merge(cli): références d'attachments + zone chat redimensionnable — #188 (QA verte)

crates/app-tauri/src/chat.rs

@@ -256,8 +256,22 @@ fn progress_entity_key(progress: &ReplyProgressDto) -> Option<String> {
 
 fn reply_chunk_bytes(chunk: &ReplyChunk) -> usize {
     match chunk {
-        ReplyChunk::UserPrompt { text, attachments } => {
-            text.len() + attachments.iter().map(String::len).sum::<usize>()
+        ReplyChunk::UserPrompt {
+            text,
+            attachments,
+            attachment_refs,
+        } => {
+            text.len()
+                + attachments.iter().map(String::len).sum::<usize>()
+                + attachment_refs
+                    .iter()
+                    .map(|attachment| {
+                        attachment.reference.len()
+                            + attachment.filename.len()
+                            + attachment.mime.len()
+                            + attachment.readable_path.len()
+                    })
+                    .sum::<usize>()
         }
         ReplyChunk::TextDelta { text } => text.len(),
         ReplyChunk::ToolActivity { label } => label.len(),

crates/app-tauri/src/commands.rs

@@ -48,7 +48,7 @@ use crate::dto::{
     AppExitWorkGuardStateDto, AssignSkillRequestDto, AttachBackgroundTaskResultDto,
     AttachLiveAgentRequestDto, AttachLiveAgentResponseDto, BackgroundTaskDto, CellKind,
     ChangeAgentProfileDto, ChangeAgentProfileRequestDto, ChatAttachmentDto, ChatAttachmentInputDto,
-    ChatDraftScopeRequestDto, CloneOpenCodeProfileFromSeedRequestDto,
+    ChatDraftScopeRequestDto, ChatPromptAttachmentDto, CloneOpenCodeProfileFromSeedRequestDto,
     CloneProfileFromSeedRequestDto, ConfigureProfilesRequestDto, ConversationDetailsDto,
     CreateAgentFromTemplateRequestDto, CreateAgentRequestDto, CreateLayoutRequestDto,
     CreateLayoutResultDto, CreateMemoryRequestDto, CreateProjectRequestDto, CreateSkillRequestDto,
@@ -2356,7 +2356,9 @@ pub async fn agent_send(
         attachments.unwrap_or_default(),
     )
     .await?;
-    let prompt_for_model = prompt_with_imported_attachments(&prompt, &imported_attachments);
+    let attachment_refs = chat_prompt_attachment_refs(&imported_attachments);
+    let prompt_for_model =
+        prompt_with_imported_attachments(&prompt, &imported_attachments, &attachment_refs);
     let attachment_labels = imported_attachments
         .iter()
         .map(|attachment| attachment.filename.clone())
@@ -2369,6 +2371,7 @@ pub async fn agent_send(
         ReplyChunk::UserPrompt {
             text: prompt.clone(),
             attachments: attachment_labels,
+            attachment_refs,
         },
     );
 
@@ -2629,15 +2632,21 @@ fn decode_attachment_content_base64(raw: &str) -> Result<Vec<u8>, ErrorDto> {
         })
 }
 
-fn prompt_with_imported_attachments(prompt: &str, attachments: &[ChatAttachmentDto]) -> String {
+fn prompt_with_imported_attachments(
+    prompt: &str,
+    attachments: &[ChatAttachmentDto],
+    refs: &[ChatPromptAttachmentDto],
+) -> String {
     if attachments.is_empty() {
         return prompt.to_owned();
     }
     let mut out = String::with_capacity(prompt.len() + attachments.len() * 160);
     out.push_str(prompt);
     out.push_str("\n\nAttachments imported by IdeA and readable from the agent sandbox:\n");
-    for attachment in attachments {
-        out.push_str("- id: ");
+    for (attachment, attachment_ref) in attachments.iter().zip(refs.iter()) {
+        out.push_str("- ");
+        out.push_str(&attachment_ref.reference);
+        out.push_str(" id: ");
         out.push_str(&attachment.id);
         out.push_str("; file: ");
         out.push_str(&attachment.filename);
@@ -2652,6 +2661,81 @@ fn prompt_with_imported_attachments(prompt: &str, attachments: &[ChatAttachmentD
     out
 }
 
+fn chat_prompt_attachment_refs(attachments: &[ChatAttachmentDto]) -> Vec<ChatPromptAttachmentDto> {
+    let mut image_count = 0usize;
+    let mut file_count = 0usize;
+    attachments
+        .iter()
+        .map(|attachment| {
+            let reference = if attachment.mime.starts_with("image/") {
+                image_count += 1;
+                format!("[image {image_count}]")
+            } else {
+                file_count += 1;
+                format!("[file {file_count}]")
+            };
+            ChatPromptAttachmentDto {
+                reference,
+                filename: attachment.filename.clone(),
+                mime: attachment.mime.clone(),
+                size_bytes: attachment.size_bytes,
+                readable_path: attachment.readable_path.clone(),
+            }
+        })
+        .collect()
+}
+
+#[cfg(test)]
+mod chat_prompt_attachment_projection_tests {
+    use super::*;
+
+    fn attachment(filename: &str, mime: &str, size_bytes: u64) -> ChatAttachmentDto {
+        ChatAttachmentDto {
+            id: format!("id-{filename}"),
+            filename: filename.to_owned(),
+            mime: mime.to_owned(),
+            size_bytes,
+            source_kind: domain::ChatAttachmentSourceKind::Clipboard,
+            storage_path: format!("agent-chat/session/id-{filename}-{filename}"),
+            readable_path: format!("/project/.ideai/attachments/agent-chat/session/{filename}"),
+            created_at: size_bytes,
+        }
+    }
+
+    #[test]
+    fn chat_prompt_attachment_refs_follow_import_order_and_kind_counters() {
+        let attachments = vec![
+            attachment("first.png", "image/png", 10),
+            attachment("notes.pdf", "application/pdf", 20),
+            attachment("second.jpg", "image/jpeg", 30),
+        ];
+
+        let refs = chat_prompt_attachment_refs(&attachments);
+
+        assert_eq!(refs[0].reference, "[image 1]");
+        assert_eq!(refs[0].filename, "first.png");
+        assert_eq!(refs[1].reference, "[file 1]");
+        assert_eq!(refs[1].filename, "notes.pdf");
+        assert_eq!(refs[2].reference, "[image 2]");
+        assert_eq!(refs[2].filename, "second.jpg");
+    }
+
+    #[test]
+    fn prompt_with_imported_attachments_uses_canonical_refs() {
+        let attachments = vec![
+            attachment("first.png", "image/png", 10),
+            attachment("notes.pdf", "application/pdf", 20),
+        ];
+        let refs = chat_prompt_attachment_refs(&attachments);
+
+        let prompt = prompt_with_imported_attachments("describe", &attachments, &refs);
+
+        assert!(prompt.contains("- [image 1] id: id-first.png; file: first.png"));
+        assert!(prompt.contains("- [file 1] id: id-notes.pdf; file: notes.pdf"));
+        assert!(prompt.contains("; path: /project/.ideai/attachments/agent-chat/session/notes.pdf"));
+    }
+}
+
 /// `cancel_resume` — annule la **reprise automatique** armée pour un agent limité
 /// (ARCHITECTURE §21.1-4, fenêtre annulable).
 ///

crates/app-tauri/tests/chat_bridge.rs

@@ -106,8 +106,22 @@ fn progress_chunk_with_id(
 
 fn chunk_bytes(chunk: &ReplyChunk) -> usize {
     match chunk {
-        ReplyChunk::UserPrompt { text, attachments } => {
-            text.len() + attachments.iter().map(String::len).sum::<usize>()
+        ReplyChunk::UserPrompt {
+            text,
+            attachments,
+            attachment_refs,
+        } => {
+            text.len()
+                + attachments.iter().map(String::len).sum::<usize>()
+                + attachment_refs
+                    .iter()
+                    .map(|attachment| {
+                        attachment.reference.len()
+                            + attachment.filename.len()
+                            + attachment.mime.len()
+                            + attachment.readable_path.len()
+                    })
+                    .sum::<usize>()
         }
         ReplyChunk::TextDelta { text } => text.len(),
         ReplyChunk::ToolActivity { label } => label.len(),

crates/app-tauri/tests/dto_chat.rs

@@ -8,9 +8,9 @@
 
 use app_tauri_lib::dto::{
     CellKind, ChatAttachmentDto, ChatAttachmentInputDto, ChatDraftScopeRequestDto,
-    ImportChatAttachmentsRequestDto, ImportChatAttachmentsResponseDto, ReadChatDraftResponseDto,
-    ReattachChatDto, ReplyChunk, ReplyProgressDto, ReplyProgressKindDto, ReplyProgressSourceDto,
-    ReplyProgressStageDto, SaveChatDraftRequestDto, TerminalSessionDto,
+    ChatPromptAttachmentDto, ImportChatAttachmentsRequestDto, ImportChatAttachmentsResponseDto,
+    ReadChatDraftResponseDto, ReattachChatDto, ReplyChunk, ReplyProgressDto, ReplyProgressKindDto,
+    ReplyProgressSourceDto, ReplyProgressStageDto, SaveChatDraftRequestDto, TerminalSessionDto,
 };
 use application::{LaunchAgentOutput, StructuredSessionDescriptor};
 use domain::project::ProjectPath;
@@ -28,6 +28,7 @@ fn reply_chunk_user_prompt_serialises_exact_camel_case() {
     let v = serde_json::to_value(ReplyChunk::UserPrompt {
         text: "run tests".into(),
         attachments: Vec::new(),
+        attachment_refs: Vec::new(),
     })
     .unwrap();
     assert_eq!(v, json!({ "kind": "userPrompt", "text": "run tests" }));
@@ -38,6 +39,13 @@ fn reply_chunk_user_prompt_serialises_attachment_labels() {
     let v = serde_json::to_value(ReplyChunk::UserPrompt {
         text: "describe this".into(),
         attachments: vec!["clipboard.png".into()],
+        attachment_refs: vec![ChatPromptAttachmentDto {
+            reference: "[image 1]".into(),
+            filename: "clipboard.png".into(),
+            mime: "image/png".into(),
+            size_bytes: 9,
+            readable_path: "/project/.ideai/attachments/agent-chat/s/attach-1-clipboard.png".into(),
+        }],
     })
     .unwrap();
     assert_eq!(
@@ -45,7 +53,14 @@ fn reply_chunk_user_prompt_serialises_attachment_labels() {
         json!({
             "kind": "userPrompt",
             "text": "describe this",
-            "attachments": ["clipboard.png"]
+            "attachments": ["clipboard.png"],
+            "attachmentRefs": [{
+                "reference": "[image 1]",
+                "filename": "clipboard.png",
+                "mime": "image/png",
+                "sizeBytes": 9,
+                "readablePath": "/project/.ideai/attachments/agent-chat/s/attach-1-clipboard.png"
+            }]
         })
     );
 }
@@ -128,6 +143,14 @@ fn reply_chunk_round_trips_through_json_for_every_variant() {
         ReplyChunk::UserPrompt {
             text: "u".into(),
             attachments: vec!["clipboard.png".into()],
+            attachment_refs: vec![ChatPromptAttachmentDto {
+                reference: "[image 1]".into(),
+                filename: "clipboard.png".into(),
+                mime: "image/png".into(),
+                size_bytes: 9,
+                readable_path: "/project/.ideai/attachments/agent-chat/s/attach-1-clipboard.png"
+                    .into(),
+            }],
         },
         ReplyChunk::TextDelta { text: "x".into() },
         ReplyChunk::ToolActivity {
@@ -168,7 +191,8 @@ fn reply_chunk_deserialises_from_camel_case_wire_payload() {
         back,
         ReplyChunk::UserPrompt {
             text: "hi".into(),
-            attachments: Vec::new()
+            attachments: Vec::new(),
+            attachment_refs: Vec::new()
         }
     );
 }
@@ -343,6 +367,7 @@ fn reattach_chat_dto_serialises_camel_case_with_typed_scrollback() {
             ReplyChunk::UserPrompt {
                 text: "Hi".into(),
                 attachments: Vec::new(),
+                attachment_refs: Vec::new(),
             },
             ReplyChunk::TextDelta { text: "Hi".into() },
             ReplyChunk::Final {

crates/backend/src/dto.rs

@@ -3206,6 +3206,22 @@ pub struct ChatAttachmentDto {
     pub created_at: u64,
 }
 
+/// Canonical attachment projection attached to a streamed user prompt.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct ChatPromptAttachmentDto {
+    /// Stable textual reference inserted in the model prompt, e.g. `[file 1]`.
+    pub reference: String,
+    /// Original display filename.
+    pub filename: String,
+    /// MIME type.
+    pub mime: String,
+    /// Size in bytes.
+    pub size_bytes: u64,
+    /// Absolute managed path readable by the target agent sandbox.
+    pub readable_path: String,
+}
+
 impl From<domain::ChatAttachment> for ChatAttachmentDto {
     fn from(value: domain::ChatAttachment) -> Self {
         Self {
@@ -3359,6 +3375,9 @@ pub enum ReplyChunk {
         /// Display labels for attachments submitted with the prompt.
         #[serde(default, skip_serializing_if = "Vec::is_empty")]
         attachments: Vec<String>,
+        /// Canonical attachment references for this prompt, in backend import order.
+        #[serde(default, skip_serializing_if = "Vec::is_empty")]
+        attachment_refs: Vec<ChatPromptAttachmentDto>,
     },
     /// An assistant text fragment (incremental chat rendering).
     #[serde(rename_all = "camelCase")]

frontend/src/domain/index.ts

@@ -1691,8 +1691,21 @@ export interface ReplyProgress {
   toolName?: string;
 }
 
+export interface ChatPromptAttachment {
+  reference: string;
+  filename: string;
+  mime?: string;
+  sizeBytes?: number;
+  readablePath?: string;
+}
+
 export type ReplyChunk =
-  | { kind: "userPrompt"; text: string; attachments?: string[] }
+  | {
+      kind: "userPrompt";
+      text: string;
+      attachments?: string[];
+      attachmentRefs?: ChatPromptAttachment[];
+    }
   | { kind: "textDelta"; text: string }
   | { kind: "toolActivity"; label: string }
   | { kind: "progress"; progress: ReplyProgress }

frontend/src/features/agents/CustomAgentChatView.test.tsx

@@ -78,7 +78,7 @@ describe("CustomAgentChatView", () => {
     __resetProjectCliInteractionActivityForTests();
   });
 
-  it("repaints attachment labels from user prompt scrollback", async () => {
+  it("repaints compact attachment refs from legacy user prompt scrollback", async () => {
     const agent = {
       launchAgentChat: vi.fn(),
       reattachAgentChat: vi.fn(async (sessionId: string) => ({
@@ -119,7 +119,68 @@ describe("CustomAgentChatView", () => {
     );
 
     expect(await screen.findByText("describe this")).toBeTruthy();
-    expect(screen.getByText("Fichier: clipboard.png")).toBeTruthy();
+    expect(screen.getByText("[image 1] clipboard.png")).toBeTruthy();
+  });
+
+  it("prefers canonical attachment refs from user prompt scrollback", async () => {
+    const agent = {
+      launchAgentChat: vi.fn(),
+      reattachAgentChat: vi.fn(async (sessionId: string) => ({
+        sessionId,
+        scrollback: [
+          {
+            kind: "userPrompt" as const,
+            text: "compare these",
+            attachments: ["screenshot.png", "error.log"],
+            attachmentRefs: [
+              {
+                reference: "[image 1]",
+                filename: "screenshot.png",
+                mime: "image/png",
+                sizeBytes: 12,
+                readablePath: "/repo/.ideai/attachments/screenshot.png",
+              },
+              {
+                reference: "[file 1]",
+                filename: "error.log",
+                mime: "text/plain",
+                sizeBytes: 34,
+                readablePath: "/repo/.ideai/attachments/error.log",
+              },
+            ],
+          },
+        ],
+      })),
+      sendAgentChat: vi.fn(async () => {}),
+      cancelAgentChat: vi.fn(async () => {}),
+      closeAgentChat: vi.fn(async () => {}),
+    };
+
+    render(
+      <DIProvider
+        gateways={{
+          agent,
+          system: { pickFile: vi.fn(async () => null) },
+        } as unknown as Gateways}
+      >
+        <CustomAgentChatView
+          projectId="project-1"
+          agentId="agent-1"
+          agentName="Worker"
+          profile={profile}
+          cwd="/repo"
+          nodeId="node-1"
+          sessionId="chat-session-1"
+          conversationId="conversation-1"
+          onSessionId={vi.fn()}
+          onConversationId={vi.fn()}
+        />
+      </DIProvider>,
+    );
+
+    expect(await screen.findByText("compare these")).toBeTruthy();
+    expect(screen.getByText("[image 1] screenshot.png")).toBeTruthy();
+    expect(screen.getByText("[file 1] error.log")).toBeTruthy();
   });
 
   it("detaches on unmount then reattaches with missed scrollback chunks", async () => {
@@ -2342,7 +2403,7 @@ describe("CustomAgentChatView", () => {
       },
     );
     expect(screen.getByText("Pièce jointe")).toBeTruthy();
-    expect(screen.getByText("Fichier: paste-image.png")).toBeTruthy();
+    expect(screen.getByText("[image 1] paste-image.png")).toBeTruthy();
   });
 
   it("accepts pasted generic files exposed only through clipboardData.files", async () => {
@@ -2503,7 +2564,7 @@ describe("CustomAgentChatView", () => {
       },
     );
     expect(screen.getByText("prefix inserted")).toBeTruthy();
-    expect(screen.getByText("Fichier: mixed.txt")).toBeTruthy();
+    expect(screen.getByText("[file 1] mixed.txt")).toBeTruthy();
   });
 
   it("deduplicates clipboard files by metadata across clipboard sources and repeated paste", async () => {

frontend/src/features/agents/CustomAgentChatView.tsx

@@ -17,6 +17,7 @@ import {
 
 import type {
   AgentProfile,
+  ChatPromptAttachment,
   GatewayError,
   ReplyChunk,
   ReplyProgress,
@@ -50,7 +51,7 @@ export interface CustomAgentChatViewProps {
 }
 
 type ChatTurn =
-  | { role: "user"; text: string; attachments?: string[] }
+  | { role: "user"; text: string; attachments?: ChatPromptAttachment[] }
   | { role: "agent"; text: string; pending?: boolean }
   | { role: "tool"; label: string }
   | { role: "progress"; progress: ReplyProgress; settled?: boolean }
@@ -158,10 +159,62 @@ function attachmentLabels(value: unknown): string[] {
     : [];
 }
 
+function isImageFilename(filename: string): boolean {
+  return /\.(apng|avif|gif|jpe?g|png|svg|webp)$/i.test(filename.trim());
+}
+
+function fallbackAttachmentRefs(labels: string[]): ChatPromptAttachment[] {
+  let imageCount = 0;
+  let fileCount = 0;
+  return labels.map((filename) => {
+    const image = isImageFilename(filename);
+    const reference = image ? `[image ${++imageCount}]` : `[file ${++fileCount}]`;
+    return { reference, filename };
+  });
+}
+
+function attachmentRefs(value: unknown, labels: string[] = []): ChatPromptAttachment[] {
+  if (Array.isArray(value)) {
+    const refs = value
+      .map((item): ChatPromptAttachment | null => {
+        if (!item || typeof item !== "object") return null;
+        const record = item as Record<string, unknown>;
+        const reference = optionalString(record.reference);
+        const filename = optionalString(record.filename);
+        if (!reference || !filename) return null;
+        return {
+          reference,
+          filename,
+          mime: optionalString(record.mime),
+          sizeBytes: typeof record.sizeBytes === "number" ? record.sizeBytes : undefined,
+          readablePath: optionalString(record.readablePath),
+        };
+      })
+      .filter((item): item is ChatPromptAttachment => Boolean(item));
+    if (refs.length > 0) return refs;
+  }
+  return fallbackAttachmentRefs(labels);
+}
+
+function attachmentRefsFromDrafts(attachments: AttachmentDraft[]): ChatPromptAttachment[] {
+  let imageCount = 0;
+  let fileCount = 0;
+  return attachments.map((attachment) => {
+    const mime = attachment.input.mime ?? "";
+    const image = mime.startsWith("image/") || (!mime && isImageFilename(attachment.label));
+    const reference = image ? `[image ${++imageCount}]` : `[file ${++fileCount}]`;
+    return {
+      reference,
+      filename: attachment.label,
+      mime: attachment.input.mime,
+    };
+  });
+}
+
 function appendUserPrompt(
   turns: ChatTurn[],
   text: string,
-  attachments: string[] = [],
+  attachments: ChatPromptAttachment[] = [],
 ): ChatTurn[] {
   const last = turns[turns.length - 1];
   if (
@@ -589,7 +642,7 @@ function foldChunk(state: ChatViewState, raw: unknown): ChatViewState {
         turns: appendUserPrompt(
           turns,
           String(raw.text ?? raw.prompt ?? ""),
-          attachmentLabels(raw.attachments),
+          attachmentRefs(raw.attachmentRefs, attachmentLabels(raw.attachments)),
         ),
         entityProgressMap: state.entityProgressMap,
       };
@@ -1359,7 +1412,7 @@ export function CustomAgentChatView({
     }
     const outgoingAttachments = attachments;
     const attachmentInputs = outgoingAttachments.map((item) => item.input);
-    const attachmentLabels = outgoingAttachments.map((item) => item.label);
+    const attachmentRefs = attachmentRefsFromDrafts(outgoingAttachments);
     const displayText = text || "Pièce jointe";
     const interactionId = `${agentId}:${++interactionSeqRef.current}`;
     activeInteractionIdRef.current = interactionId;
@@ -1380,7 +1433,7 @@ export function CustomAgentChatView({
         {
           role: "user",
           text: displayText,
-          ...(attachmentLabels.length > 0 ? { attachments: attachmentLabels } : {}),
+          ...(attachmentRefs.length > 0 ? { attachments: attachmentRefs } : {}),
         },
       ],
       entityProgressMap: prev.entityProgressMap,
@@ -1855,8 +1908,8 @@ function ChatBubble({
         {user && turn.attachments && turn.attachments.length > 0 && (
           <div className="mt-1 flex flex-col gap-0.5 text-xs text-muted">
             {turn.attachments.map((attachment) => (
-              <p key={attachment} className="truncate">
-                Fichier: {attachment}
+              <p key={`${attachment.reference}-${attachment.filename}`} className="truncate">
+                {attachment.reference} {attachment.filename}
               </p>
             ))}
           </div>

frontend/src/features/layout/LayoutGrid.chat.test.tsx

@@ -180,6 +180,37 @@ describe("LayoutGrid custom agent CLI (#147)", () => {
     expect(screen.getAllByText(/mock-attachment.txt/).length).toBeGreaterThan(0);
   });
 
+  it("resizes the custom CLI chat locally per cell and can reset to the default size", async () => {
+    const gateways = await seeded(structuredProfile);
+    const layout = gateways.layout as MockLayoutGateway;
+    const tree = await layout.loadLayout("p1");
+    const leafId = leaves(tree)[0].id;
+    window.localStorage.setItem(`idea.agent-cell-mode.p1.${leafId}`, "custom");
+
+    renderGrid(gateways);
+
+    const shell = await screen.findByTestId("custom-agent-chat-shell");
+    expect(shell.style.width).toBe("100%");
+    expect(window.localStorage.getItem(`idea.custom-chat-size.p1.${leafId}`)).toBeNull();
+
+    fireEvent.mouseDown(screen.getByRole("button", { name: `resize custom chat ${leafId}` }), {
+      clientX: 0,
+      clientY: 0,
+    });
+    fireEvent.mouseMove(window, { clientX: 640, clientY: 420 });
+    fireEvent.mouseUp(window);
+
+    await waitFor(() => expect(shell.style.width).toBe("640px"));
+    expect(shell.style.height).toBe("420px");
+    expect(JSON.parse(window.localStorage.getItem(`idea.custom-chat-size.p1.${leafId}`) ?? "{}"))
+      .toEqual({ width: 640, height: 420 });
+
+    fireEvent.click(screen.getByRole("button", { name: `reset custom chat size ${leafId}` }));
+
+    await waitFor(() => expect(shell.style.width).toBe("100%"));
+    expect(window.localStorage.getItem(`idea.custom-chat-size.p1.${leafId}`)).toBeNull();
+  });
+
   it("opens the custom CLI even when the agent already has a structured background session (#169)", async () => {
     const layout = new MockLayoutGateway();
     const agent = new MockAgentGateway();

frontend/src/features/layout/LayoutGrid.tsx

@@ -16,7 +16,7 @@
  * {@link normalizeWeights} function, kept out of the render for testability.
  */
 
-import { useCallback, useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useRef, useState, type MouseEvent as ReactMouseEvent } from "react";
 
 import type { Agent, AgentProfile } from "@/domain";
 import type { LayoutNode } from "@/domain";
@@ -407,6 +407,50 @@ const CELL_Z = {
   turnActions: 6,
 } as const;
 
+const CUSTOM_CHAT_MIN_WIDTH = 360;
+const CUSTOM_CHAT_MIN_HEIGHT = 280;
+const CUSTOM_CHAT_MAX_WIDTH = 1200;
+const CUSTOM_CHAT_MAX_HEIGHT = 900;
+
+interface CustomChatSize {
+  width: number;
+  height: number;
+}
+
+function clampCustomChatSize(size: CustomChatSize): CustomChatSize {
+  const viewportWidth =
+    typeof window === "undefined" ? CUSTOM_CHAT_MAX_WIDTH : window.innerWidth - 24;
+  const viewportHeight =
+    typeof window === "undefined" ? CUSTOM_CHAT_MAX_HEIGHT : window.innerHeight - 24;
+  return {
+    width: Math.round(
+      Math.min(
+        Math.max(size.width, CUSTOM_CHAT_MIN_WIDTH),
+        Math.max(CUSTOM_CHAT_MIN_WIDTH, Math.min(CUSTOM_CHAT_MAX_WIDTH, viewportWidth)),
+      ),
+    ),
+    height: Math.round(
+      Math.min(
+        Math.max(size.height, CUSTOM_CHAT_MIN_HEIGHT),
+        Math.max(CUSTOM_CHAT_MIN_HEIGHT, Math.min(CUSTOM_CHAT_MAX_HEIGHT, viewportHeight)),
+      ),
+    ),
+  };
+}
+
+function readCustomChatSize(storageKey: string): CustomChatSize | null {
+  if (typeof window === "undefined") return null;
+  try {
+    const raw = window.localStorage.getItem(storageKey);
+    if (!raw) return null;
+    const parsed = JSON.parse(raw) as Partial<CustomChatSize>;
+    if (typeof parsed.width !== "number" || typeof parsed.height !== "number") return null;
+    return clampCustomChatSize({ width: parsed.width, height: parsed.height });
+  } catch {
+    return null;
+  }
+}
+
 function LeafView({
   id,
   session,
@@ -526,6 +570,54 @@ function LeafView({
     },
     [cellModeStorageKey],
   );
+  const customChatSizeStorageKey = `idea.custom-chat-size.${projectId}.${id}`;
+  const [customChatSize, setCustomChatSizeState] = useState<CustomChatSize | null>(() =>
+    readCustomChatSize(customChatSizeStorageKey),
+  );
+  const setCustomChatSize = useCallback(
+    (size: CustomChatSize | null) => {
+      setCustomChatSizeState(size);
+      if (typeof window === "undefined") return;
+      try {
+        if (size) {
+          window.localStorage.setItem(customChatSizeStorageKey, JSON.stringify(size));
+        } else {
+          window.localStorage.removeItem(customChatSizeStorageKey);
+        }
+      } catch {
+        /* local preference only */
+      }
+    },
+    [customChatSizeStorageKey],
+  );
+  const startCustomChatResize = useCallback(
+    (event: ReactMouseEvent<HTMLButtonElement>) => {
+      const container = event.currentTarget.closest<HTMLElement>("[data-custom-chat-shell]");
+      if (!container) return;
+      event.preventDefault();
+      event.stopPropagation();
+      const rect = container.getBoundingClientRect();
+      const startX = event.clientX;
+      const startY = event.clientY;
+      const startWidth = customChatSize?.width ?? rect.width;
+      const startHeight = customChatSize?.height ?? rect.height;
+      const onMove = (moveEvent: MouseEvent) => {
+        setCustomChatSize(
+          clampCustomChatSize({
+            width: startWidth + moveEvent.clientX - startX,
+            height: startHeight + moveEvent.clientY - startY,
+          }),
+        );
+      };
+      const onUp = () => {
+        window.removeEventListener("mousemove", onMove);
+        window.removeEventListener("mouseup", onUp);
+      };
+      window.addEventListener("mousemove", onMove);
+      window.addEventListener("mouseup", onUp);
+    },
+    [customChatSize, setCustomChatSize],
+  );
   const [pendingModeSwitch, setPendingModeSwitch] =
     useState<PendingModeSwitch | null>(null);
   const [trustedCustomCli, setTrustedCustomCli] =
@@ -1100,7 +1192,7 @@ function LeafView({
         minWidth: 0,
         border: "1px solid #2a2a2a",
         boxSizing: "border-box",
-        overflow: "hidden",
+        overflow: customChatSize ? "visible" : "hidden",
       }}
     >
       <div
@@ -1464,20 +1556,85 @@ function LeafView({
             onRefresh={() => void refreshStoppedAgentState()}
           />
         ) : agentId && cellMode === "custom" && effectiveCustomCliAvailable && customCliAgent && customCliProfile ? (
-          <CustomAgentChatView
-            key={`${id}-${agentId}-custom`}
-            projectId={projectId}
-            agentId={agentId}
-            agentName={customCliAgent.name}
-            profile={customCliProfile}
-            cwd={cwd}
-            layoutId={layoutId}
-            nodeId={id}
-            sessionId={session}
-            conversationId={conversationId}
-            onSessionId={(sid) => void setSessionWithInstrumentation("custom", sid)}
-            onConversationId={(cid) => void vm.setCellConversation(id, cid)}
-          />
+          <div
+            data-custom-chat-shell
+            data-testid="custom-agent-chat-shell"
+            style={{
+              position: customChatSize ? "absolute" : "relative",
+              top: 0,
+              left: 0,
+              zIndex: customChatSize ? 2 : 0,
+              width: customChatSize ? customChatSize.width : "100%",
+              height: customChatSize ? customChatSize.height : "100%",
+              minWidth: CUSTOM_CHAT_MIN_WIDTH,
+              minHeight: CUSTOM_CHAT_MIN_HEIGHT,
+              maxWidth: "calc(100vw - 24px)",
+              maxHeight: "calc(100vh - 24px)",
+              boxShadow: customChatSize ? "0 18px 48px rgba(0, 0, 0, 0.42)" : undefined,
+            }}
+          >
+            <CustomAgentChatView
+              key={`${id}-${agentId}-custom`}
+              projectId={projectId}
+              agentId={agentId}
+              agentName={customCliAgent.name}
+              profile={customCliProfile}
+              cwd={cwd}
+              layoutId={layoutId}
+              nodeId={id}
+              sessionId={session}
+              conversationId={conversationId}
+              onSessionId={(sid) => void setSessionWithInstrumentation("custom", sid)}
+              onConversationId={(cid) => void vm.setCellConversation(id, cid)}
+            />
+            {customChatSize && (
+              <button
+                type="button"
+                aria-label={`reset custom chat size ${id}`}
+                title="Reset chat size"
+                onClick={() => setCustomChatSize(null)}
+                style={{
+                  position: "absolute",
+                  right: 30,
+                  bottom: 6,
+                  zIndex: 30,
+                  border: "1px solid var(--color-border, #3a3a3a)",
+                  borderRadius: 3,
+                  background: "var(--color-surface, #1e1e1e)",
+                  color: "var(--color-content, #e0e0e0)",
+                  cursor: "pointer",
+                  fontSize: 11,
+                  padding: "1px 6px",
+                }}
+              >
+                Reset
+              </button>
+            )}
+            <button
+              type="button"
+              aria-label={`resize custom chat ${id}`}
+              title="Resize chat"
+              onMouseDown={startCustomChatResize}
+              style={{
+                position: "absolute",
+                right: 6,
+                bottom: 6,
+                zIndex: 30,
+                width: 16,
+                height: 16,
+                border: "1px solid var(--color-border, #3a3a3a)",
+                borderRadius: 3,
+                background: "var(--color-surface, #1e1e1e)",
+                color: "var(--color-muted, #9aa7b4)",
+                cursor: "nwse-resize",
+                fontSize: 11,
+                lineHeight: "12px",
+                padding: 0,
+              }}
+            >
+              ↘
+            </button>
+          </div>
         ) : (
           <TerminalView
             key={`${id}-${agentId ?? "plain"}-${attachGen}`}