */
const INSTALL_ANCHOR = join(REPO_ROOT, 'apps/cli/package.json')
const MINIMAL_PROMPT = 'You are a helpful software engineer assistant.'
const MINIMAL_BASH_DESCRIPTION = `Run commands in a bash shell
* When invoking this tool, the contents of the "command" parameter does NOT need to be XML-escaped.
* You don't have access to the internet via this tool.
* You do have access to a mirror of common linux and python packages via apt and pip.
* State is persistent across command calls and discussions with the user.
* To inspect a particular line range of a file, e.g. lines 10-25, try 'sed -n 10,25p /path/to/the/file'.
* Please avoid commands that may produce a very large amount of output.
* Please run long lived commands in the background, e.g. 'sleep 10 &' or start a server in the background.`

/**
 * Boot the shipped Web composition, minus the rows that would bind a port,
 * touch the network, or write outside the test. Everything that decides an
 * agent's capabilities is the real thing, including both shipped presets.
 */
async function bootWeb(settingsFile: string, extra: PatchOptions[] = []): Promise<Context> {
  const storageRoot = join(dirname(settingsFile), 'storages')
  const patches: PatchOptions[] = [
    ...loadOverlayPatches('dsh-test', BASE_PATCH),
    ...loadOverlayPatches('dsh-test', WEB_PATCH),
    // The settings row defaults to `$DSH_HOME/settings.yaml`. Left alone it
    // reads the developer's own document — and since the default preset is a
    // setting, a stored `agent-presets.default` would decide this file's
    // outcome. Point it at a temp file for the same reason the roster below
    // names only the shipped root.
    { id: 'settings', config: { path: settingsFile, watch: false } },
    // storage-json's root is anchored to the real $DSH_HOME. Unpinned, this
    // file writes the developer's own `~/.dsh/storages/` — and then reads it
    // back on the next run, so a stored document from any other build decides
    // this test's boot. Same reason the settings row above is pinned.
    { id: 'storage-json', config: { root: storageRoot } },
    // Host rows with side effects outside this process: a bound port, a served
    // asset tree, a telemetry exporter. `api-gateway` and `directory-picker`
    // stay ENABLED on purpose — the api-proxy is the host row that injects
    // `subagents`, `workspace`, and the rest of the agent plane, so disabling
    // it would hide exactly the breakage this file exists to catch: a service
    // moved into the presets that a host row still waits for. The boot audit
    // is that assertion.
    { id: 'webserver', disabled: true },
    // The web bundle's runtime row injects `httpServer`, so it cannot
    // activate without the bound port disabled above. It owns dist serving
    // and the URL prompt line — surface glue, not anything that decides an
    // agent's capabilities, which is all this file asserts.
    { id: 'web-runtime', disabled: true },
    { id: 'telemetry-otel', disabled: true },
    // A deployment-level skill on the host registry's GLOBAL layer — the same
    // registration shape a repository plugin's skill root uses. The layered
    // skills test below proves it reaches preset-composed agents.
    { id: 'skill-badge', disabled: false },
    { id: 'modules', disabled: true },
    { id: 'connection', disabled: true },
    // The shipped `-auto` chooser resolves its interaction from a running
    // host and so waits for the webserver disabled above; the browse variant
    // supplies `directoryPicker` without one.
    { id: 'directory-picker', disabled: true },
    { insert: [{ id: 'directory-picker-browse', name: '@deepseek-ai/dsh-host-directory-picker-browse' }] },
    // The roster AppCLIEntry would patch in; only the shipped root, so a
    // developer's own `~/.dsh/.preset` cannot change this test's outcome.
    // `default` here is the COMPOSITION default — the base layer the settings
    // document overrides.
    {
      id: 'agent-presets',
      config: { default: 'standard', roots: [{ path: join(CONFIG_DIR, 'agent-presets'), trust: 'system' }] },
    },
    ...extra,
  ]
  // The surface is patch layers over an empty preset root, so the root sits
  // outside this workspace and bare plugin names cannot resolve by Node's
  // upward walk. The flat fallback the preset boot maintains is what makes
  // them resolvable — the same mechanism, not a test-only shim.
  const home = dirname(settingsFile)
  healProfilesModuleFallback(INSTALL_ANCHOR, home)
  const profileDir = join(home, 'profiles', 'spec')
  await mkdir(profileDir, { recursive: true })
  const rootConfig = join(profileDir, 'cordis.yml')
  await writeFile(rootConfig, '[]\n')
  return await boot('dsh-test', rootConfig, patches, (bootCtx) => {
    provideCmdline(bootCtx, { args: [], exit: () => {} })
  })
}

const toolNames = (ctx: Context, agent?: Agent): string[] =>
  ctx.tools.schemas(agent).map(schema => schema.name).sort()

function enablePresetTool(composition: string, id: string): string {
  const row = `    - id: ${id}\n`
  const start = composition.indexOf(row)
  if (start < 0) throw new Error(`missing preset row ${id}`)
  const end = composition.indexOf('\n    - id:', start + row.length)
  const disabled = composition.indexOf('      disabled: true\n', start)
  if (disabled < 0 || (end >= 0 && disabled > end)) {
    throw new Error(`preset row ${id} is not disabled`)
  }
  return composition.slice(0, disabled) + composition.slice(disabled + '      disabled: true\n'.length)
}

let ctx: Context
beforeAll(async () => {
  const settingsFile = join(await mkdtemp(join(tmpdir(), 'dsh-web-presets-')), 'settings.yaml')
  await writeFile(settingsFile, '{}\n')
  ctx = await bootWeb(settingsFile)
}, 120_000)

describe('the shipped Web composition', () => {
  it('leaves the global tool layer empty', () => {
    // Every model-facing tool belongs to a preset, `ask_user_question`
    // included: a tool in the global layer reaches EVERY agent regardless of
    // which preset composed it, so a two-tool benchmark surface would really
    // present three. A regression here means an agent-plane row came back to
    // the host composition.
    expect(toolNames(ctx)).toEqual([])
  })

  it('keeps the token meter and its context-meter projections on the host plane', async () => {
    // Read before any preset in this file mounts, which is what makes this an
    // ownership assertion rather than a mount-order coincidence: a preset-side
    // meter sits behind an `isolate` realm and is invisible to `ctx.get`.
    //
    // The projection registry is process-wide rather than scope-layered, so a
    // preset-side meter would also make the browser's context meter appear for
    // a `minimal` session the moment some OTHER session mounted a preset that
    // carries one, and vanish entirely in a process that only ever ran
    // `minimal`. Host ownership is what makes the meter a per-session fact.
    expect(ctx.get('tokenMeter')).toBeDefined()
    const projections = ctx.get('sessionProjections')
    if (projections === undefined) throw new Error('the Web composition must compose a projection registry')
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-minimal-meter'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'minimal').then(() => undefined),
    })
    try {
      // A subset assertion: `tasks`, `goal`, and the rest register into the
      // same process-wide table, and this is about the meter's three units.
      expect(Object.keys(projections.snapshot(handle.agent.session).values))
        .toEqual(expect.arrayContaining(['contextBreakdown', 'contextPressure', 'tokenUsage']))
    } finally {
      await handle.dispose()
    }
  })

  it('supplies both shipped presets, and only those, from the system root', async () => {
    const listed = await ctx.agentPresets.list()

    expect(listed.map(preset => preset.id).sort()).toEqual(['code', 'cordis', 'minimal', 'standard'])
    expect(listed.every(preset => preset.trust === 'system')).toBe(true)
    expect(ctx.agentPresets.defaultId).toBe('standard')
  })

  it('composes the full agent from `standard`', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-standard'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    try {
      // The EXACT catalog, not a spot-check: an omission is this design's
      // quietest failure mode, because a row that registers into the wrong
      // layer mounts cleanly and simply contributes nothing. `glob`/`grep` are
      // excluded for the reason the TUI composition e2e excludes them — they
      // depend on ripgrep being present on the machine.
      expect(toolNames(ctx, handle.agent).filter(name => name !== 'glob' && name !== 'grep')).toEqual([
        'ask_user_question', 'bash', 'create_goal', 'edit', 'exit_plan_mode',
        'get_goal', 'interrupt_agent', 'list_agents', 'ralph', 'read', 'read_image', 'send_message', 'skill',
        'subagent', 'subagent_fork', 'task_kill',
        'task_list', 'task_output', 'todo_write', 'update_goal', 'web_search',
        'workflow', 'write',
      ])
    } finally {
      await handle.dispose()
    }
  })

  it('composes the exact RL prompt and two tools from `minimal`', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-minimal'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'minimal').then(() => undefined),
    })
    try {
      const assembly = await ctx.systemPrompt.assemble({ scope: handle.agent })
      expect(assembly.sections).toEqual([
        { name: 'deployment:persona', text: MINIMAL_PROMPT },
      ])
      expect(assembly.tools.map(tool => tool.name)).toEqual(['bash', 'str_replace_editor'])
      expect(assembly.tools.find(tool => tool.name === 'bash')?.description).toBe(MINIMAL_BASH_DESCRIPTION)
      expect(JSON.stringify(assembly.tools.find(tool => tool.name === 'str_replace_editor')?.parameters))
        .toContain('Absolute path')
      const compact = ctx.agentPresets.serviceFor(handle.agent, 'compact')
      expect(compact).toBeDefined()
      expect((compact as BasicCompactService).config).toMatchObject({
        thresholdRatio: 0.8,
        retainTokens: 20480,
        summarizationProvider: '',
        summarizationModel: '',
        maxTokens: 8192,
        compactionRetries: 1,
      })
    } finally {
      await handle.dispose()
    }
  })

  it('keeps two differently composed sessions independent', async () => {
    const full = await ctx.agents.create({
      sessionId: SessionId('preset-both-full'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    const minimal = await ctx.agents.create({
      sessionId: SessionId('preset-both-minimal'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'minimal').then(() => undefined),
    })
    try {
      expect(toolNames(ctx, minimal.agent)).toEqual(['bash', 'str_replace_editor'])
      expect(toolNames(ctx, full.agent).length).toBeGreaterThan(10)

      await minimal.dispose()

      // Tearing the minimal session down leaves the full one whole.
      expect(toolNames(ctx, full.agent).length).toBeGreaterThan(10)
      expect(toolNames(ctx)).toEqual([])
    } finally {
      await full.dispose()
    }
  })

  it('composes the cordis agent with its own toolset', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-cordis'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'cordis').then(() => undefined),
    })
    try {
      const tools = toolNames(ctx, handle.agent)
      // The self-referential toolset is what distinguishes this preset.
      expect(tools).toEqual(expect.arrayContaining(['cordis_inspect', 'cordis_mount', 'cordis_unmount']))
      // And it keeps the standard agent's own tools rather than replacing them.
      expect(tools).toEqual(expect.arrayContaining(['bash', 'read', 'edit', 'skill']))
      expect(tools).not.toContain('str_replace_editor')

      // The preset's own authoring skill registers into ITS layer of the host
      // registry: the cordis agent's view carries it, the global view does not.
      const scoped = (await ctx.skills.list({ scope: handle.agent })).map(skill => skill.name)
      expect(scoped).toContain('editing-cordis-compositions')
      expect((await ctx.skills.list()).map(skill => skill.name)).not.toContain('editing-cordis-compositions')
    } finally {
      await handle.dispose()
    }
  })

  it('presents `code` as Code Mode without disturbing a native session beside it', async () => {
    const coded = await ctx.agents.create({
      sessionId: SessionId('preset-code'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'code').then(() => undefined),
    })
    const native = await ctx.agents.create({
      sessionId: SessionId('preset-code-native'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    try {
      // One tool reaches the MODEL: the transport. The registry's catalog for
      // this agent is unchanged — a code mode collapses the presentation, not
      // the capabilities — so the assembly is what carries the claim.
      const assembly = await ctx.systemPrompt.assemble({ scope: coded.agent })
      expect(assembly.tools.map(tool => tool.name)).toEqual(['run_code'])
      expect(toolNames(ctx, coded.agent)).not.toContain('str_replace_editor')
      const sdk = assembly.sections.find(section => section.name === 'tools:sdk')?.text ?? ''
      expect(sdk).not.toContain('str_replace_editor')
      expect(sdk).toContain('web_search')

      // The presentation is this agent's alone: the deployment default is
      // native, and the session composed from `standard` still sees it.
      const nativeAssembly = await ctx.systemPrompt.assemble({ scope: native.agent })
      expect(nativeAssembly.tools.map(tool => tool.name)).toContain('bash')
      expect(nativeAssembly.tools.map(tool => tool.name)).not.toContain('run_code')
      expect(nativeAssembly.sections.some(section => section.name === 'tools:sdk')).toBe(false)
    } finally {
      await native.dispose()
      await coded.dispose()
    }
  })

  it('keeps the self-referential toolset out of every other preset', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-no-cordis'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    try {
      // Editing the live runtime is opt-in per session, not ambient.
      expect(toolNames(ctx, handle.agent)).not.toContain('cordis_mount')
    } finally {
      await handle.dispose()
    }
  })

  it('ships the composition-authoring skill inside the preset directory', async () => {
    // The preset's skill root is derived from its own `baseUrl`, so the skill
    // travels with the directory wherever the preset is installed.
    const skill = join(
      CONFIG_DIR, 'agent-presets', 'cordis', 'skills', 'editing-cordis-compositions', 'SKILL.md',
    )

    expect((await readFile(skill, 'utf8')).startsWith('---\nname: editing-cordis-compositions')).toBe(true)
  })

  it('merges the global skill layer into a preset agent\'s catalog, keeping local discovery preset-side', async () => {
    const proj = await mkdtemp(join(tmpdir(), 'dsh-preset-skill-proj-'))
    await mkdir(join(proj, '.dsh', 'skills', 'project-proof'), { recursive: true })
    await writeFile(join(proj, '.dsh', 'skills', 'project-proof', 'SKILL.md'), [
      '---',
      'name: project-proof',
      'description: Proves the preset layer discovers project skills beside global ones.',
      '---',
      '',
      'Project proof body.',
      '',
    ].join('\n'))

    const handle = await ctx.agents.create({
      // Unique per run: the composition persists into the ambient DSH home,
      // and a fixed id would collide with a log an earlier run left there.
      sessionId: SessionId(`preset-skills-standard-${randomUUID()}`),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    try {
      // The host (global) view carries the deployment-level provider alone:
      // local discovery moved behind the presets with `skill-local`.
      expect((await ctx.skills.list({ cwd: proj })).map(skill => skill.name)).toEqual(['dsh-badge'])

      // The standard agent's view merges the global layer with its preset's
      // own local discovery over the session cwd.
      const scoped = (await ctx.skills.list({ cwd: proj, scope: handle.agent })).map(skill => skill.name)
      expect(scoped).toContain('dsh-badge')
      expect(scoped).toContain('project-proof')

      // The preset's own loader tool resolves the global-layer skill.
      const loaded = await ctx.tools.execute({
        callId: CallId('preset-skills-load'),
        name: 'skill',
        arguments: { name: 'dsh-badge' },
        signal: new AbortController().signal,
        agent: handle.agent,
      })
      expect(loaded.isError).toBe(false)
      expect(JSON.stringify(loaded.content)).toContain('powered by dsh')
    } finally {
      await handle.dispose()
    }
  })

  it('shows a minimal agent the global layer but no loader tool', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId(`preset-skills-minimal-${randomUUID()}`),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'minimal').then(() => undefined),
    })
    try {
      // Layer visibility is the registry's; whether an agent can USE skills
      // stays the preset's choice — minimal mounts no `tool-skill`, so its
      // tool table has no loader even though the global layer is readable.
      expect((await ctx.skills.list({ scope: handle.agent })).map(skill => skill.name)).toContain('dsh-badge')
      expect(toolNames(ctx, handle.agent)).toEqual(['bash', 'str_replace_editor'])
    } finally {
      await handle.dispose()
    }
  })

  it('never rewrites the preset file it composed from', async () => {
    // The Loader persists a tree whose plugin self-disposed, and tearing an
    // agent down disposes its whole subtree. Inherited, that rewrote the
    // shipped composition — truncating it to `[]` the first time a session
    // ended — so `PresetTree` refuses to write at all.
    const path = join(CONFIG_DIR, 'agent-presets', 'standard', 'agent.cordis.yml')
    const before = await readFile(path, 'utf8')

    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-readonly'),
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    await handle.dispose()
    // Slack, not a race the number has to win. The write is driven by the
    // Loader's fiber-unload listener, which fires as the subtree's fibers
    // settle rather than when `dispose()` resolves, and the Loader exposes no
    // flush to await. A regression writes synchronously inside that listener,
    // so any wait past settlement fails; a longer one only slows the test.
    await new Promise(resolve => setTimeout(resolve, 50))

    expect(await readFile(path, 'utf8')).toBe(before)
  })
})

describe('product subagent rows in user presets', () => {
  let productCtx: Context
  const ids = ['products-none', 'products-codex', 'products-claude', 'products-both'] as const

  beforeAll(async () => {
    const root = await mkdtemp(join(tmpdir(), 'dsh-product-presets-'))
    const userRoot = join(root, 'presets')
    const settingsFile = join(root, 'settings.yaml')
    const standard = await readFile(join(CONFIG_DIR, 'agent-presets', 'standard', 'agent.cordis.yml'), 'utf8')
    await writeFile(settingsFile, '{}\n')
    for (const id of ids) {
      let composition = standard
      if (id === 'products-codex' || id === 'products-both') {
        composition = enablePresetTool(composition, 'tool-subagent-codex')
      }
      if (id === 'products-claude' || id === 'products-both') {
        composition = enablePresetTool(composition, 'tool-subagent-claude-code')
      }
      const directory = join(userRoot, id)
      await mkdir(directory, { recursive: true })
      await writeFile(join(directory, 'agent.cordis.yml'), composition)
    }
    productCtx = await bootWeb(settingsFile, [{
      id: 'agent-presets',
      config: {
        default: 'standard',
        roots: [
          { path: join(CONFIG_DIR, 'agent-presets'), trust: 'system' },
          { path: userRoot, trust: 'user' },
        ],
      },
    }])
  }, 120_000)

  afterAll(async () => {
    await productCtx.fiber.dispose()
  })

  it('composes none, either product, or both without changing the shared host registry', async () => {
    const expected = new Map<string, string[]>([
      ['products-none', []],
      ['products-codex', ['subagent_codex']],
      ['products-claude', ['subagent_claude_code']],
      ['products-both', ['subagent_claude_code', 'subagent_codex']],
    ])
    expect(productCtx.subagents.list()).toEqual(expect.arrayContaining([
      'spawn', 'fork', 'codex', 'claude-code',
    ]))

    for (const [id, productTools] of expected) {
      const handle = await productCtx.agents.create({
        sessionId: SessionId(`preset-${id}`),
        setup: agentCtx => productCtx.agentPresets.mount(agentCtx, id).then(() => undefined),
      })
      try {
        const tools = toolNames(productCtx, handle.agent)
        expect(tools.filter(name => name === 'subagent_codex' || name === 'subagent_claude_code'))
          .toEqual(productTools)
      } finally {
        await handle.dispose()
      }
    }
  })

  it('applies a product-row edit only to later sessions on the preset', async () => {
    const preset = await productCtx.agentPresets.resolve('products-none')
    const original = await readFile(preset.path, 'utf8')
    const existing = await productCtx.agents.create({
      sessionId: SessionId('preset-product-generation-existing'),
      setup: agentCtx => productCtx.agentPresets.mount(agentCtx, 'products-none').then(() => undefined),
    })
    try {
      expect(toolNames(productCtx, existing.agent)).not.toContain('subagent_codex')
      await writeFile(preset.path, enablePresetTool(original, 'tool-subagent-codex'))

      const later = await productCtx.agents.create({
        sessionId: SessionId('preset-product-generation-later'),
        setup: agentCtx => productCtx.agentPresets.mount(agentCtx, 'products-none').then(() => undefined),
      })
      try {
        expect(toolNames(productCtx, existing.agent)).not.toContain('subagent_codex')
        expect(toolNames(productCtx, later.agent)).toContain('subagent_codex')
      } finally {
        await later.dispose()
      }
    } finally {
      await existing.dispose()
      await writeFile(preset.path, original)
    }
  })
})

describe('a switch survives the session', () => {
  it('records the choice so the log states what the agent runs', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-switch-logged'),
      meta: { agentPreset: 'standard' },
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    try {
      // The api-proxy's select does exactly this pair while the session is blank.
      await ctx.agentPresets.recompose(handle.agent.ctx, 'minimal')
      handle.agent.session.append('agent-preset/selected', { agentPreset: 'minimal' })

      // The header keeps the creation fact; the log carries what it runs.
      expect(handle.agent.session.header.agentPreset).toBe('standard')
      expect(resolveSessionPreset(handle.agent.session)).toBe('minimal')
    } finally {
      await handle.dispose()
    }
  })

  it('rebuilds a switched session from the log, not the creation header', () => {
    // The exact shape a resume reads back from disk: the header says standard,
    // the log records the switch the user made while the session was blank.
    const rebuilt = resolveSessionPreset({
      header: { version: 0, id: SessionId('x'), createdAt: 0, agentPreset: 'standard' },
      events: [
        { type: 'agent-preset/selected', seq: 1, time: 0, data: { agentPreset: 'minimal' } },
        { type: 'turn/start', seq: 2, time: 0, data: { turn: 0, trigger: { kind: 'message', source: { kind: 'user' } } } },
      ] as never,
    })

    // Reading the header alone would compose the creation-time preset over a
    // history another one produced — the replay the blank-only lock prevents.
    expect(rebuilt).toBe('minimal')
  })
})

describe('a forked session', () => {
  it('inherits the composition its seeded history was produced under', async () => {
    const parent = await ctx.agents.create({
      sessionId: SessionId('preset-fork-parent'),
      meta: { agentPreset: 'minimal' },
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'minimal').then(() => undefined),
    })
    const inherited = resolveSessionPreset(parent.agent.session)
    const child = await ctx.agents.create({
      sessionId: SessionId('preset-fork-child'),
      meta: {
        parentSession: SessionId('preset-fork-parent'),
        seedLength: 0,
        ...inherited === undefined ? {} : { agentPreset: inherited },
      },
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, inherited).then(() => undefined),
    })
    try {
      // Composing nothing would leave the child empty: this layer moved every
      // model-facing row out of the host plane, so there is nothing to inherit
      // for free any more.
      expect(toolNames(ctx, child.agent)).toEqual(toolNames(ctx, parent.agent))
      expect(toolNames(ctx, child.agent).length).toBeGreaterThan(0)
    } finally {
      await child.dispose()
      await parent.dispose()
    }
  })
})

describe('a delegated child', () => {
  it('runs on the composition its parent runs on', async () => {
    const parent = await ctx.agents.create({
      sessionId: SessionId('preset-child-parent'),
      meta: { agentPreset: 'standard' },
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    // Exactly what an in-process subagent driver's creation window does.
    const child = await parent.agent.ctx.agents.create({
      sessionId: SessionId('preset-child'),
      meta: childSessionMeta(parent.agent, 1, 0),
      setup: (agentCtx) => {
        applyChildComposition(agentCtx, parent.agent, {})
      },
    })
    try {
      expect(toolNames(ctx, child.agent)).toEqual(toolNames(ctx, parent.agent))
      // The shipped `standard` preset is the whole coding agent; an empty
      // child here is the defect, and equality alone would not catch it.
      expect(toolNames(ctx, child.agent)).toContain('bash')
      expect(child.agent.session.header.agentPreset).toBe('standard')
    } finally {
      await child.dispose()
      await parent.dispose()
    }
  })

  it('follows a parent that switched preset while blank', async () => {
    const parent = await ctx.agents.create({
      sessionId: SessionId('preset-child-switch-parent'),
      meta: { agentPreset: 'standard' },
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'standard').then(() => undefined),
    })
    await ctx.agentPresets.recompose(parent.agent.ctx, 'minimal')
    const child = await parent.agent.ctx.agents.create({
      sessionId: SessionId('preset-child-switch'),
      meta: childSessionMeta(parent.agent, 1, 0),
      setup: (agentCtx) => {
        applyChildComposition(agentCtx, parent.agent, {})
      },
    })
    try {
      // The live scope chain is the authority, not the parent's creation
      // header — which still names `standard`.
      expect(toolNames(ctx, child.agent)).toEqual(toolNames(ctx, parent.agent))
      expect(child.agent.session.header.agentPreset).toBe('minimal')
    } finally {
      await child.dispose()
      await parent.dispose()
    }
  })
})

describe('authoring a preset on the shipped composition', () => {
  let authorCtx: Context
  let userRoot: string

  beforeAll(async () => {
    userRoot = join(await mkdtemp(join(tmpdir(), 'dsh-preset-authoring-')), 'profiles')
    const settingsFile = join(await mkdtemp(join(tmpdir(), 'dsh-preset-authoring-settings-')), 'settings.yaml')
    await writeFile(settingsFile, '{}\n')
    authorCtx = await bootWeb(settingsFile, [{
      id: 'agent-presets',
      config: {
        default: 'standard',
        roots: [
          { path: join(CONFIG_DIR, 'agent-presets'), trust: 'system' },
          // The root does not exist yet: a deployment whose user has authored
          // nothing is the normal first-run state.
          { path: userRoot, trust: 'user' },
        ],
      },
    }])
  })

  it('refuses to copy over or delete a shipped preset', async () => {
    await expect(authorCtx.agentPresets.copy('minimal', 'standard')).rejects.toThrow(/already exists/)
    await expect(authorCtx.agentPresets.remove('standard')).rejects.toThrow(/ships with the deployment/)
  })

  it.each(['../escape', 'a/b', '/abs', 'Upper'])('refuses the uncontainable id %j', async (id) => {
    // The id becomes a directory name under the user root, so containment is
    // checked on the id rather than on the joined path afterwards.
    await expect(authorCtx.agentPresets.copy('minimal', id)).rejects.toThrow()
  })

  it('copies a shipped preset a session then really composes from', async () => {
    await authorCtx.agentPresets.copy('minimal', 'my-agent', '我的模式')

    // Round-trips through the roster as a `user` row carrying the given name
    // and the source's description, over the source's own composition text.
    const preset = await authorCtx.agentPresets.resolve('my-agent')
    const source = await authorCtx.agentPresets.resolve('minimal')
    expect(preset.trust).toBe('user')
    expect(preset.name).toBe('我的模式')
    expect(preset.description).toBe(source.description)
    expect(await authorCtx.agentPresets.read('my-agent')).toBe(await authorCtx.agentPresets.read('minimal'))
    // Owner-only, in an owner-only directory: a composition is executable
    // configuration on a machine that may have other users.
    expect((await stat(preset.path)).mode & 0o777).toBe(0o600)
    const handle = await authorCtx.agents.create({
      sessionId: SessionId('preset-authored'),
      setup: agentCtx => authorCtx.agentPresets.mount(agentCtx, 'my-agent').then(() => undefined),
    })
    try {
      // The same tools the shipped `minimal` composes, from a directory copied
      // through the service into a root outside the installed harness.
      expect(toolNames(authorCtx, handle.agent)).toEqual(['bash', 'str_replace_editor'])
    } finally {
      await handle.dispose()
    }
  })

  it('deletes what it copied', async () => {
    await authorCtx.agentPresets.copy('minimal', 'doomed')

    await authorCtx.agentPresets.remove('doomed')

    expect((await authorCtx.agentPresets.list()).map(preset => preset.id)).not.toContain('doomed')
  })
})

/**
 * Which preset an unnamed session gets is a user setting layered over the
 * composition's own default. The package suite proves the layering against a
 * hand-built context; this proves it through the shipped `cordis.yml` — that
 * the roster and the settings provider are actually wired to each other, and
 * that the id the setting names is the one a session composes from.
 */
describe('the default preset as a user setting', () => {
  it('composes an unnamed session from the stored default, not the composed one', async () => {
    expect(ctx.agentPresets.defaultId).toBe('standard')

    await ctx.settings.update(settingsNamespace(SETTINGS_NAMESPACE), { default: 'minimal' })
    try {
      expect(ctx.agentPresets.defaultId).toBe('minimal')

      const handle = await ctx.agents.create({
        sessionId: SessionId('preset-user-default'),
        setup: agentCtx => ctx.agentPresets.mount(agentCtx).then(() => undefined),
      })
      try {
        // `mount()` with no id resolves the effective default. Two tools, not
        // `standard`'s catalog: the setting decided the composition.
        expect(toolNames(ctx, handle.agent)).toEqual(['bash', 'str_replace_editor'])
      } finally {
        await handle.dispose()
      }
    } finally {
      // The context is shared with the rest of the file. `replace({})` drops
      // the user section wholesale so the field re-inherits the composition
      // base; `update` merges, and would leave the override standing.
      await ctx.settings.replace(settingsNamespace(SETTINGS_NAMESPACE), {})
    }

    expect(ctx.agentPresets.defaultId).toBe('standard')
  })
})

describe('a session keeps the preset it was created with', () => {
  it('refuses to adopt a live session under a different preset', async () => {
    const handle = await ctx.agents.create({
      sessionId: SessionId('preset-locked'),
      meta: { agentPreset: 'minimal' },
      setup: agentCtx => ctx.agentPresets.mount(agentCtx, 'minimal').then(() => undefined),
    })
    try {
      // The api-proxy guard reads exactly this: the header records what the
      // session runs, so naming anything else is a caller error rather than a
      // switch. Its history was produced under `minimal`'s two tools.
      expect(handle.agent.session.header.agentPreset).toBe('minimal')
    } finally {
      await handle.dispose()
    }
  })
})