diff --git a/packages/coord/package.json b/packages/coord/package.json
new file mode 100644
index 0000000..751402a
--- /dev/null
+++ b/packages/coord/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "@mosaic/coord",
+  "version": "0.1.0",
+  "type": "module",
+  "description": "Mosaic mission coordination — TypeScript rewrite of mosaic coord",
+  "scripts": {
+    "build": "tsc -p tsconfig.json",
+    "typecheck": "tsc --noEmit",
+    "lint": "echo 'ok'",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "@mosaic/queue": "workspace:*",
+    "@mosaic/types": "workspace:*",
+    "commander": "^13",
+    "js-yaml": "^4"
+  },
+  "devDependencies": {
+    "@types/js-yaml": "^4",
+    "@types/node": "^22",
+    "typescript": "^5",
+    "vitest": "^2"
+  }
+}
diff --git a/packages/coord/src/cli.ts b/packages/coord/src/cli.ts
new file mode 100644
index 0000000..e79f4fc
--- /dev/null
+++ b/packages/coord/src/cli.ts
@@ -0,0 +1,155 @@
+import { Command } from 'commander';
+
+import { createMission, loadMission } from './mission.js';
+import { runTask, resumeTask } from './runner.js';
+import { getMissionStatus } from './status.js';
+import type { MissionStatusSummary } from './types.js';
+
+interface InitCommandOptions {
+  readonly name: string;
+  readonly project?: string;
+  readonly prefix?: string;
+  readonly milestones?: string;
+  readonly qualityGates?: string;
+  readonly version?: string;
+  readonly description?: string;
+  readonly force?: boolean;
+}
+
+interface RunCommandOptions {
+  readonly project: string;
+  readonly task: string;
+  readonly runtime?: 'claude' | 'codex';
+  readonly print?: boolean;
+}
+
+interface StatusCommandOptions {
+  readonly project: string;
+  readonly format?: 'json' | 'table';
+}
+
+function parseMilestones(value: string | undefined): string[] {
+  if (value === undefined || value.trim().length === 0) {
+    return [];
+  }
+
+  return value
+    .split(',')
+    .map((entry) => entry.trim())
+    .filter((entry) => entry.length > 0);
+}
+
+function renderStatusTable(status: MissionStatusSummary): string {
+  const lines = [
+    `Mission: ${status.mission.name} (${status.mission.id})`,
+    `Status: ${status.mission.status}`,
+    `Project: ${status.mission.projectPath}`,
+    `Milestones: ${status.milestones.completed}/${status.milestones.total} completed`,
+    `Tasks: total=${status.tasks.total}, done=${status.tasks.done}, in-progress=${status.tasks.inProgress}, pending=${status.tasks.pending}, blocked=${status.tasks.blocked}, cancelled=${status.tasks.cancelled}`,
+    `Next task: ${status.nextTaskId ?? '—'}`,
+    `Active session: ${status.activeSession?.sessionId ?? 'none'}`,
+  ];
+
+  return lines.join('\n');
+}
+
+export function buildCoordCli(): Command {
+  const program = new Command();
+  program
+    .name('mosaic')
+    .description('Mosaic CLI')
+    .exitOverride();
+
+  const coord = program.command('coord').description('Mission coordination commands');
+
+  coord
+    .command('init')
+    .description('Initialize orchestrator mission state')
+    .requiredOption('--name <name>', 'Mission name')
+    .option('--project <path>', 'Project path')
+    .option('--prefix <prefix>', 'Task prefix')
+    .option('--milestones <comma-separated>', 'Milestone names')
+    .option('--quality-gates <command>', 'Quality gate command')
+    .option('--version <semver>', 'Milestone version')
+    .option('--description <description>', 'Mission description')
+    .option('--force', 'Overwrite active mission')
+    .action(async (options: InitCommandOptions) => {
+      const mission = await createMission({
+        name: options.name,
+        projectPath: options.project,
+        prefix: options.prefix,
+        milestones: parseMilestones(options.milestones),
+        qualityGates: options.qualityGates,
+        version: options.version,
+        description: options.description,
+        force: options.force,
+      });
+
+      console.log(
+        JSON.stringify(
+          {
+            ok: true,
+            missionId: mission.id,
+            projectPath: mission.projectPath,
+          },
+          null,
+          2,
+        ),
+      );
+    });
+
+  coord
+    .command('run')
+    .description('Run a mission task')
+    .requiredOption('--project <path>', 'Project path')
+    .requiredOption('--task <id>', 'Task id')
+    .option('--runtime <runtime>', 'Runtime (claude|codex)')
+    .option('--print', 'Print launch command only')
+    .action(async (options: RunCommandOptions) => {
+      const mission = await loadMission(options.project);
+      const run = await runTask(mission, options.task, {
+        runtime: options.runtime,
+        mode: options.print === true ? 'print-only' : 'interactive',
+      });
+      console.log(JSON.stringify(run, null, 2));
+    });
+
+  coord
+    .command('resume')
+    .description('Resume a mission task after stale/dead session lock')
+    .requiredOption('--project <path>', 'Project path')
+    .requiredOption('--task <id>', 'Task id')
+    .option('--runtime <runtime>', 'Runtime (claude|codex)')
+    .option('--print', 'Print launch command only')
+    .action(async (options: RunCommandOptions) => {
+      const mission = await loadMission(options.project);
+      const run = await resumeTask(mission, options.task, {
+        runtime: options.runtime,
+        mode: options.print === true ? 'print-only' : 'interactive',
+      });
+      console.log(JSON.stringify(run, null, 2));
+    });
+
+  coord
+    .command('status')
+    .description('Show mission status')
+    .requiredOption('--project <path>', 'Project path')
+    .option('--format <format>', 'Output format (table|json)', 'table')
+    .action(async (options: StatusCommandOptions) => {
+      const mission = await loadMission(options.project);
+      const status = await getMissionStatus(mission);
+
+      if (options.format === 'json') {
+        console.log(JSON.stringify(status, null, 2));
+      } else {
+        console.log(renderStatusTable(status));
+      }
+    });
+
+  return program;
+}
+
+export async function runCoordCli(argv: readonly string[] = process.argv): Promise<void> {
+  const program = buildCoordCli();
+  await program.parseAsync(argv);
+}
diff --git a/packages/coord/src/index.ts b/packages/coord/src/index.ts
new file mode 100644
index 0000000..d4a0700
--- /dev/null
+++ b/packages/coord/src/index.ts
@@ -0,0 +1,34 @@
+export {
+  createMission,
+  loadMission,
+  missionFilePath,
+  saveMission,
+} from './mission.js';
+export {
+  parseTasksFile,
+  updateTaskStatus,
+  writeTasksFile,
+} from './tasks-file.js';
+export { runTask, resumeTask } from './runner.js';
+export { getMissionStatus, getTaskStatus } from './status.js';
+export { buildCoordCli, runCoordCli } from './cli.js';
+export type {
+  CreateMissionOptions,
+  Mission,
+  MissionMilestone,
+  MissionRuntime,
+  MissionSession,
+  MissionStatus,
+  MissionStatusSummary,
+  MissionTask,
+  NextTaskCapsule,
+  RunTaskOptions,
+  TaskDetail,
+  TaskRun,
+  TaskStatus,
+} from './types.js';
+export {
+  isMissionStatus,
+  isTaskStatus,
+  normalizeTaskStatus,
+} from './types.js';
diff --git a/packages/coord/src/mission.ts b/packages/coord/src/mission.ts
new file mode 100644
index 0000000..a93b10a
--- /dev/null
+++ b/packages/coord/src/mission.ts
@@ -0,0 +1,415 @@
+import { promises as fs } from 'node:fs';
+import path from 'node:path';
+
+import { writeTasksFile } from './tasks-file.js';
+import type {
+  CreateMissionOptions,
+  Mission,
+  MissionMilestone,
+  MissionSession,
+} from './types.js';
+import { isMissionStatus } from './types.js';
+
+const DEFAULT_ORCHESTRATOR_DIR = '.mosaic/orchestrator';
+const DEFAULT_MISSION_FILE = 'mission.json';
+const DEFAULT_TASKS_FILE = 'docs/TASKS.md';
+const DEFAULT_MANIFEST_FILE = 'docs/MISSION-MANIFEST.md';
+const DEFAULT_SCRATCHPAD_DIR = 'docs/scratchpads';
+const DEFAULT_MILESTONE_VERSION = '0.0.1';
+
+function asRecord(value: unknown): Record<string, unknown> {
+  if (typeof value === 'object' && value !== null) {
+    return value as Record<string, unknown>;
+  }
+
+  return {};
+}
+
+function readString(
+  source: Record<string, unknown>,
+  ...keys: readonly string[]
+): string | undefined {
+  for (const key of keys) {
+    const value = source[key];
+    if (typeof value === 'string') {
+      const trimmed = value.trim();
+      if (trimmed.length > 0) {
+        return trimmed;
+      }
+    }
+  }
+
+  return undefined;
+}
+
+function readNumber(
+  source: Record<string, unknown>,
+  ...keys: readonly string[]
+): number | undefined {
+  for (const key of keys) {
+    const value = source[key];
+    if (typeof value === 'number' && Number.isFinite(value)) {
+      return value;
+    }
+  }
+
+  return undefined;
+}
+
+function normalizeMilestoneStatus(status: string | undefined): MissionMilestone['status'] {
+  if (status === 'completed') {
+    return 'completed';
+  }
+
+  if (status === 'in-progress') {
+    return 'in-progress';
+  }
+
+  if (status === 'blocked') {
+    return 'blocked';
+  }
+
+  return 'pending';
+}
+
+function normalizeSessionRuntime(runtime: string | undefined): MissionSession['runtime'] {
+  if (runtime === 'claude' || runtime === 'codex' || runtime === 'unknown') {
+    return runtime;
+  }
+
+  return 'unknown';
+}
+
+function normalizeEndedReason(reason: string | undefined): MissionSession['endedReason'] {
+  if (
+    reason === 'completed' ||
+    reason === 'paused' ||
+    reason === 'crashed' ||
+    reason === 'killed' ||
+    reason === 'unknown'
+  ) {
+    return reason;
+  }
+
+  return undefined;
+}
+
+function normalizeMission(raw: unknown, resolvedProjectPath: string): Mission {
+  const source = asRecord(raw);
+
+  const id = readString(source, 'id', 'mission_id') ?? 'mission';
+  const name = readString(source, 'name') ?? 'Unnamed Mission';
+  const statusCandidate = readString(source, 'status') ?? 'inactive';
+  const status = isMissionStatus(statusCandidate) ? statusCandidate : 'inactive';
+
+  const mission: Mission = {
+    schemaVersion: 1,
+    id,
+    name,
+    description: readString(source, 'description'),
+    projectPath:
+      readString(source, 'projectPath', 'project_path') ?? resolvedProjectPath,
+    createdAt:
+      readString(source, 'createdAt', 'created_at') ?? new Date().toISOString(),
+    status,
+    tasksFile: readString(source, 'tasksFile', 'tasks_file') ?? DEFAULT_TASKS_FILE,
+    manifestFile:
+      readString(source, 'manifestFile', 'manifest_file') ?? DEFAULT_MANIFEST_FILE,
+    scratchpadFile:
+      readString(source, 'scratchpadFile', 'scratchpad_file') ??
+      `${DEFAULT_SCRATCHPAD_DIR}/${id}.md`,
+    orchestratorDir:
+      readString(source, 'orchestratorDir', 'orchestrator_dir') ??
+      DEFAULT_ORCHESTRATOR_DIR,
+    taskPrefix: readString(source, 'taskPrefix', 'task_prefix'),
+    qualityGates: readString(source, 'qualityGates', 'quality_gates'),
+    milestoneVersion: readString(source, 'milestoneVersion', 'milestone_version'),
+    milestones: [],
+    sessions: [],
+  };
+
+  const milestonesRaw = Array.isArray(source.milestones) ? source.milestones : [];
+  mission.milestones = milestonesRaw.map((milestoneValue, index) => {
+    const milestone = asRecord(milestoneValue);
+    return {
+      id: readString(milestone, 'id') ?? `phase-${index + 1}`,
+      name: readString(milestone, 'name') ?? `Phase ${index + 1}`,
+      status: normalizeMilestoneStatus(readString(milestone, 'status')),
+      branch: readString(milestone, 'branch'),
+      issueRef: readString(milestone, 'issueRef', 'issue_ref'),
+      startedAt: readString(milestone, 'startedAt', 'started_at'),
+      completedAt: readString(milestone, 'completedAt', 'completed_at'),
+    };
+  });
+
+  const sessionsRaw = Array.isArray(source.sessions) ? source.sessions : [];
+  mission.sessions = sessionsRaw.map((sessionValue, index) => {
+    const session = asRecord(sessionValue);
+    const fallbackSessionId = `sess-${String(index + 1).padStart(3, '0')}`;
+
+    return {
+      sessionId: readString(session, 'sessionId', 'session_id') ?? fallbackSessionId,
+      runtime: normalizeSessionRuntime(readString(session, 'runtime')),
+      pid: readNumber(session, 'pid'),
+      startedAt:
+        readString(session, 'startedAt', 'started_at') ?? mission.createdAt,
+      endedAt: readString(session, 'endedAt', 'ended_at'),
+      endedReason: normalizeEndedReason(
+        readString(session, 'endedReason', 'ended_reason'),
+      ),
+      milestoneId: readString(session, 'milestoneId', 'milestone_id'),
+      lastTaskId: readString(session, 'lastTaskId', 'last_task_id'),
+      durationSeconds: readNumber(session, 'durationSeconds', 'duration_seconds'),
+    };
+  });
+
+  return mission;
+}
+
+function missionIdFromName(name: string): string {
+  const slug = name
+    .toLowerCase()
+    .replace(/[^a-z0-9]+/g, '-')
+    .replace(/^-+|-+$/g, '')
+    .replace(/-{2,}/g, '-');
+  const date = new Date().toISOString().slice(0, 10).replace(/-/g, '');
+  return `${slug || 'mission'}-${date}`;
+}
+
+function toAbsolutePath(basePath: string, targetPath: string): string {
+  if (path.isAbsolute(targetPath)) {
+    return targetPath;
+  }
+
+  return path.join(basePath, targetPath);
+}
+
+function isNodeErrorWithCode(error: unknown, code: string): boolean {
+  return (
+    typeof error === 'object' &&
+    error !== null &&
+    'code' in error &&
+    (error as { code?: string }).code === code
+  );
+}
+
+async function fileExists(filePath: string): Promise<boolean> {
+  try {
+    await fs.access(filePath);
+    return true;
+  } catch (error) {
+    if (isNodeErrorWithCode(error, 'ENOENT')) {
+      return false;
+    }
+    throw error;
+  }
+}
+
+async function writeFileAtomic(filePath: string, content: string): Promise<void> {
+  const directory = path.dirname(filePath);
+  await fs.mkdir(directory, { recursive: true });
+
+  const tempPath = path.join(
+    directory,
+    `.${path.basename(filePath)}.tmp-${process.pid}-${Date.now()}-${Math.random()
+      .toString(16)
+      .slice(2)}`,
+  );
+
+  await fs.writeFile(tempPath, content, 'utf8');
+  await fs.rename(tempPath, filePath);
+}
+
+function renderManifest(mission: Mission): string {
+  const milestoneRows = mission.milestones
+    .map((milestone, index) => {
+      const issue = milestone.issueRef ?? '—';
+      const branch = milestone.branch ?? '—';
+      const started = milestone.startedAt ?? '—';
+      const completed = milestone.completedAt ?? '—';
+      return `| ${index + 1} | ${milestone.id} | ${milestone.name} | ${milestone.status} | ${branch} | ${issue} | ${started} | ${completed} |`;
+    })
+    .join('\n');
+
+  const body = [
+    `# Mission Manifest — ${mission.name}`,
+    '',
+    '> Persistent document tracking full mission scope, status, and session history.',
+    '',
+    '## Mission',
+    '',
+    `**ID:** ${mission.id}`,
+    `**Statement:** ${mission.description ?? ''}`,
+    '**Phase:** Intake',
+    '**Current Milestone:** —',
+    `**Progress:** 0 / ${mission.milestones.length} milestones`,
+    `**Status:** ${mission.status}`,
+    `**Last Updated:** ${new Date().toISOString().replace('T', ' ').replace(/\..+/, ' UTC')}`,
+    '',
+    '## Milestones',
+    '',
+    '| # | ID | Name | Status | Branch | Issue | Started | Completed |',
+    '|---|-----|------|--------|--------|-------|---------|-----------|',
+    milestoneRows,
+    '',
+    '## Session History',
+    '',
+    '| Session | Runtime | Started | Duration | Ended Reason | Last Task |',
+    '|---------|---------|---------|----------|--------------|-----------|',
+    '',
+    `## Scratchpad\n\nPath: \`${mission.scratchpadFile}\``,
+    '',
+  ];
+
+  return body.join('\n');
+}
+
+function renderScratchpad(mission: Mission): string {
+  return [
+    `# Mission Scratchpad — ${mission.name}`,
+    '',
+    '> Append-only log. NEVER delete entries. NEVER overwrite sections.',
+    '',
+    '## Original Mission Prompt',
+    '',
+    '```',
+    '(Paste the mission prompt here on first session)',
+    '```',
+    '',
+    '## Planning Decisions',
+    '',
+    '## Session Log',
+    '',
+    '| Session | Date | Milestone | Tasks Done | Outcome |',
+    '|---------|------|-----------|------------|---------|',
+    '',
+    '## Open Questions',
+    '',
+    '## Corrections',
+    '',
+  ].join('\n');
+}
+
+function buildMissionFromOptions(
+  options: CreateMissionOptions,
+  resolvedProjectPath: string,
+): Mission {
+  const id = missionIdFromName(options.name);
+  const createdAt = new Date().toISOString();
+
+  const milestones = (options.milestones ?? []).map((name, index) => {
+    const cleanName = name.trim();
+    const milestoneName = cleanName.length > 0 ? cleanName : `Phase ${index + 1}`;
+    return {
+      id: `phase-${index + 1}`,
+      name: milestoneName,
+      status: 'pending' as const,
+      branch: milestoneName
+        .toLowerCase()
+        .replace(/[^a-z0-9]+/g, '-')
+        .replace(/^-+|-+$/g, ''),
+      issueRef: undefined,
+      startedAt: undefined,
+      completedAt: undefined,
+    };
+  });
+
+  return {
+    schemaVersion: 1,
+    id,
+    name: options.name,
+    description: options.description,
+    projectPath: resolvedProjectPath,
+    createdAt,
+    status: 'active',
+    tasksFile: DEFAULT_TASKS_FILE,
+    manifestFile: DEFAULT_MANIFEST_FILE,
+    scratchpadFile: `${DEFAULT_SCRATCHPAD_DIR}/${id}.md`,
+    orchestratorDir: DEFAULT_ORCHESTRATOR_DIR,
+    taskPrefix: options.prefix,
+    qualityGates: options.qualityGates,
+    milestoneVersion: options.version ?? DEFAULT_MILESTONE_VERSION,
+    milestones,
+    sessions: [],
+  };
+}
+
+export function missionFilePath(projectPath: string, mission?: Mission): string {
+  const orchestratorDir = mission?.orchestratorDir ?? DEFAULT_ORCHESTRATOR_DIR;
+  const baseDir = path.isAbsolute(orchestratorDir)
+    ? orchestratorDir
+    : path.join(projectPath, orchestratorDir);
+  return path.join(baseDir, DEFAULT_MISSION_FILE);
+}
+
+export async function saveMission(mission: Mission): Promise<void> {
+  const filePath = missionFilePath(mission.projectPath, mission);
+  const payload = `${JSON.stringify(mission, null, 2)}\n`;
+  await writeFileAtomic(filePath, payload);
+}
+
+export async function createMission(options: CreateMissionOptions): Promise<Mission> {
+  const name = options.name.trim();
+  if (name.length === 0) {
+    throw new Error('Mission name is required');
+  }
+
+  const resolvedProjectPath = path.resolve(options.projectPath ?? process.cwd());
+  const mission = buildMissionFromOptions({ ...options, name }, resolvedProjectPath);
+
+  const missionPath = missionFilePath(resolvedProjectPath, mission);
+  const hasExistingMission = await fileExists(missionPath);
+
+  if (hasExistingMission) {
+    const existingRaw = await fs.readFile(missionPath, 'utf8');
+    const existingMission = normalizeMission(JSON.parse(existingRaw), resolvedProjectPath);
+    const active = existingMission.status === 'active' || existingMission.status === 'paused';
+    if (active && options.force !== true) {
+      throw new Error(
+        `Active mission exists: ${existingMission.name} (${existingMission.status}). Use force to overwrite.`,
+      );
+    }
+  }
+
+  await saveMission(mission);
+
+  const manifestPath = toAbsolutePath(resolvedProjectPath, mission.manifestFile);
+  const scratchpadPath = toAbsolutePath(resolvedProjectPath, mission.scratchpadFile);
+  const tasksPath = toAbsolutePath(resolvedProjectPath, mission.tasksFile);
+
+  if (options.force === true || !(await fileExists(manifestPath))) {
+    await writeFileAtomic(manifestPath, renderManifest(mission));
+  }
+
+  if (!(await fileExists(scratchpadPath))) {
+    await writeFileAtomic(scratchpadPath, renderScratchpad(mission));
+  }
+
+  if (!(await fileExists(tasksPath))) {
+    await writeFileAtomic(tasksPath, writeTasksFile([]));
+  }
+
+  return mission;
+}
+
+export async function loadMission(projectPath: string): Promise<Mission> {
+  const resolvedProjectPath = path.resolve(projectPath);
+  const filePath = missionFilePath(resolvedProjectPath);
+
+  let raw: string;
+  try {
+    raw = await fs.readFile(filePath, 'utf8');
+  } catch (error) {
+    if (isNodeErrorWithCode(error, 'ENOENT')) {
+      throw new Error(`No mission found at ${filePath}`);
+    }
+    throw error;
+  }
+
+  const mission = normalizeMission(JSON.parse(raw), resolvedProjectPath);
+  if (mission.status === 'inactive') {
+    throw new Error('Mission exists but is inactive. Re-initialize with mosaic coord init.');
+  }
+
+  return mission;
+}
diff --git a/packages/coord/src/runner.ts b/packages/coord/src/runner.ts
new file mode 100644
index 0000000..5185db2
--- /dev/null
+++ b/packages/coord/src/runner.ts
@@ -0,0 +1,488 @@
+import { spawn, spawnSync } from 'node:child_process';
+import { promises as fs } from 'node:fs';
+import path from 'node:path';
+
+import { loadMission, saveMission } from './mission.js';
+import { parseTasksFile, updateTaskStatus } from './tasks-file.js';
+import type {
+  Mission,
+  MissionMilestone,
+  MissionSession,
+  RunTaskOptions,
+  TaskRun,
+} from './types.js';
+
+const SESSION_LOCK_FILE = 'session.lock';
+const NEXT_TASK_FILE = 'next-task.json';
+
+interface SessionLockState {
+  session_id: string;
+  runtime: 'claude' | 'codex';
+  pid: number;
+  started_at: string;
+  project_path: string;
+  milestone_id?: string;
+}
+
+function orchestratorDirPath(mission: Mission): string {
+  if (path.isAbsolute(mission.orchestratorDir)) {
+    return mission.orchestratorDir;
+  }
+
+  return path.join(mission.projectPath, mission.orchestratorDir);
+}
+
+function sessionLockPath(mission: Mission): string {
+  return path.join(orchestratorDirPath(mission), SESSION_LOCK_FILE);
+}
+
+function nextTaskCapsulePath(mission: Mission): string {
+  return path.join(orchestratorDirPath(mission), NEXT_TASK_FILE);
+}
+
+function tasksFilePath(mission: Mission): string {
+  if (path.isAbsolute(mission.tasksFile)) {
+    return mission.tasksFile;
+  }
+
+  return path.join(mission.projectPath, mission.tasksFile);
+}
+
+function buildSessionId(mission: Mission): string {
+  return `sess-${String(mission.sessions.length + 1).padStart(3, '0')}`;
+}
+
+function isPidAlive(pid: number): boolean {
+  try {
+    process.kill(pid, 0);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+function currentMilestone(mission: Mission): MissionMilestone | undefined {
+  return mission.milestones.find((milestone) => milestone.status === 'in-progress')
+    ?? mission.milestones.find((milestone) => milestone.status === 'pending');
+}
+
+async function readTasks(mission: Mission) {
+  const filePath = tasksFilePath(mission);
+
+  try {
+    const content = await fs.readFile(filePath, 'utf8');
+    return parseTasksFile(content);
+  } catch (error) {
+    if (
+      typeof error === 'object' &&
+      error !== null &&
+      'code' in error &&
+      (error as { code?: string }).code === 'ENOENT'
+    ) {
+      return [];
+    }
+
+    throw error;
+  }
+}
+
+function currentBranch(projectPath: string): string | undefined {
+  const result = spawnSync('git', ['-C', projectPath, 'branch', '--show-current'], {
+    encoding: 'utf8',
+  });
+
+  if (result.status !== 0) {
+    return undefined;
+  }
+
+  const branch = result.stdout.trim();
+  return branch.length > 0 ? branch : undefined;
+}
+
+function percentage(done: number, total: number): number {
+  if (total === 0) {
+    return 0;
+  }
+
+  return Math.floor((done / total) * 100);
+}
+
+function formatDurationSeconds(totalSeconds: number): string {
+  if (totalSeconds < 60) {
+    return `${totalSeconds}s`;
+  }
+
+  if (totalSeconds < 3600) {
+    const minutes = Math.floor(totalSeconds / 60);
+    const seconds = totalSeconds % 60;
+    return `${minutes}m ${seconds}s`;
+  }
+
+  const hours = Math.floor(totalSeconds / 3600);
+  const minutes = Math.floor((totalSeconds % 3600) / 60);
+  return `${hours}h ${minutes}m`;
+}
+
+function buildContinuationPrompt(params: {
+  mission: Mission;
+  taskId: string;
+  runtime: 'claude' | 'codex';
+  tasksDone: number;
+  tasksTotal: number;
+  currentMilestone?: MissionMilestone;
+  previousSession?: MissionSession;
+  branch?: string;
+}): string {
+  const {
+    mission,
+    taskId,
+    runtime,
+    tasksDone,
+    tasksTotal,
+    currentMilestone,
+    previousSession,
+    branch,
+  } = params;
+
+  const pct = percentage(tasksDone, tasksTotal);
+  const previousDuration =
+    previousSession?.durationSeconds !== undefined
+      ? formatDurationSeconds(previousSession.durationSeconds)
+      : '—';
+
+  return [
+    '## Continuation Mission',
+    '',
+    `Continue **${mission.name}** from existing state.`,
+    '',
+    '## Setup',
+    '',
+    `- **Project:** ${mission.projectPath}`,
+    `- **State:** ${mission.tasksFile} (${tasksDone}/${tasksTotal} tasks complete)`,
+    `- **Manifest:** ${mission.manifestFile}`,
+    `- **Scratchpad:** ${mission.scratchpadFile}`,
+    '- **Protocol:** ~/.config/mosaic/guides/ORCHESTRATOR.md',
+    `- **Quality gates:** ${mission.qualityGates ?? '—'}`,
+    `- **Target runtime:** ${runtime}`,
+    '',
+    '## Resume Point',
+    '',
+    `- **Current milestone:** ${currentMilestone?.name ?? '—'} (${currentMilestone?.id ?? '—'})`,
+    `- **Next task:** ${taskId}`,
+    `- **Progress:** ${tasksDone}/${tasksTotal} (${pct}%)`,
+    `- **Branch:** ${branch ?? '—'}`,
+    '',
+    '## Previous Session Context',
+    '',
+    `- **Session:** ${previousSession?.sessionId ?? '—'} (${previousSession?.runtime ?? '—'}, ${previousDuration})`,
+    `- **Ended:** ${previousSession?.endedReason ?? '—'}`,
+    `- **Last completed task:** ${previousSession?.lastTaskId ?? '—'}`,
+    '',
+    '## Instructions',
+    '',
+    '1. Read `~/.config/mosaic/guides/ORCHESTRATOR.md` for full protocol',
+    `2. Read \`${mission.manifestFile}\` for mission scope and status`,
+    `3. Read \`${mission.scratchpadFile}\` for session history and decisions`,
+    `4. Read \`${mission.tasksFile}\` for current task state`,
+    '5. `git pull --rebase` to sync latest changes',
+    `6. Launch runtime with \`${runtime} -p\``,
+    `7. Continue execution from task **${taskId}**`,
+    '8. Follow Two-Phase Completion Protocol',
+    `9. You are the SOLE writer of \`${mission.tasksFile}\``,
+  ].join('\n');
+}
+
+function resolveLaunchCommand(
+  runtime: 'claude' | 'codex',
+  prompt: string,
+  configuredCommand: string[] | undefined,
+): string[] {
+  if (configuredCommand === undefined || configuredCommand.length === 0) {
+    return [runtime, '-p', prompt];
+  }
+
+  const withInterpolation = configuredCommand.map((value) =>
+    value === '{prompt}' ? prompt : value,
+  );
+
+  if (withInterpolation.includes(prompt)) {
+    return withInterpolation;
+  }
+
+  return [...withInterpolation, prompt];
+}
+
+async function writeAtomicJson(filePath: string, payload: unknown): Promise<void> {
+  const directory = path.dirname(filePath);
+  await fs.mkdir(directory, { recursive: true });
+
+  const tempPath = path.join(
+    directory,
+    `.${path.basename(filePath)}.tmp-${process.pid}-${Date.now()}-${Math.random()
+      .toString(16)
+      .slice(2)}`,
+  );
+
+  await fs.writeFile(tempPath, `${JSON.stringify(payload, null, 2)}\n`, 'utf8');
+  await fs.rename(tempPath, filePath);
+}
+
+async function readSessionLock(mission: Mission): Promise<SessionLockState | undefined> {
+  const filePath = sessionLockPath(mission);
+
+  try {
+    const raw = await fs.readFile(filePath, 'utf8');
+    const data = JSON.parse(raw) as Partial<SessionLockState>;
+
+    if (
+      typeof data.session_id !== 'string' ||
+      (data.runtime !== 'claude' && data.runtime !== 'codex') ||
+      typeof data.pid !== 'number' ||
+      typeof data.started_at !== 'string' ||
+      typeof data.project_path !== 'string'
+    ) {
+      return undefined;
+    }
+
+    return {
+      session_id: data.session_id,
+      runtime: data.runtime,
+      pid: data.pid,
+      started_at: data.started_at,
+      project_path: data.project_path,
+      milestone_id: data.milestone_id,
+    };
+  } catch (error) {
+    if (
+      typeof error === 'object' &&
+      error !== null &&
+      'code' in error &&
+      (error as { code?: string }).code === 'ENOENT'
+    ) {
+      return undefined;
+    }
+
+    throw error;
+  }
+}
+
+async function writeSessionLock(
+  mission: Mission,
+  lock: SessionLockState,
+): Promise<void> {
+  await writeAtomicJson(sessionLockPath(mission), lock);
+}
+
+function markSessionCrashed(
+  mission: Mission,
+  sessionId: string,
+  endedAt: string,
+): Mission {
+  const sessions = mission.sessions.map((session) => {
+    if (session.sessionId !== sessionId) {
+      return session;
+    }
+
+    if (session.endedAt !== undefined) {
+      return session;
+    }
+
+    const startedEpoch = Date.parse(session.startedAt);
+    const endedEpoch = Date.parse(endedAt);
+    const durationSeconds =
+      Number.isFinite(startedEpoch) && Number.isFinite(endedEpoch)
+        ? Math.max(0, Math.floor((endedEpoch - startedEpoch) / 1000))
+        : undefined;
+
+    return {
+      ...session,
+      endedAt,
+      endedReason: 'crashed' as const,
+      durationSeconds,
+    };
+  });
+
+  return {
+    ...mission,
+    sessions,
+  };
+}
+
+export async function runTask(
+  mission: Mission,
+  taskId: string,
+  options: RunTaskOptions = {},
+): Promise<TaskRun> {
+  const runtime = options.runtime ?? 'claude';
+  const mode = options.mode ?? 'interactive';
+
+  const freshMission = await loadMission(mission.projectPath);
+  const tasks = await readTasks(freshMission);
+  const matches = tasks.filter((task) => task.id === taskId);
+
+  if (matches.length === 0) {
+    throw new Error(`Task not found: ${taskId}`);
+  }
+
+  if (matches.length > 1) {
+    throw new Error(`Duplicate task IDs found: ${taskId}`);
+  }
+
+  const task = matches[0];
+  if (task.status === 'done' || task.status === 'cancelled') {
+    throw new Error(`Task ${taskId} cannot be run from status ${task.status}`);
+  }
+
+  const tasksTotal = tasks.length;
+  const tasksDone = tasks.filter((candidate) => candidate.status === 'done').length;
+  const selectedMilestone =
+    freshMission.milestones.find((milestone) => milestone.id === options.milestoneId)
+    ?? freshMission.milestones.find((milestone) => milestone.id === task.milestone)
+    ?? currentMilestone(freshMission);
+
+  const continuationPrompt = buildContinuationPrompt({
+    mission: freshMission,
+    taskId,
+    runtime,
+    tasksDone,
+    tasksTotal,
+    currentMilestone: selectedMilestone,
+    previousSession: freshMission.sessions.at(-1),
+    branch: currentBranch(freshMission.projectPath),
+  });
+
+  const launchCommand = resolveLaunchCommand(runtime, continuationPrompt, options.command);
+  const startedAt = new Date().toISOString();
+  const sessionId = buildSessionId(freshMission);
+  const lockFile = sessionLockPath(freshMission);
+
+  await writeAtomicJson(nextTaskCapsulePath(freshMission), {
+    generated_at: startedAt,
+    runtime,
+    mission_id: freshMission.id,
+    mission_name: freshMission.name,
+    project_path: freshMission.projectPath,
+    quality_gates: freshMission.qualityGates ?? '',
+    current_milestone: {
+      id: selectedMilestone?.id ?? '',
+      name: selectedMilestone?.name ?? '',
+    },
+    next_task: taskId,
+    progress: {
+      tasks_done: tasksDone,
+      tasks_total: tasksTotal,
+      pct: percentage(tasksDone, tasksTotal),
+    },
+    current_branch: currentBranch(freshMission.projectPath) ?? '',
+  });
+
+  if (mode === 'print-only') {
+    return {
+      missionId: freshMission.id,
+      taskId,
+      sessionId,
+      runtime,
+      launchCommand,
+      startedAt,
+      lockFile,
+    };
+  }
+
+  await updateTaskStatus(freshMission, taskId, 'in-progress');
+
+  await writeSessionLock(freshMission, {
+    session_id: sessionId,
+    runtime,
+    pid: 0,
+    started_at: startedAt,
+    project_path: freshMission.projectPath,
+    milestone_id: selectedMilestone?.id,
+  });
+
+  const child = spawn(launchCommand[0], launchCommand.slice(1), {
+    cwd: freshMission.projectPath,
+    env: {
+      ...process.env,
+      ...(options.env ?? {}),
+    },
+    stdio: 'inherit',
+  });
+
+  await new Promise<void>((resolve, reject) => {
+    child.once('spawn', () => {
+      resolve();
+    });
+    child.once('error', (error) => {
+      reject(error);
+    });
+  });
+
+  const pid = child.pid;
+  if (pid === undefined) {
+    throw new Error('Failed to start task runtime process (pid missing)');
+  }
+
+  await writeSessionLock(freshMission, {
+    session_id: sessionId,
+    runtime,
+    pid,
+    started_at: startedAt,
+    project_path: freshMission.projectPath,
+    milestone_id: selectedMilestone?.id,
+  });
+
+  const updatedMission: Mission = {
+    ...freshMission,
+    status: 'active',
+    sessions: [
+      ...freshMission.sessions,
+      {
+        sessionId,
+        runtime,
+        pid,
+        startedAt,
+        milestoneId: selectedMilestone?.id,
+        lastTaskId: taskId,
+      },
+    ],
+  };
+
+  await saveMission(updatedMission);
+
+  return {
+    missionId: updatedMission.id,
+    taskId,
+    sessionId,
+    runtime,
+    launchCommand,
+    startedAt,
+    pid,
+    lockFile,
+  };
+}
+
+export async function resumeTask(
+  mission: Mission,
+  taskId: string,
+  options: Omit<RunTaskOptions, 'milestoneId'> = {},
+): Promise<TaskRun> {
+  const freshMission = await loadMission(mission.projectPath);
+  const lock = await readSessionLock(freshMission);
+
+  if (lock !== undefined && lock.pid > 0 && isPidAlive(lock.pid)) {
+    throw new Error(
+      `Session ${lock.session_id} is still running (PID ${lock.pid}).`,
+    );
+  }
+
+  let nextMissionState = freshMission;
+
+  if (lock !== undefined) {
+    const endedAt = new Date().toISOString();
+    nextMissionState = markSessionCrashed(freshMission, lock.session_id, endedAt);
+    await saveMission(nextMissionState);
+    await fs.rm(sessionLockPath(nextMissionState), { force: true });
+  }
+
+  return runTask(nextMissionState, taskId, options);
+}
diff --git a/packages/coord/src/status.ts b/packages/coord/src/status.ts
new file mode 100644
index 0000000..c0fb8c9
--- /dev/null
+++ b/packages/coord/src/status.ts
@@ -0,0 +1,183 @@
+import { promises as fs } from 'node:fs';
+import path from 'node:path';
+
+import { loadMission } from './mission.js';
+import { parseTasksFile } from './tasks-file.js';
+import type {
+  Mission,
+  MissionSession,
+  MissionStatusSummary,
+  MissionTask,
+  TaskDetail,
+} from './types.js';
+
+const SESSION_LOCK_FILE = 'session.lock';
+
+interface SessionLockState {
+  session_id?: string;
+  runtime?: string;
+  pid?: number;
+  started_at?: string;
+  milestone_id?: string;
+}
+
+function tasksFilePath(mission: Mission): string {
+  if (path.isAbsolute(mission.tasksFile)) {
+    return mission.tasksFile;
+  }
+
+  return path.join(mission.projectPath, mission.tasksFile);
+}
+
+function sessionLockPath(mission: Mission): string {
+  const orchestratorDir = path.isAbsolute(mission.orchestratorDir)
+    ? mission.orchestratorDir
+    : path.join(mission.projectPath, mission.orchestratorDir);
+
+  return path.join(orchestratorDir, SESSION_LOCK_FILE);
+}
+
+function isPidAlive(pid: number): boolean {
+  try {
+    process.kill(pid, 0);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
+async function readTasks(mission: Mission): Promise<MissionTask[]> {
+  try {
+    const content = await fs.readFile(tasksFilePath(mission), 'utf8');
+    return parseTasksFile(content);
+  } catch (error) {
+    if (
+      typeof error === 'object' &&
+      error !== null &&
+      'code' in error &&
+      (error as { code?: string }).code === 'ENOENT'
+    ) {
+      return [];
+    }
+
+    throw error;
+  }
+}
+
+async function readActiveSession(mission: Mission): Promise<MissionSession | undefined> {
+  let lockRaw: string;
+  try {
+    lockRaw = await fs.readFile(sessionLockPath(mission), 'utf8');
+  } catch (error) {
+    if (
+      typeof error === 'object' &&
+      error !== null &&
+      'code' in error &&
+      (error as { code?: string }).code === 'ENOENT'
+    ) {
+      return undefined;
+    }
+
+    throw error;
+  }
+
+  const lock = JSON.parse(lockRaw) as SessionLockState;
+  if (
+    typeof lock.session_id !== 'string' ||
+    (lock.runtime !== 'claude' && lock.runtime !== 'codex') ||
+    typeof lock.started_at !== 'string'
+  ) {
+    return undefined;
+  }
+
+  const pid = typeof lock.pid === 'number' ? lock.pid : undefined;
+  if (pid !== undefined && pid > 0 && !isPidAlive(pid)) {
+    return undefined;
+  }
+
+  const existingSession = mission.sessions.find(
+    (session) => session.sessionId === lock.session_id,
+  );
+  if (existingSession !== undefined) {
+    return existingSession;
+  }
+
+  return {
+    sessionId: lock.session_id,
+    runtime: lock.runtime,
+    pid,
+    startedAt: lock.started_at,
+    milestoneId: lock.milestone_id,
+  };
+}
+
+export async function getMissionStatus(mission: Mission): Promise<MissionStatusSummary> {
+  const freshMission = await loadMission(mission.projectPath);
+  const tasks = await readTasks(freshMission);
+
+  const done = tasks.filter((task) => task.status === 'done').length;
+  const inProgress = tasks.filter((task) => task.status === 'in-progress').length;
+  const pending = tasks.filter((task) => task.status === 'not-started').length;
+  const blocked = tasks.filter((task) => task.status === 'blocked').length;
+  const cancelled = tasks.filter((task) => task.status === 'cancelled').length;
+  const nextTask = tasks.find((task) => task.status === 'not-started');
+
+  const completedMilestones = freshMission.milestones.filter(
+    (milestone) => milestone.status === 'completed',
+  ).length;
+  const currentMilestone =
+    freshMission.milestones.find((milestone) => milestone.status === 'in-progress')
+    ?? freshMission.milestones.find((milestone) => milestone.status === 'pending');
+
+  const activeSession = await readActiveSession(freshMission);
+
+  return {
+    mission: {
+      id: freshMission.id,
+      name: freshMission.name,
+      status: freshMission.status,
+      projectPath: freshMission.projectPath,
+    },
+    milestones: {
+      total: freshMission.milestones.length,
+      completed: completedMilestones,
+      current: currentMilestone,
+    },
+    tasks: {
+      total: tasks.length,
+      done,
+      inProgress,
+      pending,
+      blocked,
+      cancelled,
+    },
+    nextTaskId: nextTask?.id,
+    activeSession,
+  };
+}
+
+export async function getTaskStatus(
+  mission: Mission,
+  taskId: string,
+): Promise<TaskDetail> {
+  const freshMission = await loadMission(mission.projectPath);
+  const tasks = await readTasks(freshMission);
+
+  const matches = tasks.filter((task) => task.id === taskId);
+  if (matches.length === 0) {
+    throw new Error(`Task not found: ${taskId}`);
+  }
+
+  if (matches.length > 1) {
+    throw new Error(`Duplicate task IDs found: ${taskId}`);
+  }
+
+  const summary = await getMissionStatus(freshMission);
+
+  return {
+    missionId: freshMission.id,
+    task: matches[0],
+    isNextTask: summary.nextTaskId === taskId,
+    activeSession: summary.activeSession,
+  };
+}
diff --git a/packages/coord/src/tasks-file.ts b/packages/coord/src/tasks-file.ts
new file mode 100644
index 0000000..7503849
--- /dev/null
+++ b/packages/coord/src/tasks-file.ts
@@ -0,0 +1,378 @@
+import { promises as fs } from 'node:fs';
+import path from 'node:path';
+
+import type { Mission, MissionTask, TaskStatus } from './types.js';
+import { normalizeTaskStatus } from './types.js';
+
+const TASKS_LOCK_FILE = '.TASKS.md.lock';
+const TASKS_LOCK_STALE_MS = 5 * 60 * 1000;
+const TASKS_LOCK_WAIT_MS = 5 * 1000;
+const TASKS_LOCK_RETRY_MS = 100;
+
+const DEFAULT_TABLE_HEADER = [
+  '| id | status | milestone | description | pr | notes |',
+  '|----|--------|-----------|-------------|----|-------|',
+] as const;
+
+const DEFAULT_TASKS_PREAMBLE = [
+  '# Tasks',
+  '',
+  '> Single-writer: orchestrator only. Workers read but never modify.',
+  '',
+  ...DEFAULT_TABLE_HEADER,
+] as const;
+
+interface ParsedTableRow {
+  readonly lineIndex: number;
+  readonly cells: string[];
+}
+
+interface ParsedTable {
+  readonly headerLineIndex: number;
+  readonly separatorLineIndex: number;
+  readonly headers: string[];
+  readonly rows: ParsedTableRow[];
+  readonly idColumn: number;
+  readonly statusColumn: number;
+}
+
+function normalizeHeaderName(input: string): string {
+  return input.trim().toLowerCase();
+}
+
+function splitMarkdownRow(line: string): string[] {
+  const trimmed = line.trim();
+  if (!trimmed.startsWith('|')) {
+    return [];
+  }
+
+  const parts = trimmed.split(/(?<!\\)\|/);
+  if (parts.length < 3) {
+    return [];
+  }
+
+  return parts.slice(1, -1).map((part) => part.trim().replace(/\\\|/g, '|'));
+}
+
+function isSeparatorRow(cells: readonly string[]): boolean {
+  return (
+    cells.length > 0 &&
+    cells.every((cell) => {
+      const value = cell.trim();
+      return /^:?-{3,}:?$/.test(value);
+    })
+  );
+}
+
+function parseTable(content: string): ParsedTable | undefined {
+  const lines = content.split(/\r?\n/);
+
+  let headerLineIndex = -1;
+  let separatorLineIndex = -1;
+  let headers: string[] = [];
+
+  for (let index = 0; index < lines.length; index += 1) {
+    const cells = splitMarkdownRow(lines[index]);
+    if (cells.length === 0) {
+      continue;
+    }
+
+    const normalized = cells.map(normalizeHeaderName);
+    if (!normalized.includes('id') || !normalized.includes('status')) {
+      continue;
+    }
+
+    if (index + 1 >= lines.length) {
+      continue;
+    }
+
+    const separatorCells = splitMarkdownRow(lines[index + 1]);
+    if (!isSeparatorRow(separatorCells)) {
+      continue;
+    }
+
+    headerLineIndex = index;
+    separatorLineIndex = index + 1;
+    headers = normalized;
+    break;
+  }
+
+  if (headerLineIndex < 0 || separatorLineIndex < 0) {
+    return undefined;
+  }
+
+  const idColumn = headers.indexOf('id');
+  const statusColumn = headers.indexOf('status');
+  if (idColumn < 0 || statusColumn < 0) {
+    return undefined;
+  }
+
+  const rows: ParsedTableRow[] = [];
+  let sawData = false;
+
+  for (let index = separatorLineIndex + 1; index < lines.length; index += 1) {
+    const rawLine = lines[index];
+    const trimmed = rawLine.trim();
+
+    if (!trimmed.startsWith('|')) {
+      if (sawData) {
+        break;
+      }
+      continue;
+    }
+
+    const cells = splitMarkdownRow(rawLine);
+    if (cells.length === 0) {
+      if (sawData) {
+        break;
+      }
+      continue;
+    }
+
+    sawData = true;
+
+    const normalizedRow = [...cells];
+    while (normalizedRow.length < headers.length) {
+      normalizedRow.push('');
+    }
+
+    rows.push({ lineIndex: index, cells: normalizedRow });
+  }
+
+  return {
+    headerLineIndex,
+    separatorLineIndex,
+    headers,
+    rows,
+    idColumn,
+    statusColumn,
+  };
+}
+
+function escapeTableCell(value: string): string {
+  return value.replace(/\|/g, '\\|').replace(/\r?\n/g, ' ').trim();
+}
+
+function formatTableRow(cells: readonly string[]): string {
+  const escaped = cells.map((cell) => escapeTableCell(cell));
+  return `| ${escaped.join(' | ')} |`;
+}
+
+function parseDependencies(raw: string | undefined): string[] {
+  if (raw === undefined || raw.trim().length === 0) {
+    return [];
+  }
+
+  return raw
+    .split(',')
+    .map((value) => value.trim())
+    .filter((value) => value.length > 0);
+}
+
+function resolveTasksFilePath(mission: Mission): string {
+  if (path.isAbsolute(mission.tasksFile)) {
+    return mission.tasksFile;
+  }
+
+  return path.join(mission.projectPath, mission.tasksFile);
+}
+
+function isNodeErrorWithCode(error: unknown, code: string): boolean {
+  return (
+    typeof error === 'object' &&
+    error !== null &&
+    'code' in error &&
+    (error as { code?: string }).code === code
+  );
+}
+
+async function delay(ms: number): Promise<void> {
+  await new Promise((resolve) => {
+    setTimeout(resolve, ms);
+  });
+}
+
+async function acquireLock(lockPath: string): Promise<void> {
+  const startedAt = Date.now();
+
+  while (Date.now() - startedAt < TASKS_LOCK_WAIT_MS) {
+    try {
+      const handle = await fs.open(lockPath, 'wx');
+      await handle.writeFile(
+        JSON.stringify(
+          {
+            pid: process.pid,
+            acquiredAt: new Date().toISOString(),
+          },
+          null,
+          2,
+        ),
+      );
+      await handle.close();
+      return;
+    } catch (error) {
+      if (!isNodeErrorWithCode(error, 'EEXIST')) {
+        throw error;
+      }
+
+      try {
+        const stats = await fs.stat(lockPath);
+        if (Date.now() - stats.mtimeMs > TASKS_LOCK_STALE_MS) {
+          await fs.rm(lockPath, { force: true });
+          continue;
+        }
+      } catch (statError) {
+        if (!isNodeErrorWithCode(statError, 'ENOENT')) {
+          throw statError;
+        }
+      }
+
+      await delay(TASKS_LOCK_RETRY_MS);
+    }
+  }
+
+  throw new Error(`Timed out acquiring TASKS lock: ${lockPath}`);
+}
+
+async function releaseLock(lockPath: string): Promise<void> {
+  await fs.rm(lockPath, { force: true });
+}
+
+async function writeAtomic(filePath: string, content: string): Promise<void> {
+  const directory = path.dirname(filePath);
+  const tempPath = path.join(
+    directory,
+    `.TASKS.md.tmp-${process.pid}-${Date.now()}-${Math.random().toString(16).slice(2)}`,
+  );
+
+  await fs.writeFile(tempPath, content, 'utf8');
+  await fs.rename(tempPath, filePath);
+}
+
+export function parseTasksFile(content: string): MissionTask[] {
+  const parsedTable = parseTable(content);
+  if (parsedTable === undefined) {
+    return [];
+  }
+
+  const headerToColumn = new Map<string, number>();
+  parsedTable.headers.forEach((header, index) => {
+    headerToColumn.set(header, index);
+  });
+
+  const descriptionColumn =
+    headerToColumn.get('description') ?? headerToColumn.get('title') ?? -1;
+  const milestoneColumn = headerToColumn.get('milestone') ?? -1;
+  const prColumn = headerToColumn.get('pr') ?? -1;
+  const notesColumn = headerToColumn.get('notes') ?? -1;
+  const assigneeColumn = headerToColumn.get('assignee') ?? -1;
+  const dependenciesColumn = headerToColumn.get('dependencies') ?? -1;
+
+  const tasks: MissionTask[] = [];
+
+  for (const row of parsedTable.rows) {
+    const id = row.cells[parsedTable.idColumn]?.trim();
+    if (id === undefined || id.length === 0) {
+      continue;
+    }
+
+    const rawStatusValue = row.cells[parsedTable.statusColumn] ?? '';
+    const normalized = normalizeTaskStatus(rawStatusValue);
+
+    const title = descriptionColumn >= 0 ? row.cells[descriptionColumn] ?? '' : '';
+    const milestone = milestoneColumn >= 0 ? row.cells[milestoneColumn] ?? '' : '';
+    const pr = prColumn >= 0 ? row.cells[prColumn] ?? '' : '';
+    const notes = notesColumn >= 0 ? row.cells[notesColumn] ?? '' : '';
+    const assignee = assigneeColumn >= 0 ? row.cells[assigneeColumn] ?? '' : '';
+    const dependenciesRaw =
+      dependenciesColumn >= 0 ? row.cells[dependenciesColumn] ?? '' : '';
+
+    tasks.push({
+      id,
+      title,
+      status: normalized.status,
+      dependencies: parseDependencies(dependenciesRaw),
+      milestone: milestone.length > 0 ? milestone : undefined,
+      pr: pr.length > 0 ? pr : undefined,
+      notes: notes.length > 0 ? notes : undefined,
+      assignee: assignee.length > 0 ? assignee : undefined,
+      rawStatus: normalized.rawStatus,
+      line: row.lineIndex + 1,
+    });
+  }
+
+  return tasks;
+}
+
+export function writeTasksFile(tasks: MissionTask[]): string {
+  const lines: string[] = [...DEFAULT_TASKS_PREAMBLE];
+
+  for (const task of tasks) {
+    lines.push(
+      formatTableRow([
+        task.id,
+        task.status,
+        task.milestone ?? '',
+        task.title,
+        task.pr ?? '',
+        task.notes ?? '',
+      ]),
+    );
+  }
+
+  return `${lines.join('\n')}\n`;
+}
+
+export async function updateTaskStatus(
+  mission: Mission,
+  taskId: string,
+  status: TaskStatus,
+): Promise<void> {
+  const tasksFilePath = resolveTasksFilePath(mission);
+  const lockPath = path.join(path.dirname(tasksFilePath), TASKS_LOCK_FILE);
+
+  await fs.mkdir(path.dirname(tasksFilePath), { recursive: true });
+  await acquireLock(lockPath);
+
+  try {
+    let content: string;
+    try {
+      content = await fs.readFile(tasksFilePath, 'utf8');
+    } catch (error) {
+      if (isNodeErrorWithCode(error, 'ENOENT')) {
+        throw new Error(`TASKS file not found: ${tasksFilePath}`);
+      }
+      throw error;
+    }
+
+    const table = parseTable(content);
+    if (table === undefined) {
+      throw new Error(`Could not parse TASKS table in ${tasksFilePath}`);
+    }
+
+    const matchingRows = table.rows.filter((row) => {
+      const rowTaskId = row.cells[table.idColumn]?.trim();
+      return rowTaskId === taskId;
+    });
+
+    if (matchingRows.length === 0) {
+      throw new Error(`Task not found in TASKS.md: ${taskId}`);
+    }
+
+    if (matchingRows.length > 1) {
+      throw new Error(`Duplicate task IDs found in TASKS.md: ${taskId}`);
+    }
+
+    const targetRow = matchingRows[0];
+    const updatedCells = [...targetRow.cells];
+    updatedCells[table.statusColumn] = status;
+
+    const lines = content.split(/\r?\n/);
+    lines[targetRow.lineIndex] = formatTableRow(updatedCells);
+
+    const updatedContent = `${lines.join('\n').replace(/\n+$/, '')}\n`;
+    await writeAtomic(tasksFilePath, updatedContent);
+  } finally {
+    await releaseLock(lockPath);
+  }
+}
diff --git a/packages/coord/src/types.ts b/packages/coord/src/types.ts
new file mode 100644
index 0000000..f288444
--- /dev/null
+++ b/packages/coord/src/types.ts
@@ -0,0 +1,194 @@
+export type TaskStatus =
+  | 'not-started'
+  | 'in-progress'
+  | 'done'
+  | 'blocked'
+  | 'cancelled';
+
+export type MissionStatus = 'active' | 'paused' | 'completed' | 'inactive';
+
+export type MissionRuntime = 'claude' | 'codex' | 'unknown';
+
+export interface MissionMilestone {
+  id: string;
+  name: string;
+  status: 'pending' | 'in-progress' | 'completed' | 'blocked';
+  branch?: string;
+  issueRef?: string;
+  startedAt?: string;
+  completedAt?: string;
+}
+
+export interface MissionSession {
+  sessionId: string;
+  runtime: MissionRuntime;
+  pid?: number;
+  startedAt: string;
+  endedAt?: string;
+  endedReason?: 'completed' | 'paused' | 'crashed' | 'killed' | 'unknown';
+  milestoneId?: string;
+  lastTaskId?: string;
+  durationSeconds?: number;
+}
+
+export interface Mission {
+  schemaVersion: 1;
+  id: string;
+  name: string;
+  description?: string;
+  projectPath: string;
+  createdAt: string;
+  status: MissionStatus;
+  tasksFile: string;
+  manifestFile: string;
+  scratchpadFile: string;
+  orchestratorDir: string;
+  taskPrefix?: string;
+  qualityGates?: string;
+  milestoneVersion?: string;
+  milestones: MissionMilestone[];
+  sessions: MissionSession[];
+}
+
+export interface MissionTask {
+  id: string;
+  title: string;
+  status: TaskStatus;
+  assignee?: string;
+  dependencies: string[];
+  milestone?: string;
+  pr?: string;
+  notes?: string;
+  rawStatus?: string;
+  line?: number;
+}
+
+export interface TaskRun {
+  missionId: string;
+  taskId: string;
+  sessionId: string;
+  runtime: 'claude' | 'codex';
+  launchCommand: string[];
+  startedAt: string;
+  pid?: number;
+  lockFile: string;
+}
+
+export interface MissionStatusSummary {
+  mission: Pick<Mission, 'id' | 'name' | 'status' | 'projectPath'>;
+  milestones: {
+    total: number;
+    completed: number;
+    current?: MissionMilestone;
+  };
+  tasks: {
+    total: number;
+    done: number;
+    inProgress: number;
+    pending: number;
+    blocked: number;
+    cancelled: number;
+  };
+  nextTaskId?: string;
+  activeSession?: MissionSession;
+}
+
+export interface TaskDetail {
+  missionId: string;
+  task: MissionTask;
+  isNextTask: boolean;
+  activeSession?: MissionSession;
+}
+
+export interface CreateMissionOptions {
+  name: string;
+  projectPath?: string;
+  prefix?: string;
+  milestones?: string[];
+  qualityGates?: string;
+  version?: string;
+  description?: string;
+  force?: boolean;
+}
+
+export interface RunTaskOptions {
+  runtime?: 'claude' | 'codex';
+  mode?: 'interactive' | 'print-only';
+  milestoneId?: string;
+  launchStrategy?: 'subprocess' | 'spawn-adapter';
+  env?: Record<string, string>;
+  command?: string[];
+}
+
+export interface NextTaskCapsule {
+  generatedAt: string;
+  runtime: 'claude' | 'codex';
+  missionId: string;
+  missionName: string;
+  projectPath: string;
+  qualityGates?: string;
+  currentMilestone: {
+    id?: string;
+    name?: string;
+  };
+  nextTask: string;
+  progress: {
+    tasksDone: number;
+    tasksTotal: number;
+    pct: number;
+  };
+  currentBranch?: string;
+}
+
+const LEGACY_TASK_STATUS: Readonly<Record<string, TaskStatus>> = {
+  'not-started': 'not-started',
+  pending: 'not-started',
+  todo: 'not-started',
+  'in-progress': 'in-progress',
+  in_progress: 'in-progress',
+  done: 'done',
+  completed: 'done',
+  blocked: 'blocked',
+  failed: 'blocked',
+  cancelled: 'cancelled',
+};
+
+export function normalizeTaskStatus(input: string): {
+  status: TaskStatus;
+  rawStatus?: string;
+} {
+  const raw = input.trim().toLowerCase();
+  if (raw.length === 0) {
+    return { status: 'not-started' };
+  }
+
+  const normalized = LEGACY_TASK_STATUS[raw];
+  if (normalized === undefined) {
+    return { status: 'not-started', rawStatus: raw };
+  }
+
+  if (raw !== normalized) {
+    return { status: normalized, rawStatus: raw };
+  }
+
+  return { status: normalized };
+}
+
+export function isMissionStatus(value: string): value is MissionStatus {
+  return (
+    value === 'active' ||
+    value === 'paused' ||
+    value === 'completed' ||
+    value === 'inactive'
+  );
+}
+
+export function isTaskStatus(value: string): value is TaskStatus {
+  return (
+    value === 'not-started' ||
+    value === 'in-progress' ||
+    value === 'done' ||
+    value === 'blocked' ||
+    value === 'cancelled'
+  );
+}
diff --git a/packages/coord/tests/mission.test.ts b/packages/coord/tests/mission.test.ts
new file mode 100644
index 0000000..944848e
--- /dev/null
+++ b/packages/coord/tests/mission.test.ts
@@ -0,0 +1,64 @@
+import { promises as fs } from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+
+import { describe, expect, it } from 'vitest';
+
+import { createMission, loadMission, missionFilePath } from '../src/mission.js';
+
+describe('mission lifecycle', () => {
+  it('creates and loads mission state files', async () => {
+    const projectDir = await fs.mkdtemp(path.join(os.tmpdir(), 'coord-mission-'));
+
+    try {
+      const mission = await createMission({
+        name: 'Wave 3 Mission',
+        projectPath: projectDir,
+        milestones: ['Phase One', 'Phase Two'],
+        qualityGates: 'pnpm lint && pnpm typecheck && pnpm test',
+        description: 'Wave 3 implementation',
+      });
+
+      expect(mission.id).toMatch(/^wave-3-mission-\d{8}$/);
+      expect(mission.status).toBe('active');
+      expect(mission.milestones).toHaveLength(2);
+
+      await expect(fs.stat(missionFilePath(projectDir, mission))).resolves.toBeDefined();
+      await expect(fs.stat(path.join(projectDir, 'docs/TASKS.md'))).resolves.toBeDefined();
+      await expect(
+        fs.stat(path.join(projectDir, '.mosaic/orchestrator/mission.json')),
+      ).resolves.toBeDefined();
+
+      const loaded = await loadMission(projectDir);
+      expect(loaded.id).toBe(mission.id);
+      expect(loaded.name).toBe('Wave 3 Mission');
+      expect(loaded.qualityGates).toBe('pnpm lint && pnpm typecheck && pnpm test');
+    } finally {
+      await fs.rm(projectDir, { recursive: true, force: true });
+    }
+  });
+
+  it('rejects inactive missions on load', async () => {
+    const projectDir = await fs.mkdtemp(path.join(os.tmpdir(), 'coord-mission-inactive-'));
+
+    try {
+      const mission = await createMission({
+        name: 'Inactive Mission',
+        projectPath: projectDir,
+      });
+
+      const missionPath = missionFilePath(projectDir, mission);
+      const payload = JSON.parse(await fs.readFile(missionPath, 'utf8')) as {
+        status: string;
+      };
+      payload.status = 'inactive';
+      await fs.writeFile(missionPath, `${JSON.stringify(payload, null, 2)}\n`, 'utf8');
+
+      await expect(loadMission(projectDir)).rejects.toThrow(
+        'Mission exists but is inactive',
+      );
+    } finally {
+      await fs.rm(projectDir, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/packages/coord/tests/tasks-file.test.ts b/packages/coord/tests/tasks-file.test.ts
new file mode 100644
index 0000000..7a95e46
--- /dev/null
+++ b/packages/coord/tests/tasks-file.test.ts
@@ -0,0 +1,74 @@
+import { describe, expect, it } from 'vitest';
+
+import { parseTasksFile, writeTasksFile } from '../src/tasks-file.js';
+import type { MissionTask } from '../src/types.js';
+
+describe('parseTasksFile', () => {
+  it('normalizes legacy statuses from TASKS.md', () => {
+    const content = [
+      '# Tasks — Demo',
+      '',
+      '| id | status | milestone | description | pr | notes |',
+      '|----|--------|-----------|-------------|----|-------|',
+      '| T-1 | pending | phase-1 | First task | #10 | note a |',
+      '| T-2 | completed | phase-1 | Second task | #11 | note b |',
+      '| T-3 | in_progress | phase-2 | Third task |  |  |',
+      '| T-4 | failed | phase-2 | Fourth task |  |  |',
+      '',
+      'trailing text ignored',
+    ].join('\n');
+
+    const tasks = parseTasksFile(content);
+
+    expect(tasks).toHaveLength(4);
+    expect(tasks.map((task) => task.status)).toEqual([
+      'not-started',
+      'done',
+      'in-progress',
+      'blocked',
+    ]);
+    expect(tasks.map((task) => task.rawStatus)).toEqual([
+      'pending',
+      'completed',
+      'in_progress',
+      'failed',
+    ]);
+    expect(tasks[0]?.line).toBe(5);
+  });
+});
+
+describe('writeTasksFile', () => {
+  it('round-trips parse/write output', () => {
+    const tasks: MissionTask[] = [
+      {
+        id: 'W3-001',
+        title: 'Implement parser',
+        status: 'not-started',
+        milestone: 'phase-1',
+        pr: '#20',
+        notes: 'pending',
+        dependencies: [],
+      },
+      {
+        id: 'W3-002',
+        title: 'Implement runner',
+        status: 'in-progress',
+        milestone: 'phase-2',
+        notes: 'active',
+        dependencies: [],
+      },
+    ];
+
+    const content = writeTasksFile(tasks);
+    const reparsed = parseTasksFile(content);
+
+    expect(reparsed).toHaveLength(2);
+    expect(reparsed.map((task) => task.id)).toEqual(['W3-001', 'W3-002']);
+    expect(reparsed.map((task) => task.status)).toEqual([
+      'not-started',
+      'in-progress',
+    ]);
+    expect(reparsed[0]?.title).toBe('Implement parser');
+    expect(reparsed[1]?.milestone).toBe('phase-2');
+  });
+});
diff --git a/packages/coord/tsconfig.json b/packages/coord/tsconfig.json
new file mode 100644
index 0000000..972facb
--- /dev/null
+++ b/packages/coord/tsconfig.json
@@ -0,0 +1,5 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": { "outDir": "dist", "rootDir": "src" },
+  "include": ["src"]
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 70bf70d..f38d515 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -21,6 +21,34 @@ importers:
         specifier: ^5
         version: 5.9.3
 
+  packages/coord:
+    dependencies:
+      '@mosaic/queue':
+        specifier: workspace:*
+        version: link:../queue
+      '@mosaic/types':
+        specifier: workspace:*
+        version: link:../types
+      commander:
+        specifier: ^13
+        version: 13.1.0
+      js-yaml:
+        specifier: ^4
+        version: 4.1.1
+    devDependencies:
+      '@types/js-yaml':
+        specifier: ^4
+        version: 4.0.9
+      '@types/node':
+        specifier: ^22
+        version: 22.19.15
+      typescript:
+        specifier: ^5
+        version: 5.9.3
+      vitest:
+        specifier: ^2
+        version: 2.1.9(@types/node@22.19.15)
+
   packages/mosaic:
     dependencies:
       '@clack/prompts':
@@ -787,6 +815,9 @@ packages:
   '@types/estree@1.0.8':
     resolution: {integrity: sha512-dWHzHa2WqEXI/O1E9OjrocMTKJl2mSrEolh1Iomrv6U+JuNwaHXsXx9bLu5gG7BUWFIN0skIQJQ/L1rIex4X6w==}
 
+  '@types/js-yaml@4.0.9':
+    resolution: {integrity: sha512-k4MGaQl5TGo/iipqb2UDG2UwjXziSWkh0uysQelTlJpX1qGlpUZYm8PnO4DxG1qBomtJUdYJ6qR6xdIah10JLg==}
+
   '@types/node@12.20.55':
     resolution: {integrity: sha512-J8xLz7q2OFulZ2cyGTLE1TbbZcjpno7FaN6zdJNrgAdrJ+DZzh/uFR6YrTb4C+nXakvud8Q4+rbhoIWlYQbUFQ==}
 
@@ -2514,6 +2545,8 @@ snapshots:
 
   '@types/estree@1.0.8': {}
 
+  '@types/js-yaml@4.0.9': {}
+
   '@types/node@12.20.55': {}
 
   '@types/node@22.19.15':