diff --git a/backend/apps/agents/agents.py b/backend/apps/agents/agents.py
index 50fd6773..9b6f3f45 100644
--- a/backend/apps/agents/agents.py
+++ b/backend/apps/agents/agents.py
@@ -34,6 +34,7 @@ from backend.apps.agents.session_store import (
     load,
 )
 from backend.apps.agents import ws
+from backend.apps.agents.compose_system_prompt import compose_system_prompt
 from claude_agent_sdk import ClaudeAgentOptions
 
 SESSIONS: dict[str, Agent] = {}
@@ -51,7 +52,7 @@ async def p_send_browser_command(
     action: str, browser_id: str, tab_id: str, params: dict,
 ) -> dict:
     """BrowserCommandFn implementation that routes through the browser FutureBridge."""
-    request_id = uuid4().hex
+    request_id: str = uuid4().hex
     if not ws.has_global_connections():
         return {"error": "No dashboard connected. Open the dashboard to use browser tools."}
     return await ws.BROWSER_BRIDGE.request(
@@ -133,20 +134,22 @@ class LaunchBody(BaseModel):
 
 @agents.router.post("/launch")
 async def launch(body: LaunchBody) -> dict:
-    # TODO: build ClaudeAgentOptions from body once prompt/options builder exists
+    system_prompt = compose_system_prompt(
+        session_prompt=body.system_prompt or None,
+    )
     agent: Agent = Agent(
         model=body.model,
         mode=body.mode,
-        status="running",
+        status="stopped",
         config=ClaudeAgentOptions(
-            system_prompt=body.system_prompt,
+            system_prompt=system_prompt,
             max_turns=body.max_turns,
         ),
     )
     agent.on_event = p_make_session_emitter(agent.session_id)
     SESSIONS[agent.session_id] = agent
-    await agent._emit(AgentStatusEvent(
-        session_id=agent.session_id, status="running",
+    await agent.emit(AgentStatusEvent(
+        session_id=agent.session_id, status="stopped",
         session=agent.snapshot(),
     ))
     return {"session_id": agent.session_id, "session": agent.snapshot().model_dump(mode="json")}
@@ -163,7 +166,7 @@ async def update_session(session_id: str, body: UpdateBody) -> dict:
         agent.name = body.name
     if body.system_prompt is not None:
         agent.config.system_prompt = body.system_prompt
-    await agent._emit(AgentStatusEvent(
+    await agent.emit(AgentStatusEvent(
         session_id=session_id, status=agent.status,
         session=agent.snapshot(),
     ))
@@ -254,7 +257,7 @@ async def edit_message(session_id: str, body: EditMessageBody) -> dict:
     fork: Agent = agent.branch(body.message_id)
     SESSIONS[fork.session_id] = fork
 
-    edited_msg = UserMessage(content=body.content, branch_id=fork.branch_id)
+    edited_msg: UserMessage = UserMessage(content=body.content, branch_id=fork.branch_id)
     await fork.send_message(edited_msg)
     return {"ok": True, "branch_id": fork.branch_id, "session_id": fork.session_id}
 
diff --git a/backend/apps/agents/compose_system_prompt.py b/backend/apps/agents/compose_system_prompt.py
new file mode 100644
index 00000000..32548bf3
--- /dev/null
+++ b/backend/apps/agents/compose_system_prompt.py
@@ -0,0 +1,30 @@
+"""Pure prompt-building helpers.
+
+All functions are stateless — they accept data as parameters and return
+strings.  No imports from ``apps/`` or any external stores.
+"""
+
+from typing import Optional, List
+from typeguard import typechecked
+
+@typechecked
+def compose_system_prompt(
+    global_default: Optional[str] = None,
+    mode_prompt: Optional[str] = None,
+    session_prompt: Optional[str] = None,
+    connected_tools_ctx: Optional[str] = None,
+    browser_ctx: Optional[str] = None,
+) -> Optional[str]:
+    """Layer multiple prompt sources into one system prompt.
+
+    Order matters — earlier layers provide base context, later layers
+    override or augment.
+    """
+    parts: List[str] = [p for p in (
+        global_default,
+        mode_prompt,
+        session_prompt,
+        connected_tools_ctx,
+        browser_ctx,
+    ) if p]
+    return "\n\n".join(parts) if parts else None
\ No newline at end of file
diff --git a/backend/core/shared_structs/agent/Message/Message.py b/backend/core/shared_structs/agent/Message/Message.py
index 28b8fed1..d75e9cd1 100644
--- a/backend/core/shared_structs/agent/Message/Message.py
+++ b/backend/core/shared_structs/agent/Message/Message.py
@@ -12,6 +12,9 @@ from backend.core.shared_structs.agent.Message.agent_inputs import (
 from backend.core.shared_structs.agent.Message.agent_outputs import (
     ToolCallContent, ToolResultContent
 )
+from backend.core.shared_structs.agent.Message.prompt_utils import (
+    resolve_context_paths, resolve_forced_tools, resolve_attached_skills,
+)
 
 class Message(BaseModel):
     id: str = Field(default_factory=lambda: uuid4().hex)
@@ -39,7 +42,15 @@ class UserMessage(Message):
 
     @typechecked
     def to_prompt(self) -> PromptMsgDict:
-        blocks: List[PromptBlock] = [TextPromptBlock(type="text", text=self.content)]
+        parts: List[str] = [
+            resolve_forced_tools(self.forced_tools),
+            resolve_context_paths(self.context_paths),
+            resolve_attached_skills(self.attached_skills),
+            self.content,
+        ]
+        full_text: str = "\n\n".join(p for p in parts if p)
+
+        blocks: List[PromptBlock] = [TextPromptBlock(type="text", text=full_text)]
         for data, media_type in zip[tuple[str, str]](self.images, self.image_media_types):
             blocks.append(ImagePromptBlock(
                 type="image",
diff --git a/backend/core/shared_structs/agent/Message/agent_inputs.py b/backend/core/shared_structs/agent/Message/agent_inputs.py
index 5ffb22d2..b74c6f8b 100644
--- a/backend/core/shared_structs/agent/Message/agent_inputs.py
+++ b/backend/core/shared_structs/agent/Message/agent_inputs.py
@@ -30,4 +30,5 @@ class ContextPath(BaseModel):
 
 class SkillMeta(BaseModel):
     id: str
-    name: str
\ No newline at end of file
+    name: str
+    content: str = ""
\ No newline at end of file
diff --git a/backend/core/shared_structs/agent/Message/prompt_utils.py b/backend/core/shared_structs/agent/Message/prompt_utils.py
new file mode 100644
index 00000000..d964806d
--- /dev/null
+++ b/backend/core/shared_structs/agent/Message/prompt_utils.py
@@ -0,0 +1,101 @@
+"""Pure prompt-building helpers.
+
+All functions are stateless — they accept data as parameters and return
+strings.  No imports from ``apps/`` or any external stores.
+"""
+
+import os
+from typing import List
+
+from backend.core.shared_structs.agent.Message.agent_inputs import ContextPath, SkillMeta
+from typeguard import typechecked
+
+MAX_FILE_READ_BYTES = 512_000
+DIR_TREE_MAX_DEPTH = 4
+
+@typechecked
+def p_build_dir_tree(
+    root: str,
+    max_depth: int = DIR_TREE_MAX_DEPTH,
+    prefix: str = "",
+) -> List[str]:
+    lines: List[str] = []
+    try:
+        entries: List[str] = sorted(os.listdir(root))
+    except PermissionError:
+        return [f"{prefix}[permission denied]"]
+    dirs: List[str] = [
+        e for e in entries
+        if not e.startswith(".") and os.path.isdir(os.path.join(root, e))
+    ]
+    files: List[str] = [
+        e for e in entries
+        if not e.startswith(".") and os.path.isfile(os.path.join(root, e))
+    ]
+    for f in files:
+        lines.append(f"{prefix}{f}")
+    for d in dirs:
+        lines.append(f"{prefix}{d}/")
+        if max_depth > 1:
+            lines.extend(p_build_dir_tree(os.path.join(root, d), max_depth - 1, prefix + "  "))
+    return lines
+
+
+@typechecked
+def resolve_context_paths(context_paths: List[ContextPath]) -> str:
+    """Read files / build directory trees for each context path."""
+    if not context_paths:
+        return ""
+    sections: List[str] = []
+    for cp in context_paths:
+        path: str = cp.path
+        cp_type: str = cp.type
+        if not path or not os.path.exists(path):
+            sections.append(f"[Context: {path} — not found]")
+            continue
+        if cp_type == "file" and os.path.isfile(path):
+            try:
+                with open(path, "r", errors="replace") as f:
+                    content: str = f.read(MAX_FILE_READ_BYTES)
+                sections.append(
+                    f'<context_file path="{path}">\n{content}\n</context_file>'
+                )
+            except Exception as e:
+                sections.append(f"[Context: {path} — error reading: {e}]")
+        elif cp_type == "directory" and os.path.isdir(path):
+            tree = p_build_dir_tree(path, max_depth=DIR_TREE_MAX_DEPTH)
+            sections.append(
+                f'<context_directory path="{path}">\n{chr(10).join(tree)}\n</context_directory>'
+            )
+        else:
+            sections.append(f"[Context: {path} — type mismatch]")
+    return "\n\n".join(sections)
+
+
+@typechecked
+def resolve_forced_tools(forced_tools: List[str]) -> str:
+    """Build a <forced_tools> prompt block from a list of tool names."""
+    if not forced_tools:
+        return ""
+    lines: List[str] = [f"- {name}" for name in forced_tools]
+    return (
+        "<forced_tools>\n"
+        "The user explicitly requested these tools be used. "
+        "Prioritize using them to address the user's request.\n"
+        + "\n".join(lines)
+        + "\n</forced_tools>"
+    )
+
+
+@typechecked
+def resolve_attached_skills(attached_skills: List[SkillMeta]) -> str:
+    """Format attached skills into prompt sections."""
+    if not attached_skills:
+        return ""
+    sections: List[str] = []
+    for skill in attached_skills:
+        name: str = skill.name
+        content: str = skill.content
+        if content:
+            sections.append(f"[Using skill: {name}]\n\n{content}")
+    return "\n\n".join(sections)
\ No newline at end of file