diff --git a/src/pages/ProposalDetailPage.tsx b/src/pages/ProposalDetailPage.tsx
index bc3c3d2..0e43f69 100644
--- a/src/pages/ProposalDetailPage.tsx
+++ b/src/pages/ProposalDetailPage.tsx
@@ -1,7 +1,7 @@
 import { useState, useEffect } from 'react'
 import { useParams, useNavigate, useSearchParams } from 'react-router-dom'
 import api from '@/services/api'
-import type { Proposal, Milestone } from '@/types'
+import type { Proposal, Milestone, Essential, EssentialType } from '@/types'
 import dayjs from 'dayjs'
 import CopyableCode from '@/components/CopyableCode'
 
@@ -24,6 +24,18 @@ export default function ProposalDetailPage() {
   const [editDescription, setEditDescription] = useState('')
   const [editLoading, setEditLoading] = useState(false)
 
+  // Essential state
+  const [essentials, setEssentials] = useState<Essential[]>([])
+  const [loadingEssentials, setLoadingEssentials] = useState(false)
+
+  // Essential create/edit state
+  const [showEssentialModal, setShowEssentialModal] = useState(false)
+  const [editingEssential, setEditingEssential] = useState<Essential | null>(null)
+  const [essentialTitle, setEssentialTitle] = useState('')
+  const [essentialType, setEssentialType] = useState<EssentialType>('feature')
+  const [essentialDesc, setEssentialDesc] = useState('')
+  const [essentialLoading, setEssentialLoading] = useState(false)
+
   const fetchProposal = () => {
     if (!projectId) return
     api.get<Proposal>(`/projects/${projectId}/proposals/${id}`).then(({ data }) => setProposal(data))
@@ -39,6 +51,18 @@ export default function ProposalDetailPage() {
       .then(({ data }) => setMilestones(data.filter((m) => m.status === 'open')))
   }
 
+  const fetchEssentials = () => {
+    if (!projectId || !id) return
+    setLoadingEssentials(true)
+    api.get<Essential[]>(`/projects/${projectId}/proposals/${id}/essentials`)
+      .then(({ data }) => setEssentials(data))
+      .finally(() => setLoadingEssentials(false))
+  }
+
+  useEffect(() => {
+    fetchEssentials()
+  }, [id, projectId])
+
   const handleAccept = async () => {
     if (!selectedMilestone || !projectId) return
     setActionLoading(true)
@@ -109,6 +133,64 @@ export default function ProposalDetailPage() {
     }
   }
 
+  // Essential handlers
+  const openEssentialModal = (essential?: Essential) => {
+    if (essential) {
+      setEditingEssential(essential)
+      setEssentialTitle(essential.title)
+      setEssentialType(essential.type)
+      setEssentialDesc(essential.description || '')
+    } else {
+      setEditingEssential(null)
+      setEssentialTitle('')
+      setEssentialType('feature')
+      setEssentialDesc('')
+    }
+    setError('')
+    setShowEssentialModal(true)
+  }
+
+  const handleSaveEssential = async () => {
+    if (!projectId || !id) return
+    setEssentialLoading(true)
+    setError('')
+    try {
+      if (editingEssential) {
+        await api.patch(`/projects/${projectId}/proposals/${id}/essentials/${editingEssential.id}`, {
+          title: essentialTitle,
+          type: essentialType,
+          description: essentialDesc || null,
+        })
+      } else {
+        await api.post(`/projects/${projectId}/proposals/${id}/essentials`, {
+          title: essentialTitle,
+          type: essentialType,
+          description: essentialDesc || null,
+        })
+      }
+      setShowEssentialModal(false)
+      fetchEssentials()
+    } catch (err: any) {
+      setError(err.response?.data?.detail || 'Save failed')
+    } finally {
+      setEssentialLoading(false)
+    }
+  }
+
+  const handleDeleteEssential = async (essentialId: number) => {
+    if (!projectId || !id) return
+    if (!confirm('Are you sure you want to delete this Essential?')) return
+    setEssentialLoading(true)
+    try {
+      await api.delete(`/projects/${projectId}/proposals/${id}/essentials/${essentialId}`)
+      fetchEssentials()
+    } catch (err: any) {
+      setError(err.response?.data?.detail || 'Delete failed')
+    } finally {
+      setEssentialLoading(false)
+    }
+  }
+
   if (!proposal) return <div className="loading">Loading...</div>
 
   const statusBadgeClass = (s: string) => {
@@ -150,6 +232,56 @@ export default function ProposalDetailPage() {
         <p style={{ whiteSpace: 'pre-wrap' }}>{proposal.description || 'No description'}</p>
       </div>
 
+      {/* Essentials section */}
+      <div className="section">
+        <div style={{ display: 'flex', justifyContent: 'space-between', alignItems: 'center', marginBottom: 12 }}>
+          <h3>Essentials ({essentials.length})</h3>
+          {proposal.status === 'open' && (
+            <button className="btn-primary" onClick={() => openEssentialModal()}>+ New Essential</button>
+          )}
+        </div>
+        {loadingEssentials ? (
+          <div className="loading">Loading...</div>
+        ) : essentials.length === 0 ? (
+          <div className="empty" style={{ padding: '20px 0', color: 'var(--text-secondary)' }}>
+            No essentials yet. {proposal.status === 'open' ? 'Add one to define deliverables for this proposal.' : ''}
+          </div>
+        ) : (
+          <div className="milestone-grid">
+            {essentials.map((e) => (
+              <div key={e.id} className="milestone-card">
+                <div className="milestone-card-header" style={{ display: 'flex', alignItems: 'center', gap: 8, flexWrap: 'wrap' }}>
+                  <span className="badge">{e.type}</span>
+                  {e.essential_code && <span className="badge"><CopyableCode code={e.essential_code} /></span>}
+                  <h4 style={{ margin: 0, flex: 1 }}>{e.title}</h4>
+                  {proposal.status === 'open' && (
+                    <div style={{ display: 'flex', gap: 4 }}>
+                      <button
+                        className="btn-transition"
+                        style={{ padding: '4px 8px', fontSize: '0.8rem' }}
+                        onClick={() => openEssentialModal(e)}
+                      >
+                        Edit
+                      </button>
+                      <button
+                        className="btn-danger"
+                        style={{ padding: '4px 8px', fontSize: '0.8rem' }}
+                        onClick={() => handleDeleteEssential(e.id)}
+                      >
+                        Delete
+                      </button>
+                    </div>
+                  )}
+                </div>
+                {e.description && (
+                  <p style={{ marginTop: 8, color: 'var(--text-secondary)', whiteSpace: 'pre-wrap' }}>{e.description}</p>
+                )}
+              </div>
+            ))}
+          </div>
+        )}
+      </div>
+
       {/* Generated tasks (shown when accepted) */}
       {proposal.status === 'accepted' && proposal.generated_tasks && proposal.generated_tasks.length > 0 && (
         <div className="section">
@@ -278,6 +410,56 @@ export default function ProposalDetailPage() {
           </div>
         </div>
       )}
+      {/* Essential create/edit modal */}
+      {showEssentialModal && (
+        <div className="modal-overlay" onClick={() => setShowEssentialModal(false)}>
+          <div className="modal" onClick={(e) => e.stopPropagation()}>
+            <h3>{editingEssential ? 'Edit Essential' : 'New Essential'}</h3>
+            <label style={{ display: 'block', marginBottom: 8 }}>
+              <strong>Title</strong>
+              <input
+                type="text"
+                value={essentialTitle}
+                onChange={(e) => setEssentialTitle(e.target.value)}
+                style={{ width: '100%', marginTop: 4 }}
+                placeholder="Essential title"
+              />
+            </label>
+            <label style={{ display: 'block', marginBottom: 8 }}>
+              <strong>Type</strong>
+              <select
+                value={essentialType}
+                onChange={(e) => setEssentialType(e.target.value as EssentialType)}
+                style={{ width: '100%', marginTop: 4 }}
+              >
+                <option value="feature">Feature</option>
+                <option value="improvement">Improvement</option>
+                <option value="refactor">Refactor</option>
+              </select>
+            </label>
+            <label style={{ display: 'block', marginBottom: 8 }}>
+              <strong>Description</strong>
+              <textarea
+                value={essentialDesc}
+                onChange={(e) => setEssentialDesc(e.target.value)}
+                rows={4}
+                style={{ width: '100%', marginTop: 4 }}
+                placeholder="Description (optional)"
+              />
+            </label>
+            <div style={{ marginTop: 12, display: 'flex', gap: 8 }}>
+              <button
+                className="btn-primary"
+                onClick={handleSaveEssential}
+                disabled={!essentialTitle.trim() || essentialLoading}
+              >
+                {essentialLoading ? 'Saving...' : 'Save'}
+              </button>
+              <button className="btn-back" onClick={() => setShowEssentialModal(false)}>Cancel</button>
+            </div>
+          </div>
+        </div>
+      )}
     </div>
   )
 }
diff --git a/src/types/index.ts b/src/types/index.ts
index 0e5590b..a0fb7b5 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -137,6 +137,7 @@ export interface Proposal {
   created_by_id: number | null
   created_by_username: string | null
   feat_task_id: string | null
+  essentials: Essential[] | null
   generated_tasks: GeneratedTask[] | null
   created_at: string
   updated_at: string | null
@@ -153,6 +154,20 @@ export interface GeneratedTask {
   task_subtype: string | null
 }
 
+export type EssentialType = 'feature' | 'improvement' | 'refactor'
+
+export interface Essential {
+  id: number
+  essential_code: string
+  proposal_id: number
+  type: EssentialType
+  title: string
+  description: string | null
+  created_by_id: number | null
+  created_at: string
+  updated_at: string | null
+}
+
 export interface LoginResponse {
   access_token: string
   token_type: string