diff --git a/workspace-server/internal/handlers/instructions.go b/workspace-server/internal/handlers/instructions.go
new file mode 100644
index 00000000..41dcd8e3
--- /dev/null
+++ b/workspace-server/internal/handlers/instructions.go
@@ -0,0 +1,271 @@
+package handlers
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/Molecule-AI/molecule-monorepo/platform/internal/db"
+	"github.com/gin-gonic/gin"
+)
+
+type InstructionsHandler struct{}
+
+func NewInstructionsHandler() *InstructionsHandler {
+	return &InstructionsHandler{}
+}
+
+type Instruction struct {
+	ID          string    `json:"id"`
+	Scope       string    `json:"scope"`
+	ScopeTarget *string   `json:"scope_target"`
+	Title       string    `json:"title"`
+	Content     string    `json:"content"`
+	Priority    int       `json:"priority"`
+	Enabled     bool      `json:"enabled"`
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+}
+
+// List returns instructions filtered by scope. Agents call this at startup
+// to fetch their full instruction set (global + team + workspace).
+//
+// GET /instructions?scope=global
+// GET /instructions?workspace_id=<uuid>  (returns global + team + workspace)
+func (h *InstructionsHandler) List(c *gin.Context) {
+	ctx := c.Request.Context()
+	scope := c.Query("scope")
+	workspaceID := c.Query("workspace_id")
+
+	var rows_ interface{ Close() error }
+	var err error
+
+	if workspaceID != "" {
+		// Agent bootstrap: fetch all applicable instructions (global + team + workspace)
+		// ordered by scope priority (global first) then user priority descending.
+		var teamSlug *string
+		db.DB.QueryRowContext(ctx,
+			`SELECT t.slug FROM teams t
+			 JOIN team_members tm ON tm.team_id = t.id
+			 WHERE tm.workspace_id = $1 LIMIT 1`, workspaceID).Scan(&teamSlug)
+
+		query := `SELECT id, scope, scope_target, title, content, priority, enabled, created_at, updated_at
+			FROM platform_instructions
+			WHERE enabled = true AND (
+				scope = 'global'
+				OR (scope = 'team' AND scope_target = $1)
+				OR (scope = 'workspace' AND scope_target = $2)
+			)
+			ORDER BY CASE scope WHEN 'global' THEN 0 WHEN 'team' THEN 1 WHEN 'workspace' THEN 2 END,
+			         priority DESC`
+
+		teamTarget := ""
+		if teamSlug != nil {
+			teamTarget = *teamSlug
+		}
+		r, qErr := db.DB.QueryContext(ctx, query, teamTarget, workspaceID)
+		if qErr != nil {
+			log.Printf("Instructions list error: %v", qErr)
+			c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+			return
+		}
+		rows_ = r
+		defer r.Close()
+		instructions := scanInstructions(r)
+		c.JSON(http.StatusOK, instructions)
+		return
+	}
+
+	// Admin listing by scope
+	query := `SELECT id, scope, scope_target, title, content, priority, enabled, created_at, updated_at
+		FROM platform_instructions WHERE 1=1`
+	args := []interface{}{}
+	if scope != "" {
+		query += ` AND scope = $1`
+		args = append(args, scope)
+	}
+	query += ` ORDER BY scope, priority DESC, created_at`
+
+	r, qErr := db.DB.QueryContext(ctx, query, args...)
+	if qErr != nil {
+		log.Printf("Instructions list error: %v", qErr)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	rows_ = r
+	_ = rows_
+	defer r.Close()
+	c.JSON(http.StatusOK, scanInstructions(r))
+}
+
+// Create adds a new platform instruction.
+// POST /instructions
+func (h *InstructionsHandler) Create(c *gin.Context) {
+	var body struct {
+		Scope       string  `json:"scope" binding:"required"`
+		ScopeTarget *string `json:"scope_target"`
+		Title       string  `json:"title" binding:"required"`
+		Content     string  `json:"content" binding:"required"`
+		Priority    int     `json:"priority"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "scope, title, and content are required"})
+		return
+	}
+	if body.Scope != "global" && body.Scope != "team" && body.Scope != "workspace" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "scope must be global, team, or workspace"})
+		return
+	}
+	if body.Scope != "global" && (body.ScopeTarget == nil || *body.ScopeTarget == "") {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "scope_target required for team/workspace scope"})
+		return
+	}
+
+	var id string
+	err := db.DB.QueryRowContext(c.Request.Context(),
+		`INSERT INTO platform_instructions (scope, scope_target, title, content, priority)
+		 VALUES ($1, $2, $3, $4, $5) RETURNING id`,
+		body.Scope, body.ScopeTarget, body.Title, body.Content, body.Priority,
+	).Scan(&id)
+	if err != nil {
+		log.Printf("Instructions create error: %v", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "insert failed"})
+		return
+	}
+	c.JSON(http.StatusCreated, gin.H{"id": id})
+}
+
+// Update modifies an existing instruction.
+// PUT /instructions/:id
+func (h *InstructionsHandler) Update(c *gin.Context) {
+	id := c.Param("id")
+	var body struct {
+		Title    *string `json:"title"`
+		Content  *string `json:"content"`
+		Priority *int    `json:"priority"`
+		Enabled  *bool   `json:"enabled"`
+	}
+	if err := c.ShouldBindJSON(&body); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request"})
+		return
+	}
+
+	result, err := db.DB.ExecContext(c.Request.Context(),
+		`UPDATE platform_instructions SET
+			title = COALESCE($2, title),
+			content = COALESCE($3, content),
+			priority = COALESCE($4, priority),
+			enabled = COALESCE($5, enabled),
+			updated_at = NOW()
+		 WHERE id = $1`,
+		id, body.Title, body.Content, body.Priority, body.Enabled,
+	)
+	if err != nil {
+		log.Printf("Instructions update error: %v", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "update failed"})
+		return
+	}
+	if n, _ := result.RowsAffected(); n == 0 {
+		c.JSON(http.StatusNotFound, gin.H{"error": "instruction not found"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"status": "updated"})
+}
+
+// Delete removes an instruction.
+// DELETE /instructions/:id
+func (h *InstructionsHandler) Delete(c *gin.Context) {
+	id := c.Param("id")
+	result, err := db.DB.ExecContext(c.Request.Context(),
+		`DELETE FROM platform_instructions WHERE id = $1`, id)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "delete failed"})
+		return
+	}
+	if n, _ := result.RowsAffected(); n == 0 {
+		c.JSON(http.StatusNotFound, gin.H{"error": "instruction not found"})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"status": "deleted"})
+}
+
+// Resolve returns the merged instruction text for a workspace — all enabled
+// instructions across global → team → workspace scope, concatenated in order.
+// This is what the Python runtime calls to get the full instruction set.
+//
+// GET /instructions/resolve?workspace_id=<uuid>
+func (h *InstructionsHandler) Resolve(c *gin.Context) {
+	workspaceID := c.Query("workspace_id")
+	if workspaceID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "workspace_id required"})
+		return
+	}
+	ctx := c.Request.Context()
+
+	var teamSlug string
+	db.DB.QueryRowContext(ctx,
+		`SELECT COALESCE(t.slug, '') FROM teams t
+		 JOIN team_members tm ON tm.team_id = t.id
+		 WHERE tm.workspace_id = $1 LIMIT 1`, workspaceID).Scan(&teamSlug)
+
+	rows, err := db.DB.QueryContext(ctx,
+		`SELECT scope, title, content FROM platform_instructions
+		 WHERE enabled = true AND (
+			scope = 'global'
+			OR (scope = 'team' AND scope_target = $1)
+			OR (scope = 'workspace' AND scope_target = $2)
+		 )
+		 ORDER BY CASE scope WHEN 'global' THEN 0 WHEN 'team' THEN 1 WHEN 'workspace' THEN 2 END,
+		          priority DESC`,
+		teamSlug, workspaceID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "query failed"})
+		return
+	}
+	defer rows.Close()
+
+	var merged string
+	currentScope := ""
+	for rows.Next() {
+		var scope, title, content string
+		if err := rows.Scan(&scope, &title, &content); err != nil {
+			continue
+		}
+		if scope != currentScope {
+			scopeLabel := map[string]string{
+				"global":    "Platform-Wide Rules",
+				"team":      "Team Rules",
+				"workspace": "Role-Specific Rules",
+			}[scope]
+			merged += "\n## " + scopeLabel + "\n\n"
+			currentScope = scope
+		}
+		merged += "### " + title + "\n" + content + "\n\n"
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"workspace_id": workspaceID,
+		"team_slug":    teamSlug,
+		"instructions": merged,
+	})
+}
+
+func scanInstructions(rows interface {
+	Next() bool
+	Scan(dest ...interface{}) error
+}) []Instruction {
+	var instructions []Instruction
+	for rows.Next() {
+		var inst Instruction
+		if err := rows.Scan(&inst.ID, &inst.Scope, &inst.ScopeTarget, &inst.Title,
+			&inst.Content, &inst.Priority, &inst.Enabled, &inst.CreatedAt, &inst.UpdatedAt); err != nil {
+			log.Printf("Instructions scan error: %v", err)
+			continue
+		}
+		instructions = append(instructions, inst)
+	}
+	if instructions == nil {
+		instructions = []Instruction{}
+	}
+	return instructions
+}
diff --git a/workspace-server/internal/router/router.go b/workspace-server/internal/router/router.go
index b9610fd6..674231ed 100644
--- a/workspace-server/internal/router/router.go
+++ b/workspace-server/internal/router/router.go
@@ -364,6 +364,19 @@ func Setup(hub *ws.Hub, broadcaster *events.Broadcaster, prov *provisioner.Provi
 		adminAuth.DELETE("/admin/secrets/:key", sechGlobal.DeleteGlobal)
 	}
 
+	// Platform instructions — configurable rules with global/team/workspace scope.
+	// Admin endpoints for CRUD; workspace-facing resolve endpoint for agent bootstrap.
+	{
+		instrH := handlers.NewInstructionsHandler()
+		adminInstr := r.Group("", middleware.AdminAuth(db.DB))
+		adminInstr.GET("/instructions", instrH.List)
+		adminInstr.POST("/instructions", instrH.Create)
+		adminInstr.PUT("/instructions/:id", instrH.Update)
+		adminInstr.DELETE("/instructions/:id", instrH.Delete)
+		// Resolve endpoint is open to workspace auth (agents call it at startup)
+		r.GET("/instructions/resolve", instrH.Resolve)
+	}
+
 	// Admin — cross-workspace schedule health monitoring (issue #618).
 	// Lets cron-audit agents and operators detect silent schedule failures
 	// across all workspaces without holding individual workspace bearer tokens.
diff --git a/workspace-server/migrations/040_platform_instructions.down.sql b/workspace-server/migrations/040_platform_instructions.down.sql
new file mode 100644
index 00000000..acebc56f
--- /dev/null
+++ b/workspace-server/migrations/040_platform_instructions.down.sql
@@ -0,0 +1,2 @@
+DROP INDEX IF EXISTS idx_platform_instructions_scope;
+DROP TABLE IF EXISTS platform_instructions;
diff --git a/workspace-server/migrations/040_platform_instructions.up.sql b/workspace-server/migrations/040_platform_instructions.up.sql
new file mode 100644
index 00000000..ebf812fe
--- /dev/null
+++ b/workspace-server/migrations/040_platform_instructions.up.sql
@@ -0,0 +1,18 @@
+-- Platform-level configurable instructions with global/team/workspace scope.
+-- Injected into every agent's system prompt at startup and refreshed
+-- periodically, so platform operators can enforce rules without editing
+-- template files.
+CREATE TABLE IF NOT EXISTS platform_instructions (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    scope       TEXT NOT NULL CHECK (scope IN ('global', 'team', 'workspace')),
+    scope_target TEXT,  -- NULL for global, team slug for team, workspace_id for workspace
+    title       TEXT NOT NULL,
+    content     TEXT NOT NULL,
+    priority    INT DEFAULT 0,  -- higher = shown first within scope
+    enabled     BOOLEAN DEFAULT true,
+    created_at  TIMESTAMPTZ DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ DEFAULT NOW()
+);
+
+CREATE INDEX IF NOT EXISTS idx_platform_instructions_scope
+    ON platform_instructions (scope, scope_target) WHERE enabled = true;
diff --git a/workspace/adapter_base.py b/workspace/adapter_base.py
index 0de914c4..8cb5cb8d 100644
--- a/workspace/adapter_base.py
+++ b/workspace/adapter_base.py
@@ -294,7 +294,7 @@ class BaseAdapter(ABC):
         from plugins import load_plugins
         from skill_loader.loader import load_skills
         from coordinator import get_children, get_parent_context, build_children_description
-        from prompt import build_system_prompt, get_peer_capabilities
+        from prompt import build_system_prompt, get_peer_capabilities, get_platform_instructions
         from builtin_tools.approval import request_approval
         from builtin_tools.delegation import delegate_to_workspace, check_delegation_status
         from builtin_tools.memory import commit_memory, search_memory
@@ -344,6 +344,7 @@ class BaseAdapter(ABC):
 
         # Build system prompt with all context
         peers = await get_peer_capabilities(platform_url, config.workspace_id)
+        platform_instructions = await get_platform_instructions(platform_url, config.workspace_id)
         coordinator_prompt = build_children_description(children) if is_coordinator else ""
         extra_prompts = list(plugins.prompt_fragments)
         if coordinator_prompt:
@@ -355,6 +356,7 @@ class BaseAdapter(ABC):
             plugin_rules=plugins.rules,
             plugin_prompts=extra_prompts,
             parent_context=parent_context,
+            platform_instructions=platform_instructions,
         )
 
         return SetupResult(
diff --git a/workspace/prompt.py b/workspace/prompt.py
index 33de1265..818ec182 100644
--- a/workspace/prompt.py
+++ b/workspace/prompt.py
@@ -1,5 +1,6 @@
 """Build the system prompt for the workspace agent."""
 
+import os
 from pathlib import Path
 
 from skill_loader.loader import LoadedSkill
@@ -25,6 +26,24 @@ async def get_peer_capabilities(platform_url: str, workspace_id: str) -> list[di
     return []
 
 
+async def get_platform_instructions(platform_url: str, workspace_id: str) -> str:
+    """Fetch resolved platform instructions (global + team + workspace scope)."""
+    try:
+        import httpx
+
+        async with httpx.AsyncClient(timeout=10.0) as client:
+            resp = await client.get(
+                f"{platform_url}/instructions/resolve",
+                params={"workspace_id": workspace_id},
+            )
+            if resp.status_code == 200:
+                data = resp.json()
+                return data.get("instructions", "")
+    except Exception as e:
+        print(f"Warning: could not fetch platform instructions: {e}")
+    return ""
+
+
 def build_system_prompt(
     config_path: str,
     workspace_id: str,
@@ -34,6 +53,7 @@ def build_system_prompt(
     plugin_rules: list[str] | None = None,
     plugin_prompts: list[str] | None = None,
     parent_context: list[dict] | None = None,
+    platform_instructions: str = "",
 ) -> str:
     """Build the complete system prompt.
 
@@ -50,6 +70,12 @@ def build_system_prompt(
     """
     parts = []
 
+    # Platform instructions (global → team → workspace scope) go first so
+    # they take highest precedence in the context window.
+    if platform_instructions:
+        parts.append("# Platform Instructions\n")
+        parts.append(platform_instructions)
+
     # Load prompt files in order
     files_to_load = list(prompt_files or [])
     if not files_to_load: