diff --git a/src/cli/commands/doctor/checks/plugin-contracts.ts b/src/cli/commands/doctor/checks/plugin-contracts.ts
new file mode 100644
index 0000000..7304be2
--- /dev/null
+++ b/src/cli/commands/doctor/checks/plugin-contracts.ts
@@ -0,0 +1,155 @@
+/**
+ * S8: Doctor thread - Plugin contract health checks
+ *
+ * Checks:
+ * - Plugin contract registration
+ * - Extension availability for plugin contracts
+ * - Configuration warnings from plugin contract registry
+ */
+
+import type { PluginContractRegistry } from '../../../../domain/plugin-contracts.js'
+
+// ---------------------------------------------------------------------------
+// Types
+// ---------------------------------------------------------------------------
+
+export interface PluginContractCheckResult {
+  name: string
+  status: 'pass' | 'fail' | 'warn'
+  message: string
+  detail?: string
+  remediation?: string
+  mode: 'all' | 'verify' | 'observe' | 'qualify'
+}
+
+export interface PluginContractCheckOptions {
+  pluginContractRegistry?: PluginContractRegistry
+}
+
+// ---------------------------------------------------------------------------
+// Plugin contract presence
+// ---------------------------------------------------------------------------
+
+export function checkPluginContractPresence(options: PluginContractCheckOptions): PluginContractCheckResult {
+  const registry = options.pluginContractRegistry
+
+  if (!registry || registry.getPluginNames().length === 0) {
+    return {
+      name: 'plugin-contracts-presence',
+      status: 'pass',
+      message: 'No plugin contracts configured (optional)',
+      mode: 'all',
+    }
+  }
+
+  const names = registry.getPluginNames()
+  return {
+    name: 'plugin-contracts-presence',
+    status: 'pass',
+    message: `${names.length} plugin contract(s) registered: ${names.join(', ')}`,
+    mode: 'all',
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Plugin contract extension availability
+// ---------------------------------------------------------------------------
+
+export function checkPluginContractExtensions(options: PluginContractCheckOptions): PluginContractCheckResult {
+  const registry = options.pluginContractRegistry
+
+  if (!registry || registry.getPluginNames().length === 0) {
+    return {
+      name: 'plugin-contracts-extensions',
+      status: 'pass',
+      message: 'No plugin contracts to check for extension dependencies',
+      mode: 'all',
+    }
+  }
+
+  const available = new Set(registry.getAvailableExtensions())
+  const missingByPlugin: Record<string, string[]> = {}
+
+  for (const name of registry.getPluginNames()) {
+    const spec = registry.getPluginSpec(name)
+    if (spec?.extensions) {
+      const missing = spec.extensions
+        .filter(e => e.required !== false)
+        .map(e => e.name)
+        .filter(n => !available.has(n))
+      if (missing.length > 0) {
+        missingByPlugin[name] = missing
+      }
+    }
+  }
+
+  if (Object.keys(missingByPlugin).length === 0) {
+    return {
+      name: 'plugin-contracts-extensions',
+      status: 'pass',
+      message: 'All plugin contract extension dependencies are available',
+      mode: 'all',
+    }
+  }
+
+  const details = Object.entries(missingByPlugin)
+    .map(([plugin, exts]) => `  ${plugin}: missing [${exts.join(', ')}]`)
+    .join('\n')
+
+  return {
+    name: 'plugin-contracts-extensions',
+    status: 'warn',
+    message: 'Some plugin contracts have missing extension dependencies',
+    detail: `Missing extensions:\n${details}`,
+    remediation: 'Register the required extensions via app.register(apophisPlugin, { extensions: [...] })',
+    mode: 'all',
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Plugin contract warnings
+// ---------------------------------------------------------------------------
+
+export function checkPluginContractWarnings(options: PluginContractCheckOptions): PluginContractCheckResult {
+  const registry = options.pluginContractRegistry
+
+  if (!registry) {
+    return {
+      name: 'plugin-contracts-warnings',
+      status: 'pass',
+      message: 'No plugin contract registry available',
+      mode: 'all',
+    }
+  }
+
+  const warnings = registry.drainWarnings()
+
+  if (warnings.length === 0) {
+    return {
+      name: 'plugin-contracts-warnings',
+      status: 'pass',
+      message: 'No plugin contract configuration warnings',
+      mode: 'all',
+    }
+  }
+
+  return {
+    name: 'plugin-contracts-warnings',
+    status: 'warn',
+    message: `${warnings.length} plugin contract warning(s)`,
+    detail: warnings.join('\n'),
+    mode: 'all',
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Aggregation
+// ---------------------------------------------------------------------------
+
+export function runPluginContractChecks(options: PluginContractCheckOptions): PluginContractCheckResult[] {
+  return [
+    checkPluginContractPresence(options),
+    checkPluginContractExtensions(options),
+    checkPluginContractWarnings(options),
+  ]
+}
diff --git a/src/cli/commands/doctor/checks/safety.ts b/src/cli/commands/doctor/checks/safety.ts
index b867be4..63b23ad 100644
--- a/src/cli/commands/doctor/checks/safety.ts
+++ b/src/cli/commands/doctor/checks/safety.ts
@@ -226,5 +226,85 @@ export function runSafetyChecks(options: SafetyCheckOptions): SafetyCheckResult[
   results.push(checkEnvironmentPolicies(options));
   results.push(checkProductionSafety(options));
 
+  // Observe readiness: only when filtering for observe (or no filter)
+  if (!modeFilter || modeFilter === 'observe') {
+    results.push(checkObserveReadiness(options));
+  }
+
   return results;
 }
+
+// ---------------------------------------------------------------------------
+// Observe readiness
+// ---------------------------------------------------------------------------
+
+/**
+ * Check that observe mode is properly configured.
+ * Runs when mode filter is 'observe' or unset.
+ */
+export function checkObserveReadiness(options: SafetyCheckOptions): SafetyCheckResult {
+  const { config } = options
+
+  const profileName = config.profile
+  const profile = profileName ? config.profiles?.[profileName] : undefined
+  const presetName = profile?.preset || config.preset
+  const preset = presetName ? config.presets?.[presetName] : undefined
+
+  const hasObserve =
+    preset?.observe === true ||
+    profile?.observe === true
+
+  if (!hasObserve) {
+    return {
+      name: 'observe-readiness',
+      status: 'pass',
+      message: 'Observe not enabled in this preset/profile',
+      mode: 'observe',
+    }
+  }
+
+  const warnings: string[] = []
+
+  // Check sampling rate
+  const sampling = profile?.sampling ?? preset?.sampling
+  if (sampling !== undefined && (sampling < 0 || sampling > 1)) {
+    warnings.push(`Sampling rate ${sampling} is outside valid range [0.0, 1.0]`)
+  }
+
+  // Check sinks
+  const sinks = profile?.sinks ?? preset?.sinks
+  if (!sinks || Object.keys(sinks).length === 0) {
+    warnings.push('No sinks configured — observe will run but events will not be collected')
+  }
+
+  // Check blocking
+  const blocking = profile?.blocking ?? preset?.blocking
+  if (blocking === true) {
+    const env = options.env || detectEnvironment()
+    const isProd = env === 'production' || env === 'prod'
+    if (isProd) {
+      const envPolicy = config.environments?.[env]
+      if (!envPolicy?.allowBlocking) {
+        warnings.push('Blocking observe enabled but allowBlocking is not set in production environment policy')
+      }
+    }
+  }
+
+  if (warnings.length > 0) {
+    return {
+      name: 'observe-readiness',
+      status: 'warn',
+      message: `Observe readiness: ${warnings.length} concern(s)`,
+      detail: warnings.join('\n'),
+      remediation: 'Review observe configuration in presets and profiles',
+      mode: 'observe',
+    }
+  }
+
+  return {
+    name: 'observe-readiness',
+    status: 'pass',
+    message: 'Observe configuration looks ready',
+    mode: 'observe',
+  }
+}
diff --git a/src/cli/commands/doctor/index.ts b/src/cli/commands/doctor/index.ts
index 68d7023..8b0986f 100644
--- a/src/cli/commands/doctor/index.ts
+++ b/src/cli/commands/doctor/index.ts
@@ -23,6 +23,7 @@ import { runConfigChecks } from './checks/config.js';
 import { runRouteChecks } from './checks/routes.js';
 import { runSafetyChecks } from './checks/safety.js';
 import { runDocsChecks } from './checks/docs.js';
+import { runPluginContractChecks } from './checks/plugin-contracts.js';
 
 import { renderJson } from '../../renderers/json.js';
 
@@ -196,6 +197,24 @@ async function runPackageChecks(
     checks.push({ ...result, package: packageName });
   }
 
+  // 6. Plugin contract checks (all modes)
+  try {
+    const { loadApp } = await import('../../core/app-loader.js')
+    const loaded = await loadApp(cwd)
+    const fastify = loaded.fastify
+    if (fastify) {
+      const pcr = (fastify as any)?._apophisPluginContractRegistry
+      if (pcr) {
+        const pcrResults = runPluginContractChecks({ pluginContractRegistry: pcr })
+        for (const result of pcrResults) {
+          checks.push({ ...result, package: packageName })
+        }
+      }
+    }
+  } catch {
+    // App can't be loaded — skip plugin contract checks
+  }
+
   return checks;
 }
 
diff --git a/src/cli/commands/observe/validator.ts b/src/cli/commands/observe/validator.ts
index b449cff..910889c 100644
--- a/src/cli/commands/observe/validator.ts
+++ b/src/cli/commands/observe/validator.ts
@@ -195,9 +195,9 @@ function presetToObserveConfig(preset: PresetDefinition): ObserveProfileConfig {
 function profileToObserveConfig(profile: ProfileDefinition): ObserveProfileConfig {
   return {
     features: profile.features,
-    sampling: (profile as Record<string, unknown>).sampling as number | undefined,
-    blocking: (profile as Record<string, unknown>).blocking as boolean | undefined,
-    sinks: (profile as Record<string, unknown>).sinks as SinkConfig | undefined,
+    sampling: profile.sampling,
+    blocking: profile.blocking,
+    sinks: profile.sinks as SinkConfig | undefined,
   };
 }
 
diff --git a/src/cli/core/config-loader.ts b/src/cli/core/config-loader.ts
index ef7ef62..a1be1b2 100644
--- a/src/cli/core/config-loader.ts
+++ b/src/cli/core/config-loader.ts
@@ -42,11 +42,38 @@ export interface EnvironmentPolicy {
 }
 
 export interface ProfileDefinition {
+  name: string;
+  mode?: 'verify' | 'observe' | 'qualify';
   preset?: string;
   routes?: string[];
   seed?: number;
+  artifactDir?: string;
+  environment?: string;
+  observe?: boolean;
+  sampling?: number;
+  blocking?: boolean;
+  sinks?: Record<string, unknown>;
   features?: string[];
-  [key: string]: unknown;
+  chaos?: boolean;
+  chaosStrategy?: 'one' | 'all' | 'sample' | 'routes';
+  chaosSampleSize?: number;
+  chaosSampleRoutes?: string[];
+}
+
+export interface PresetDefinition {
+  name: string;
+  timeout?: number;
+  parallel?: boolean;
+  chaos?: boolean;
+  observe?: boolean;
+  runs?: number;
+  sampling?: number;
+  blocking?: boolean;
+  sinks?: Record<string, unknown>;
+  features?: string[];
+  chaosStrategy?: 'one' | 'all' | 'sample' | 'routes';
+  chaosSampleSize?: number;
+  chaosSampleRoutes?: string[];
 }
 
 export interface PresetDefinition {
diff --git a/src/cli/core/index.ts b/src/cli/core/index.ts
index 693adcb..9f7a4c5 100644
--- a/src/cli/core/index.ts
+++ b/src/cli/core/index.ts
@@ -73,11 +73,13 @@ function getCommandHelp(command: string): string {
     --routes <filter>   Route filter pattern
     --seed <number>     Deterministic seed
     --changed           Filter to git-modified routes
+    --workspace         Run across all monorepo packages
 
   ${pc.dim('Examples:')}
     apophis verify --profile quick
     apophis verify --routes "POST /users" --seed 42
     apophis verify --changed
+    apophis verify --workspace
 `,
     observe: `
   ${pc.bold('apophis observe')} — Validate runtime observe configuration and reporting setup
@@ -131,11 +133,12 @@ function getCommandHelp(command: string): string {
   ${pc.dim('Options:')}
     --mode <mode>       Focus checks on a mode: verify | observe | qualify
     --strict            Treat warnings as failures
+    --workspace         Run across all monorepo packages
 
   ${pc.dim('Examples:')}
     apophis doctor
-    apophis doctor --mode verify
-    apophis doctor --strict
+    apophis doctor --mode observe
+    apophis doctor --strict --workspace
 `,
     migrate: `
   ${pc.bold('apophis migrate')} — Check and rewrite deprecated config or API usage
diff --git a/src/cli/core/types.ts b/src/cli/core/types.ts
index 2fc76a1..49d685f 100644
--- a/src/cli/core/types.ts
+++ b/src/cli/core/types.ts
@@ -123,6 +123,15 @@ export interface ProfileDefinition {
   seed?: number;
   artifactDir?: string;
   environment?: string;
+  observe?: boolean;
+  sampling?: number;
+  blocking?: boolean;
+  sinks?: Record<string, unknown>;
+  features?: string[];
+  chaos?: boolean;
+  chaosStrategy?: 'one' | 'all' | 'sample' | 'routes';
+  chaosSampleSize?: number;
+  chaosSampleRoutes?: string[];
 }
 
 /**