diff --git a/packages/plugin/src/tui/context.ts b/packages/plugin/src/tui/context.ts
index fe641b39d5e9..754021c2d0b4 100644
--- a/packages/plugin/src/tui/context.ts
+++ b/packages/plugin/src/tui/context.ts
@@ -17,6 +17,7 @@ import type {
   ProviderInfo,
   ReferenceInfo,
   SessionInfo,
+  SessionMessageAssistant,
   SessionMessageInfo,
   SessionInboxInfo,
   ShellInfo,
@@ -24,7 +25,7 @@ import type {
   VcsInfo,
 } from "@opencode/client"
 import type { ResolvedTheme } from "@opencode/theme/tui"
-import type { CliRenderer, KeyEvent, MarkdownCodeBlockRenderer, Renderable } from "@opentui/core"
+import type { CliRenderer, KeyEvent, MarkdownCodeBlockRenderer, Renderable, RGBA } from "@opentui/core"
 import type { JSX } from "@opentui/solid"
 import type { Store } from "solid-js/store"
 
@@ -60,6 +61,27 @@ interface LocationCollection<Value> {
 
 type OpenCodeEventMap = { [Type in OpenCodeEvent["type"]]: Extract<OpenCodeEvent, { type: Type }> }
 
+/** One part of an assistant message: text, reasoning or a tool call. */
+export type SessionPart = SessionMessageAssistant["content"][number]
+
+/** How much of its model's context window a session's last turn used. */
+export interface SessionUsage {
+  /** Input, output, reasoning and cache tokens of the last assistant turn with usage. */
+  readonly tokens: number
+  /** The model's context window, when the model is known. */
+  readonly limit?: number
+  /** `tokens` as a rounded percentage of `limit`. */
+  readonly percent?: number
+}
+
+/** The goal `/goal` set on a session. */
+export interface SessionGoal {
+  readonly objective: string
+  readonly status: "active" | "paused" | "complete"
+  /** Why the goal last changed. */
+  readonly reason?: string
+}
+
 export interface Data {
   readonly on: <Type extends OpenCodeEvent["type"]>(
     type: Type,
@@ -73,6 +95,17 @@ export interface Data {
     family(sessionID: string): string[]
     cost(sessionID: string): number
     status(sessionID: string): "idle" | "running"
+    /**
+     * The context window the session's last turn used, up to its revert point.
+     * Undefined until a turn reports usage. Reactive when read in a Solid computation.
+     */
+    usage(sessionID: string): SessionUsage | undefined
+    /**
+     * The session's goal, or undefined when none is set or the server has no
+     * goal plugin. Fetched on first read and kept current from the server.
+     * Reactive when read in a Solid computation.
+     */
+    goal(sessionID: string): SessionGoal | undefined
     readonly pending: {
       list(sessionID: string): SessionInboxInfo[]
       sync(sessionID: string): Promise<void>
@@ -86,6 +119,13 @@ export interface Data {
       sync(sessionID: string): Promise<void>
       invalidate(sessionID: string): void
     }
+    readonly part: {
+      /**
+       * One part of an assistant message, by the `partID` a session.part.*
+       * slot receives. Reactive when read in a Solid computation.
+       */
+      get(sessionID: string, messageID: string, partID: string): SessionPart | undefined
+    }
     readonly permission: {
       list(sessionID: string): PermissionRequest[] | undefined
       sync(sessionID: string): Promise<void>
@@ -162,6 +202,17 @@ type PromptFooterInput = {
   readonly showDetails: boolean
 }
 
+/** One message of a session transcript. */
+export interface SessionMessageInput {
+  readonly sessionID: string
+  readonly messageID: string
+}
+
+/** One part of an assistant message; read it with data.session.part.get. */
+export interface SessionPartInput extends SessionMessageInput {
+  readonly partID: string
+}
+
 export type PanelPresentation = "panel" | "fullscreen"
 
 /** Client-local state of the selected session panel. The host owns its layout and input scope. */
@@ -196,6 +247,18 @@ export interface SlotMap {
   readonly "prompt.footer.status": PromptFooterInput
   readonly "prompt.footer.file": PromptFooterInput
   readonly "session.composer.top": { readonly sessionID: string }
+  /** Above the transcript, full width. Empty by default. */
+  readonly "session.header": { readonly sessionID: string }
+  /** First child of the transcript scroll area. Empty by default. */
+  readonly "session.transcript.start": { readonly sessionID: string }
+  /** A user prompt in the transcript. */
+  readonly "session.message.user": SessionMessageInput
+  /** The agent, model and duration line closing an assistant turn. */
+  readonly "session.message.assistant.footer": SessionMessageInput
+  readonly "session.part.text": SessionPartInput
+  readonly "session.part.reasoning": SessionPartInput
+  /** One tool call; `tool` is the canonical tool name (shell, patch, subagent, read, ...). */
+  readonly "session.part.tool": SessionPartInput & { readonly tool: string }
   readonly "session.panel": PanelInput
   readonly "sidebar.content": { readonly sessionID: string }
   readonly "sidebar.footer": { readonly sessionID: string }
@@ -487,6 +550,51 @@ export interface Keymap {
   }
 }
 
+/** The kind of one transcript row, as layout rules see it. */
+export type TranscriptRowKind = "user" | "text" | "reasoning" | "tool" | "group" | "footer" | "other"
+
+/**
+ * Host layout knobs a plugin may set. Every field is optional; an unset field
+ * keeps the host default. When several active plugins set one field, the
+ * last-enabled plugin wins.
+ */
+export interface Layout {
+  /** Blank rows above a transcript row. The host default is 1. */
+  readonly rowGap?: (row: { readonly kind: TranscriptRowKind; readonly previous?: TranscriptRowKind }) => number
+  /** Horizontal padding of the transcript and the dock, in cells. The host default is 2. */
+  readonly inset?: number
+  /**
+   * The composer's chrome. "bar" is the host default: a left accent bar and a
+   * metadata row. "band" is a full-width band on raised.base with a blank row
+   * above and below the editor and the given prefix before it.
+   */
+  readonly composer?: { readonly chrome: "bar" } | { readonly chrome: "band"; readonly prefix?: string }
+  /**
+   * Transcript defaults for users who have not chosen. The user's `session`
+   * config wins over them. Fields merge across plugins one by one.
+   */
+  readonly transcript?: {
+    /** "auto" groups related tool calls into one row; "none" shows each call. The host default is "auto". */
+    readonly grouping?: "auto" | "none"
+    /** Whether reasoning shows in full. The host default is "hide". */
+    readonly thinking?: "show" | "hide"
+  }
+}
+
+/** Renders one tool call in the transcript. */
+export type ToolRender = (input: SessionPartInput & { readonly tool: string }) => JSX.Element
+
+/** Host markdown, styled with the current theme's syntax and every registered code-block renderer. */
+export type MarkdownProps = {
+  readonly content: string
+  /** True while the text may still grow, so a trailing block is not finalized. */
+  readonly streaming?: boolean
+  /** Text colour. The theme's markdown text by default. */
+  readonly fg?: RGBA
+  /** Background. The theme's base background by default. */
+  readonly bg?: RGBA
+}
+
 export interface UI {
   readonly dialog: Dialog
   readonly toast: Toast
@@ -539,6 +647,17 @@ export interface UI {
   }
   /** Claims a place in the slot tree; see SlotClaim. */
   readonly slot: (claim: SlotClaim) => () => void
+  /** Sets host layout knobs until the returned cleanup runs; see Layout. */
+  readonly layout: (layout: Layout) => () => void
+  /**
+   * Renders every call of one tool, by its canonical name (shell, patch,
+   * subagent, read, ...), until the returned cleanup runs. When several
+   * active plugins render one tool, the last-enabled one wins. A slot claim
+   * that replaces session.part.tool still wins over it.
+   */
+  readonly tool: (name: string, render: ToolRender) => () => void
+  /** The host's markdown renderer, for text that should read like the transcript. */
+  readonly Markdown: (props: MarkdownProps) => JSX.Element
 }
 
 export interface Context {
diff --git a/packages/tui/src/component/prompt/index.tsx b/packages/tui/src/component/prompt/index.tsx
index 075f037dcc55..261520e5567b 100644
--- a/packages/tui/src/component/prompt/index.tsx
+++ b/packages/tui/src/component/prompt/index.tsx
@@ -58,6 +58,7 @@ import { Keymap, type KeymapCommand } from "../../context/keymap"
 import { useInteractivity } from "../../context/interactivity"
 import { abbreviateHome } from "../../runtime"
 import { Slot } from "../../plugin/render"
+import { usePlugin } from "../../plugin/context"
 import type { SessionInbox } from "@opencode/schema/session-inbox"
 import {
   deduplicatePromptImages,
@@ -1675,7 +1676,16 @@ export function Prompt(props: PromptProps) {
   })
   const maxHeight = createMemo(() => Math.max(6, Math.floor(dimensions().height / 3)))
 
-  const promptBg = createMemo(() => theme.decrease(theme.background.raised.base))
+  const plugins = usePlugin()
+  // "band" chrome: no accent bar or metadata row; the editor sits on a
+  // raised band with a blank row above and below and an optional prefix.
+  const band = createMemo(() => {
+    const composer = plugins.layout().composer
+    return composer?.chrome === "band" ? { prefix: composer.prefix } : undefined
+  })
+  const promptBg = createMemo(() =>
+    band() ? theme.background.raised.base : theme.decrease(theme.background.raised.base),
+  )
 
   return (
     <>
@@ -1683,16 +1693,21 @@ export function Prompt(props: PromptProps) {
         <box
           width="100%"
           border={["left"]}
-          borderColor={borderHighlight()}
+          // Workaround: an OpenTUI box keeps its border once styled (setting
+          // `border` back to false leaves the bar drawn), so the band paints the
+          // bar in the band colour instead of removing it.
+          borderColor={band() ? promptBg() : borderHighlight()}
+          backgroundColor={band() ? promptBg() : undefined}
           customBorderChars={{
             ...SplitBorder.customBorderChars,
             bottomLeft: "╹",
           }}
         >
           <box
-            paddingLeft={dimensions().width < 44 ? 1 : 2}
+            paddingLeft={band() ? 0 : dimensions().width < 44 ? 1 : 2}
             paddingRight={dimensions().width < 44 ? 1 : 2}
             paddingTop={1}
+            paddingBottom={band() ? 1 : 0}
             flexShrink={0}
             backgroundColor={promptBg()}
             flexGrow={1}
@@ -1766,94 +1781,105 @@ export function Prompt(props: PromptProps) {
                 </Show>
               </box>
             </Show>
-            <textarea
-              width="100%"
-              placeholder={placeholderText()}
-              placeholderColor={theme.text.muted}
-              textColor={muted() ? theme.text.muted : theme.text.base}
-              focusedTextColor={muted() ? theme.text.muted : theme.text.base}
-              minHeight={1}
-              maxHeight={maxHeight()}
-              cursorStyle={cursorStyle()}
-              onContentChange={() => {
-                const value = input.plainText
-                setStore("prompt", "text", value)
-                auto()?.onInput(value)
-                syncExtmarksWithPromptParts()
-                setCursorVersion((value) => value + 1)
-              }}
-              onCursorChange={() => setCursorVersion((value) => value + 1)}
-              onKeyDown={(e: { preventDefault(): void }) => {
-                if (disabled()) {
-                  e.preventDefault()
-                  return
-                }
-              }}
-              onSubmit={() => {
-                if (disabled()) return
-                // IME: double-defer so the last composed character (e.g. Korean
-                // hangul) is flushed to plainText before we read it for submission.
-                setTimeout(() => setTimeout(() => submit(), 0), 0)
-              }}
-              onPaste={(event: PasteEvent) => {
-                if (disabled()) {
+            <box flexDirection="row" width="100%">
+              <Show when={band()?.prefix}>{(prefix) => <text fg={theme.text.base}>{prefix()}</text>}</Show>
+              <textarea
+                flexGrow={1}
+                flexShrink={1}
+                placeholder={placeholderText()}
+                placeholderColor={theme.text.muted}
+                textColor={muted() ? theme.text.muted : theme.text.base}
+                focusedTextColor={muted() ? theme.text.muted : theme.text.base}
+                minHeight={1}
+                maxHeight={maxHeight()}
+                cursorStyle={cursorStyle()}
+                onContentChange={() => {
+                  const value = input.plainText
+                  setStore("prompt", "text", value)
+                  auto()?.onInput(value)
+                  syncExtmarksWithPromptParts()
+                  setCursorVersion((value) => value + 1)
+                }}
+                onCursorChange={() => setCursorVersion((value) => value + 1)}
+                onKeyDown={(e: { preventDefault(): void }) => {
+                  if (disabled()) {
+                    e.preventDefault()
+                    return
+                  }
+                }}
+                onSubmit={() => {
+                  if (disabled()) return
+                  // IME: double-defer so the last composed character (e.g. Korean
+                  // hangul) is flushed to plainText before we read it for submission.
+                  setTimeout(() => setTimeout(() => submit(), 0), 0)
+                }}
+                onPaste={(event: PasteEvent) => {
+                  if (disabled()) {
+                    event.preventDefault()
+                    return
+                  }
+
+                  // Normalize line endings at the boundary
+                  // Windows ConPTY/Terminal often sends CR-only newlines in bracketed paste
+                  // Replace CRLF first, then any remaining CR
+                  const normalizedText = decodePasteBytes(event.bytes).replace(/\r\n/g, "\n").replace(/\r/g, "\n")
+
+                  // Windows Terminal <1.25 can surface image-only clipboard as an
+                  // empty bracketed paste. Windows Terminal 1.25+ does not.
+                  if (event.bytes.byteLength === 0) {
+                    keymap.dispatch("prompt.paste")
+                    return
+                  }
+
+                  // Once we cross an async boundary below, the terminal may perform its
+                  // default paste unless we suppress it first and handle insertion ourselves.
                   event.preventDefault()
-                  return
-                }
-
-                // Normalize line endings at the boundary
-                // Windows ConPTY/Terminal often sends CR-only newlines in bracketed paste
-                // Replace CRLF first, then any remaining CR
-                const normalizedText = decodePasteBytes(event.bytes).replace(/\r\n/g, "\n").replace(/\r/g, "\n")
-
-                // Windows Terminal <1.25 can surface image-only clipboard as an
-                // empty bracketed paste. Windows Terminal 1.25+ does not.
-                if (event.bytes.byteLength === 0) {
-                  keymap.dispatch("prompt.paste")
-                  return
-                }
-
-                // Once we cross an async boundary below, the terminal may perform its
-                // default paste unless we suppress it first and handle insertion ourselves.
-                event.preventDefault()
-
-                void enqueuePaste((changed) => pasteInputText(normalizedText, changed))
-              }}
-              ref={(r: TextareaRenderable) => {
-                input = r
-                Object.assign(r, {
-                  getClipboardText: (text: string) => expandPastedTextPlaceholders(text, store.prompt.pasted),
-                })
-                setInputTarget(r)
-                if (promptPartTypeId === 0) {
-                  promptPartTypeId = input.extmarks.registerType("prompt-part")
-                }
-                props.ref?.(ref)
-                setTimeout(() => {
-                  // setTimeout is a workaround and needs to be addressed properly
-                  if (!input || input.isDestroyed) return
-                  input.cursorColor = disabled() ? theme.background.raised.base : theme.text.base
-                }, 0)
-              }}
-              onMouseDown={(r: MouseEvent) => {
-                if (disabled()) {
+
+                  void enqueuePaste((changed) => pasteInputText(normalizedText, changed))
+                }}
+                ref={(r: TextareaRenderable) => {
+                  input = r
+                  Object.assign(r, {
+                    getClipboardText: (text: string) => expandPastedTextPlaceholders(text, store.prompt.pasted),
+                  })
+                  setInputTarget(r)
+                  if (promptPartTypeId === 0) {
+                    promptPartTypeId = input.extmarks.registerType("prompt-part")
+                  }
+                  props.ref?.(ref)
+                  setTimeout(() => {
+                    // setTimeout is a workaround and needs to be addressed properly
+                    if (!input || input.isDestroyed) return
+                    input.cursorColor = disabled() ? theme.background.raised.base : theme.text.base
+                  }, 0)
+                }}
+                onMouseDown={(r: MouseEvent) => {
+                  if (disabled()) {
+                    r.preventDefault()
+                    return
+                  }
+                  if (r.button !== 0) return
+                  r.target?.focus()
+                  const extmark = input.extmarks
+                    .getAtOffset(input.cursorOffset)
+                    .find((item) => store.extmarkToPart.get(item.id)?.type === "pasted")
+                  if (!extmark || !expandPastedText(extmark.id)) return
                   r.preventDefault()
-                  return
-                }
-                if (r.button !== 0) return
-                r.target?.focus()
-                const extmark = input.extmarks
-                  .getAtOffset(input.cursorOffset)
-                  .find((item) => store.extmarkToPart.get(item.id)?.type === "pasted")
-                if (!extmark || !expandPastedText(extmark.id)) return
-                r.preventDefault()
-                r.stopPropagation()
-              }}
-              focusedBackgroundColor="transparent"
-              cursorColor={disabled() ? theme.background.raised.base : theme.text.base}
-              syntaxStyle={syntax()}
-            />
-            <box flexDirection="row" flexShrink={0} paddingTop={1} gap={1} justifyContent="space-between">
+                  r.stopPropagation()
+                }}
+                focusedBackgroundColor="transparent"
+                cursorColor={disabled() ? theme.background.raised.base : theme.text.base}
+                syntaxStyle={syntax()}
+              />
+            </box>
+            <box
+              flexDirection="row"
+              flexShrink={0}
+              paddingTop={1}
+              gap={1}
+              justifyContent="space-between"
+              visible={!band()}
+            >
               <PromptMetadataRow
                 mode={store.mode}
                 agent={agentLabel()}
@@ -1873,6 +1899,7 @@ export function Prompt(props: PromptProps) {
         </box>
         <box
           height={1}
+          visible={!band()}
           border={["left"]}
           borderColor={borderHighlight()}
           customBorderChars={{
diff --git a/packages/tui/src/context/data.tsx b/packages/tui/src/context/data.tsx
index 8c7668f9a77a..54aea7e1715d 100644
--- a/packages/tui/src/context/data.tsx
+++ b/packages/tui/src/context/data.tsx
@@ -1,9 +1,13 @@
 import { createData } from "@opencode/client/solid"
 import { withMediaRefs, type LocationRef } from "@opencode/client"
 import type { Plugin } from "@opencode/plugin/tui"
+import type { SessionGoal } from "@opencode/plugin/tui/context"
+import { Goal } from "@opencode/schema/goal"
+import { onCleanup } from "solid-js"
 import { createStore } from "solid-js/store"
 import { createSimpleContext } from "./helper"
 import { useClient } from "./client"
+import { contextUsage, resolvePart } from "../util/session"
 
 export { locationKey } from "@opencode/client/solid"
 export type { FormWithLocation } from "@opencode/client/solid"
@@ -19,9 +23,16 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
       connection: client.connection,
       directory: props.directory,
     })
-    data satisfies Plugin.Context["data"]
+    const goal = createGoals({
+      // The client is replaced on reconnect, so each read resolves it anew.
+      fetch: (sessionID) => {
+        const directory = data.session.get(sessionID)?.location.directory
+        return client.api.rpc(Goal.Definition).get({ sessionID }, directory ? { location: { directory } } : undefined)
+      },
+      on: data.on,
+    })
     const [generatingTitles, setGeneratingTitles] = createStore<Record<string, boolean | undefined>>({})
-    return {
+    const value = {
       ...data,
       location: {
         ...data.location,
@@ -32,6 +43,22 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
       },
       session: {
         ...data.session,
+        part: {
+          get(sessionID: string, messageID: string, partID: string) {
+            const message = data.session.message.get(sessionID, messageID)
+            return message?.type === "assistant" ? resolvePart(message, partID) : undefined
+          },
+        },
+        usage(sessionID: string) {
+          const session = data.session.get(sessionID)
+          if (!session) return
+          return contextUsage(
+            data.session.message.list(sessionID),
+            data.location.model.list(session.location),
+            session.revert?.messageID,
+          )
+        },
+        goal: goal.get,
         title: {
           pending: (sessionID: string) => generatingTitles[sessionID] === true,
           async generate(sessionID: string) {
@@ -49,5 +76,53 @@ export const { use: useData, provider: DataProvider } = createSimpleContext({
         },
       },
     }
+    value satisfies Plugin.Context["data"]
+    return value
   },
 })
+
+/**
+ * Goals by session, from the goal plugin's RPC: fetched on a session's first read and again when the server
+ * reconnects, since changes published meanwhile were missed, and kept current from its `changed` events.
+ */
+function createGoals(input: {
+  fetch: (sessionID: string) => Promise<Goal.State | null>
+  on: ReturnType<typeof createData>["on"]
+}) {
+  // null records a session known to have no goal; a missing key is not loaded yet.
+  const [goals, setGoals] = createStore<Record<string, SessionGoal | null>>({})
+  // A change that arrives while a fetch is in flight is newer than its reply, so each change or fetch takes a turn.
+  const turns = new Map<string, number>()
+  const turn = (sessionID: string) => {
+    const next = (turns.get(sessionID) ?? 0) + 1
+    turns.set(sessionID, next)
+    return next
+  }
+  const set = (sessionID: string, goal: Goal.State | null | undefined) =>
+    setGoals(sessionID, goal ? { objective: goal.objective, status: goal.status, reason: goal.reason } : null)
+  const load = (sessionID: string) => {
+    const current = turn(sessionID)
+    // A server without the goal plugin answers with an error, and the session shows no goal.
+    void input.fetch(sessionID).then(
+      (goal) => {
+        if (turns.get(sessionID) === current) set(sessionID, goal)
+      },
+      () => undefined,
+    )
+  }
+  onCleanup(
+    input.on(`rpc.${Goal.Definition.id}.changed`, (event) => {
+      const payload = event.data as { sessionID: string; goal: Goal.State | null }
+      if (!turns.has(payload.sessionID)) return
+      turn(payload.sessionID)
+      set(payload.sessionID, payload.goal)
+    }),
+  )
+  onCleanup(input.on("server.connected", () => turns.forEach((_, sessionID) => load(sessionID))))
+  return {
+    get(sessionID: string) {
+      if (!turns.has(sessionID)) load(sessionID)
+      return goals[sessionID] ?? undefined
+    },
+  }
+}
diff --git a/packages/tui/src/feature-plugins/prompt/goal.tsx b/packages/tui/src/feature-plugins/prompt/goal.tsx
index ad5c0aa827ab..ee42d440eee6 100644
--- a/packages/tui/src/feature-plugins/prompt/goal.tsx
+++ b/packages/tui/src/feature-plugins/prompt/goal.tsx
@@ -1,59 +1,25 @@
 import type { Plugin } from "@opencode/plugin/tui"
-import { Goal } from "@opencode/schema/goal"
-import { createEffect, createMemo, createSignal, on, onCleanup, Show, type Accessor } from "solid-js"
+import type { SessionGoal } from "@opencode/plugin/tui/context"
+import { createMemo, createSignal, Show, type Accessor } from "solid-js"
 import { Keymap } from "../../context/keymap"
 import { useTheme } from "../../context/theme"
 import { DialogFooter, DialogHeader, DialogLayout, type DialogFooterAction } from "../../ui/dialog"
 
-/**
- * The goal `/goal` set on a Session, from the goal plugin's RPC: fetched when the Session changes or the server
- * reconnects, since changes published meanwhile were missed, and kept current from its `changed` events.
- */
+/** The goal `/goal` set on a Session, kept current by the host. */
 export function createGoal(context: Plugin.Context, sessionID: Accessor<string | undefined>) {
-  const [goal, setGoal] = createSignal<Goal.State>()
-  const rpc = context.client.rpc(Goal.Definition)
-  // A change that arrives while a fetch is in flight is newer than its reply, so each change or fetch takes a turn.
-  const turn = { value: 0 }
-  const load = (id: string) => {
-    const current = ++turn.value
-    const directory = context.data.session.get(id)?.location.directory
-    // A server without the goal plugin answers with an error, and the Session shows no goal.
-    void rpc.get({ sessionID: id }, directory ? { location: { directory } } : undefined).then(
-      (next) => {
-        if (current === turn.value && sessionID() === id) setGoal(next ?? undefined)
-      },
-      () => undefined,
-    )
-  }
-  onCleanup(
-    rpc.events.on("changed", (event) => {
-      if (event.data.sessionID !== sessionID()) return
-      turn.value++
-      setGoal(event.data.goal ?? undefined)
-    }),
-  )
-  onCleanup(
-    context.data.on("server.connected", () => {
-      const id = sessionID()
-      if (id) load(id)
-    }),
-  )
-  createEffect(
-    on(sessionID, (id) => {
-      setGoal(undefined)
-      if (id) load(id)
-    }),
-  )
-  return goal
+  return createMemo(() => {
+    const id = sessionID()
+    return id ? context.data.session.goal(id) : undefined
+  })
 }
 
-function goalColor(theme: Plugin.Context["theme"], goal: Goal.State) {
+function goalColor(theme: Plugin.Context["theme"], goal: SessionGoal) {
   if (goal.status === "paused") return theme.text.feedback.warning.base
   if (goal.status === "complete") return theme.text.feedback.success.base
   return theme.text.muted
 }
 
-function goalLabel(goal: Goal.State) {
+function goalLabel(goal: SessionGoal) {
   if (goal.status === "paused") return "goal paused"
   if (goal.status === "complete") return "goal met"
   return "goal"
@@ -66,10 +32,10 @@ function goalLabel(goal: Goal.State) {
 export function GoalStatus(props: {
   context: Plugin.Context
   sessionID: string
-  goal: Accessor<Goal.State | undefined>
+  goal: Accessor<SessionGoal | undefined>
 }) {
   const [hovered, setHovered] = createSignal(false)
-  const color = (current: Goal.State) =>
+  const color = (current: SessionGoal) =>
     hovered() ? props.context.theme.text.base : goalColor(props.context.theme, current)
 
   return (
@@ -91,7 +57,7 @@ export function GoalStatus(props: {
 }
 
 /** Opens the goal dialog for a Session, or explains how to start one. */
-function showGoal(context: Plugin.Context, sessionID: string, goal: Accessor<Goal.State | undefined>) {
+function showGoal(context: Plugin.Context, sessionID: string, goal: Accessor<SessionGoal | undefined>) {
   if (!goal()) {
     context.ui.toast.show({ message: "No goal is set. Start one with /goal <objective>.", variant: "info" })
     return
@@ -99,11 +65,7 @@ function showGoal(context: Plugin.Context, sessionID: string, goal: Accessor<Goa
   context.ui.dialog.show(() => <GoalDialog context={context} sessionID={sessionID} goal={goal} />)
 }
 
-function GoalDialog(props: {
-  context: Plugin.Context
-  sessionID: string
-  goal: Accessor<Goal.State | undefined>
-}) {
+function GoalDialog(props: { context: Plugin.Context; sessionID: string; goal: Accessor<SessionGoal | undefined> }) {
   const theme = useTheme().surface("dialog")
   const goal = props.goal
   const run = (text: "pause" | "resume" | "clear") => {
diff --git a/packages/tui/src/plugin/api.tsx b/packages/tui/src/plugin/api.tsx
index 35a4eac6e563..80956d32f3be 100644
--- a/packages/tui/src/plugin/api.tsx
+++ b/packages/tui/src/plugin/api.tsx
@@ -4,11 +4,13 @@ import type {
   Context,
   Dialog,
   DialogSelectOptions,
+  Layout,
   Page,
   SlotClaim,
   SlotMap,
   SlotPath,
   Toast,
+  ToolRender,
 } from "@opencode/plugin/tui/context"
 import type { Placement, PlacementKind } from "./structure"
 import { infoStringToFiletype, type MarkdownCodeBlockRenderer } from "@opentui/core"
@@ -32,6 +34,7 @@ import { useSessionTabs } from "../context/session-tabs"
 import { useOptionalPanel } from "../context/panel"
 import { useLocal } from "../context/local"
 import { abbreviateHome } from "../util/path-format"
+import { PluginMarkdown } from "./render"
 
 export type Dispose = () => Promise<void>
 
@@ -50,12 +53,16 @@ const placements = ["prepend", "append", "before", "after", "replace"] as const
 // The provider's registration store, narrowed to what a plugin context needs:
 // route/slot registration lands there, but ordering and lifecycle stay owned
 // by the provider.
+export type RegistryKind = "routes" | "slots" | "markdown" | "layout" | "tools"
+
 export type Registry = {
-  has(kind: "routes" | "slots" | "markdown", name: string): boolean
+  has(kind: RegistryKind, name: string): boolean
   set(kind: "routes", name: string, page: Page): void
   set(kind: "slots", name: string, claim: RegisteredSlot): void
   set(kind: "markdown", name: string, render: MarkdownCodeBlockRenderer): void
-  remove(kind: "routes" | "slots" | "markdown", name: string): void
+  set(kind: "layout", name: string, layout: Layout): void
+  set(kind: "tools", name: string, render: ToolRender): void
+  remove(kind: RegistryKind, name: string): void
   active(): boolean
 }
 
@@ -99,6 +106,7 @@ export function createPluginContext(input: {
   input.owned.push(async () => host.panel?.release(input.id))
   let context: Context
   let claims = 0
+  let layouts = 0
   // Every dialog and registered render is wrapped so plugin components can
   // reach their own context through usePlugin().
   const provide = (render: () => JSX.Element) => (
@@ -132,7 +140,7 @@ export function createPluginContext(input: {
   }
   // Unregistering after deactivation is a no-op: deactivate already resets
   // the registration's routes and slots wholesale.
-  const registration = (kind: "routes" | "slots" | "markdown", name: string) => {
+  const registration = (kind: RegistryKind, name: string) => {
     let registered = true
     const unregister = () => {
       if (!registered) return
@@ -310,6 +318,17 @@ export function createPluginContext(input: {
         })
         return registration("slots", key)
       },
+      layout(value: Layout) {
+        const key = `layout#${layouts++}`
+        input.registry.set("layout", key, value)
+        return registration("layout", key)
+      },
+      tool(name, render) {
+        if (input.registry.has("tools", name)) throw new Error(`Tool renderer already registered: ${name}`)
+        input.registry.set("tools", name, (toolInput) => provide(() => render(toolInput)))
+        return registration("tools", name)
+      },
+      Markdown: PluginMarkdown,
     },
   }
   return context
diff --git a/packages/tui/src/plugin/context.tsx b/packages/tui/src/plugin/context.tsx
index 7bcdb4ab4213..c7a2759da7a8 100644
--- a/packages/tui/src/plugin/context.tsx
+++ b/packages/tui/src/plugin/context.tsx
@@ -16,7 +16,7 @@ import {
 import path from "path"
 import { stat } from "fs/promises"
 import { fileURLToPath } from "url"
-import type { Page } from "@opencode/plugin/tui/context"
+import type { Layout, Page, ToolRender } from "@opencode/plugin/tui/context"
 import { Host } from "@opencode/plugin/host"
 import { resolveSlots, type Claim } from "./structure"
 import { createStore, produce, reconcile as reconcileStore, unwrap } from "solid-js/store"
@@ -27,7 +27,14 @@ import { useTuiLifecycle } from "../context/runtime"
 import { useClient } from "../context/client"
 import { useData } from "../context/data"
 import { errorMessage } from "../util/error"
-import { createPluginContext, usePluginHost, type Dispose, type RegisteredSlot, type SlotRender } from "./api"
+import {
+  createPluginContext,
+  usePluginHost,
+  type Dispose,
+  type RegisteredSlot,
+  type RegistryKind,
+  type SlotRender,
+} from "./api"
 import { createSourceWatcher } from "./watch"
 import { discoverPluginTargets, localSource, mergePluginTargets } from "./discovery"
 import { createPluginSources } from "./source"
@@ -62,6 +69,10 @@ type Value = {
     readonly resolved: () => ReturnType<typeof resolveSlots<SlotRender>>
   }
   readonly markdown: () => MarkdownOptions["renderNode"]
+  /** Layout knobs merged across active plugins; later-enabled plugins win per field. */
+  readonly layout: () => Layout
+  /** The renderer for one canonical tool name; the last-enabled active plugin that registered one wins. */
+  readonly tool: (name: string) => { readonly plugin: string; readonly render: ToolRender } | undefined
   readonly activate: (id: string) => Promise<boolean>
   readonly deactivate: (id: string) => Promise<boolean>
 }
@@ -76,6 +87,8 @@ type Registration = {
   routes: Record<string, Page>
   slots: Record<string, RegisteredSlot>
   markdown: Record<string, MarkdownCodeBlockRenderer>
+  layout: Record<string, Layout>
+  tools: Record<string, ToolRender>
   cleanups: Dispose[]
 }
 
@@ -145,7 +158,31 @@ export function PluginProvider(props: ParentProps<{ packages: PackageSource; dir
     setStore("registrations", id, "routes", reconcileStore({}))
     setStore("registrations", id, "slots", reconcileStore({}))
     setStore("registrations", id, "markdown", reconcileStore({}))
+    setStore("registrations", id, "layout", reconcileStore({}))
+    setStore("registrations", id, "tools", reconcileStore({}))
   }
+  // Registration-store key order is enable order, so later items win.
+  const layout = createMemo<Layout>(() =>
+    Object.values(store.registrations)
+      .flatMap((registration) => (registration.active ? Object.values(registration.layout) : []))
+      .reduce<Layout>(
+        (merged, item) => ({
+          ...merged,
+          ...item,
+          // Transcript defaults merge field by field, so two plugins may each set one.
+          transcript: item.transcript ? { ...merged.transcript, ...item.transcript } : merged.transcript,
+        }),
+        {},
+      ),
+  )
+  const tools = createMemo(() => {
+    const result = new Map<string, { plugin: string; render: ToolRender }>()
+    for (const [plugin, registration] of Object.entries(store.registrations)) {
+      if (!registration.active) continue
+      for (const [name, render] of Object.entries(registration.tools)) result.set(name, { plugin, render })
+    }
+    return result
+  })
 
   const activate = async (id: string) => {
     const item = store.registrations[id]
@@ -164,9 +201,9 @@ export function PluginProvider(props: ParentProps<{ packages: PackageSource; dir
       registry: {
         has: (kind, name) => Boolean(store.registrations[id]?.[kind][name]),
         set: (
-          kind: "routes" | "slots" | "markdown",
+          kind: RegistryKind,
           name: string,
-          value: Page | RegisteredSlot | MarkdownCodeBlockRenderer,
+          value: Page | RegisteredSlot | MarkdownCodeBlockRenderer | Layout | ToolRender,
         ) => setStore("registrations", id, kind, name, () => value),
         remove: (kind, name) =>
           setStore(
@@ -608,6 +645,8 @@ export function PluginProvider(props: ParentProps<{ packages: PackageSource; dir
         route: (id, name) => store.registrations[id]?.routes[name]?.render,
         slots: { register: registerSlot, resolved },
         markdown,
+        layout,
+        tool: (name) => tools().get(name),
         // Manual dialog toggles join the same chain as reconciles so a
         // toggle mid-reload cannot mix registrations across generations.
         activate: (id) => enqueue(() => activate(id)),
@@ -708,6 +747,8 @@ function toRegistration(item: Desired): Registration {
     routes: {},
     slots: {},
     markdown: {},
+    layout: {},
+    tools: {},
     cleanups: [],
   }
 }
diff --git a/packages/tui/src/plugin/render.tsx b/packages/tui/src/plugin/render.tsx
index e7e93ee032cb..76c8fb4ed239 100644
--- a/packages/tui/src/plugin/render.tsx
+++ b/packages/tui/src/plugin/render.tsx
@@ -14,10 +14,12 @@ import {
   type ParentProps,
 } from "solid-js"
 import { isShallowEqual } from "remeda"
-import type { SlotMap, SlotPath } from "@opencode/plugin/tui/context"
+import type { MarkdownProps, SlotMap, SlotPath } from "@opencode/plugin/tui/context"
 import type { SlotRender } from "./api"
 import { contains, emptySlotted, type Claim } from "./structure"
+import { useConfig } from "../config"
 import { useRoute } from "../context/route"
+import { useTheme, useThemes } from "../context/theme"
 import { useToast } from "../ui/toast"
 import { errorMessage } from "../util/error"
 import { usePlugin } from "./context"
@@ -156,3 +158,45 @@ export function Slot<Path extends SlotPath>(props: SlotProps<Path>) {
     </>
   )
 }
+
+// The renderer a plugin registered for one tool through ui.tool, contained
+// like a slot contribution; the host's own row when none did.
+export function PluginTool(props: ParentProps<{ readonly input: SlotMap["session.part.tool"] }>) {
+  const plugins = usePlugin()
+  const claim = createMemo(() => plugins.tool(props.input.tool))
+  return (
+    // Keyed so a hot reload or a new owner recreates the boundary.
+    <Show keyed when={claim()} fallback={props.children}>
+      {(item) => (
+        <PluginBoundary id={item.plugin} where={`tool ${props.input.tool}`}>
+          {createComponent(
+            item.render,
+            mergeProps(() => props.input),
+          )}
+        </PluginBoundary>
+      )}
+    </Show>
+  )
+}
+
+// ui.Markdown: the transcript's markdown, with the current syntax style,
+// every registered code-block renderer and the user's markdown mode.
+export function PluginMarkdown(props: MarkdownProps) {
+  const plugins = usePlugin()
+  const theme = useTheme()
+  const { currentSyntax: syntax } = useThemes()
+  const config = useConfig()
+  return (
+    <markdown
+      syntaxStyle={syntax()}
+      renderNode={plugins.markdown()}
+      content={props.content}
+      streaming={props.streaming ?? false}
+      internalBlockMode="top-level"
+      tableOptions={{ style: "grid", cellPaddingX: 1 }}
+      conceal={(config.data.session?.markdown ?? "rendered") === "rendered"}
+      fg={props.fg ?? theme.markdown.text}
+      bg={props.bg ?? theme.background.base}
+    />
+  )
+}
diff --git a/packages/tui/src/routes/session/index.tsx b/packages/tui/src/routes/session/index.tsx
index e470eae06ccc..b31c6e4e9f6f 100644
--- a/packages/tui/src/routes/session/index.tsx
+++ b/packages/tui/src/routes/session/index.tsx
@@ -100,8 +100,9 @@ import { collapseShellOutput, collapseToolOutput } from "../../util/collapse-too
 import { Keymap, type KeymapCommand } from "../../context/keymap"
 import { usePathFormatter } from "../../context/path-format"
 import { useLocation } from "../../context/location"
-import { Slot } from "../../plugin/render"
+import { PluginTool, Slot } from "../../plugin/render"
 import { usePlugin } from "../../plugin/context"
+import type { TranscriptRowKind } from "@opencode/plugin/tui/context"
 import {
   cacheReuseDrop,
   completeGroupBoundary,
@@ -147,6 +148,9 @@ const BACKGROUND_TOOL_HINT_DELAY = 3_000
 const TRANSCRIPT_TAIL_ROWS = 40
 const TRANSCRIPT_BACKFILL_CHUNK = 60
 
+/** The box holding the session.transcript.start slot, first in the transcript scroll. */
+const TRANSCRIPT_START = "session-transcript-start"
+
 export function Session(props: {
   scrollRef?: (scroll: ScrollBoxRenderable | undefined) => void
   verticalTabsWidth: number
@@ -159,6 +163,7 @@ export function Session(props: {
   width?: number
 }) {
   const epilogue = useEpilogue()
+  const plugins = usePlugin()
   const clipboard = useClipboard()
   const writeExport = async (file: string, content: string) => {
     await mkdir(path.dirname(file), { recursive: true })
@@ -240,11 +245,16 @@ export function Session(props: {
 
   const renderer = useRenderer()
   const dimensions = useTerminalDimensions()
-  const thinkingMode = createMemo<ThinkingMode>(() => config.session?.thinking ?? "hide")
+  // The user's choice wins over a plugin's transcript default.
+  const thinkingMode = createMemo<ThinkingMode>(
+    () => config.session?.thinking ?? plugins.layout().transcript?.thinking ?? "hide",
+  )
   const showScrollbar = createMemo(() => config.session?.scrollbar ?? false)
   const markdownMode = createMemo(() => config.session?.markdown ?? "rendered")
   const diffWrapMode = createMemo(() => config.diffs?.wrap ?? "word")
-  const groupExploration = createMemo(() => config.session?.grouping !== "none")
+  const groupExploration = createMemo(
+    () => (config.session?.grouping ?? plugins.layout().transcript?.grouping) !== "none",
+  )
   const verbosity = createMemo(() => config.session?.verbosity ?? defaultVerbosity)
   // High opens exploration and instruction summaries by default; everything else starts collapsed.
   const groupExpanded = (groupID: string, kind: GroupKind) =>
@@ -258,7 +268,9 @@ export function Session(props: {
     enabled: () => props.sidebarVisible && dimensions().width - props.verticalTabsWidth <= 120 && !disabled(),
     commands: [{ bind: "escape,ctrl+c", title: "Close sidebar", group: "Session", run: props.onToggleSidebar }],
   }))
-  const contentWidth = createMemo(() => (props.width ?? dimensions().width - props.verticalTabsWidth) - 4)
+  const contentWidth = createMemo(
+    () => (props.width ?? dimensions().width - props.verticalTabsWidth) - 2 * (plugins.layout().inset ?? 2),
+  )
   const models = createMemo(() => data.location.model.list(location()) ?? [])
 
   const scrollAcceleration = createMemo(() => getScrollAcceleration(config))
@@ -411,7 +423,10 @@ export function Session(props: {
   const pinAbove = () => {
     if (!scroll || scroll.isDestroyed) return
     if (scroll.stickyScroll && scroll.scrollTop >= scroll.scrollHeight - scroll.viewport.height) return
-    const node = scroll.getChildren().find((node) => node.height > 0 && node.y + node.height > scroll.viewport.y)
+    // The transcript-start slot stays on top while older rows load beneath it, so it never anchors.
+    const node = scroll
+      .getChildren()
+      .find((node) => node.id !== TRANSCRIPT_START && node.height > 0 && node.y + node.height > scroll.viewport.y)
     if (node) afterLayout(scroll.anchor(node))
   }
 
@@ -1516,10 +1531,14 @@ export function Session(props: {
           flexGrow={1}
           minHeight={0}
           paddingBottom={1}
-          paddingLeft={dimensions().width < 44 ? 1 : 2}
-          paddingRight={dimensions().width < 44 ? 1 : 2}
+          paddingLeft={plugins.layout().inset ?? (dimensions().width < 44 ? 1 : 2)}
+          paddingRight={plugins.layout().inset ?? (dimensions().width < 44 ? 1 : 2)}
         >
           <Show when={session()}>
+            {/* Keeps its full height; the transcript below takes what is left. */}
+            <box flexShrink={0}>
+              <Slot path="session.header" input={{ sessionID: route.sessionID }} />
+            </box>
             <box flexGrow={1} minHeight={0} position="relative">
               <scrollbox
                 ref={(r) => {
@@ -1549,10 +1568,15 @@ export function Session(props: {
                   updateAwayFromBottom()
                 }}
               >
+                {/* Pinned above every row, so the history scroll anchor skips it (pinAbove). */}
+                <box id={TRANSCRIPT_START} flexShrink={0}>
+                  <Slot path="session.transcript.start" input={{ sessionID: route.sessionID }} />
+                </box>
                 <For each={visibleRows()}>
                   {(row, index) => (
                     <SessionRowView
                       row={row}
+                      previous={visibleRows()[index() - 1]}
                       message={(messageID) => data.session.message.get(route.sessionID, messageID)}
                       boundaryID={boundaries()[index() + hidden()]}
                     />
@@ -1669,18 +1693,44 @@ export function Session(props: {
 
 type SessionRowViewProps = {
   row: SessionRow
+  previous?: SessionRow
   message: (messageID: string) => SessionMessageInfo | undefined
   boundaryID?: string
 }
 
+// The coarse row kind a plugin layout rule sees: one name per visual role.
+function transcriptRowKind(
+  row: SessionRow,
+  message: (messageID: string) => SessionMessageInfo | undefined,
+): TranscriptRowKind {
+  if (row.type === "group") return "group"
+  if (row.type === "assistant-footer") return "footer"
+  if (row.type === "message") return message(row.messageID)?.type === "user" ? "user" : "other"
+  if (row.type !== "part") return "other"
+  const item = message(row.ref.messageID)
+  if (item?.type !== "assistant") return "other"
+  const part = resolvePart(item, row.ref.partID)
+  if (part?.type === "text" || part?.type === "reasoning" || part?.type === "tool") return part.type
+  return "other"
+}
+
 function SessionRowView(props: SessionRowViewProps) {
+  const plugins = usePlugin()
   const [target, setTarget] = createSignal<BoxRenderable>()
   useEntryAnchor({
     entry: () => (props.row.type === "group" ? undefined : props.row),
     node: target,
   })
+  const gap = createMemo(() => {
+    const rule = plugins.layout().rowGap
+    if (!rule) return 1
+    return rule({
+      kind: transcriptRowKind(props.row, props.message),
+      previous: props.previous ? transcriptRowKind(props.previous, props.message) : undefined,
+    })
+  })
   return (
-    <box ref={setTarget} id={sessionRowID(props.row, props.boundaryID)} marginTop={1} flexShrink={0}>
+    <box ref={setTarget} id={sessionRowID(props.row, props.boundaryID)} marginTop={gap()} flexShrink={0}>
       <Switch>
         <Match when={props.row.type === "group" ? props.row : undefined}>
           {(row) => (
@@ -1701,6 +1751,7 @@ function SessionRowView(props: SessionRowViewProps) {
 }
 
 function SessionEntryView(props: { row: SessionEntry; message: SessionRowViewProps["message"]; images?: boolean }) {
+  const ctx = use()
   return (
     <Switch>
       <Match when={props.row.type === "message" ? props.row : undefined}>
@@ -1719,7 +1770,12 @@ function SessionEntryView(props: { row: SessionEntry; message: SessionRowViewPro
           <Show when={props.message(row().messageID)}>
             {(message) => (
               <Show when={message().type === "assistant"}>
-                <AssistantFooter message={message() as SessionMessageAssistant} />
+                <Slot
+                  path="session.message.assistant.footer"
+                  input={{ sessionID: ctx.sessionID, messageID: message().id }}
+                >
+                  <AssistantFooter message={message() as SessionMessageAssistant} />
+                </Slot>
               </Show>
             )}
           </Show>
@@ -1929,10 +1985,13 @@ function BackgroundToolHint(props: { messages: SessionMessageInfo[] }) {
 }
 
 function SessionMessageView(props: { message: SessionMessageInfo }) {
+  const ctx = use()
   return (
     <Switch>
       <Match when={props.message.type === "user"}>
-        <UserMessage message={props.message as SessionMessageUser} />
+        <Slot path="session.message.user" input={{ sessionID: ctx.sessionID, messageID: props.message.id }}>
+          <UserMessage message={props.message as SessionMessageUser} />
+        </Slot>
       </Match>
       <Match when={props.message.type === "shell"}>
         <ShellMessage message={props.message as Extract<SessionMessageInfo, { type: "shell" }>} />
@@ -1983,26 +2042,40 @@ function SessionPartView(props: {
     if (item?.type !== "assistant") return
     return resolvePart(item, props.partRef.partID)
   })
+  const ctx = use()
+  const input = () => ({ sessionID: ctx.sessionID, messageID: props.partRef.messageID, partID: props.partRef.partID })
+  const toolInput = () => {
+    const item = part()
+    return { ...input(), tool: item?.type === "tool" ? canonicalToolName(item.name) : "" }
+  }
   return (
     <Show when={part()}>
       {(item) => (
         <Switch>
           <Match when={item().type === "text"}>
-            <TextPart
-              part={item() as SessionMessageAssistantText}
-              message={message() as SessionMessageAssistant}
-              last={false}
-            />
+            <Slot path="session.part.text" input={input()}>
+              <TextPart
+                part={item() as SessionMessageAssistantText}
+                message={message() as SessionMessageAssistant}
+                last={false}
+              />
+            </Slot>
           </Match>
           <Match when={item().type === "reasoning"}>
-            <ReasoningPart
-              part={item() as SessionMessageAssistantReasoning}
-              message={message() as SessionMessageAssistant}
-              last={false}
-            />
+            <Slot path="session.part.reasoning" input={input()}>
+              <ReasoningPart
+                part={item() as SessionMessageAssistantReasoning}
+                message={message() as SessionMessageAssistant}
+                last={false}
+              />
+            </Slot>
           </Match>
           <Match when={item().type === "tool"}>
-            <ToolPart part={item() as SessionMessageAssistantTool} images={props.images} />
+            <Slot path="session.part.tool" input={toolInput()}>
+              <PluginTool input={toolInput()}>
+                <ToolPart part={item() as SessionMessageAssistantTool} images={props.images} />
+              </PluginTool>
+            </Slot>
           </Match>
         </Switch>
       )}
diff --git a/packages/tui/src/routes/session/rows.ts b/packages/tui/src/routes/session/rows.ts
index ed966402fc45..3e1dca6a1d8f 100644
--- a/packages/tui/src/routes/session/rows.ts
+++ b/packages/tui/src/routes/session/rows.ts
@@ -483,11 +483,4 @@ function rowBoundaryMessageID(row: SessionRow, messages: Map<string, SessionMess
   if (message?.type === "assistant") return message.id
 }
 
-export function resolvePart(message: SessionMessageAssistant, partID: string) {
-  const tool = message.content.find((part) => part.type === "tool" && part.id === partID)
-  if (tool) return tool
-  const match = /^(text|reasoning):(\d+)$/.exec(partID)
-  if (!match) return
-  const ordinal = Number(match[2])
-  return message.content.filter((part) => part.type === match[1])[ordinal]
-}
+export { resolvePart } from "../../util/session"
diff --git a/packages/tui/src/util/session.ts b/packages/tui/src/util/session.ts
index c7213e2205ed..47ccd07ec928 100644
--- a/packages/tui/src/util/session.ts
+++ b/packages/tui/src/util/session.ts
@@ -1,4 +1,4 @@
-import type { ModelInfo, SessionMessageInfo } from "@opencode/client"
+import type { ModelInfo, SessionMessageAssistant, SessionMessageInfo } from "@opencode/client"
 import { lastAssistantWithUsage } from "@opencode/client/solid"
 import { Locale } from "./locale"
 
@@ -56,10 +56,21 @@ export function contextUsage(
   const model = models?.find((model) => model.providerID === last.model.providerID && model.id === last.model.id)
   return {
     tokens,
+    limit: model?.limit.context || undefined,
     percent: model?.limit.context ? Math.round((tokens / model.limit.context) * 100) : undefined,
   }
 }
 
+/** One part of an assistant message: a tool call by its call ID, text and reasoning by ordinal (`text:2`). */
+export function resolvePart(message: SessionMessageAssistant, partID: string) {
+  const tool = message.content.find((part) => part.type === "tool" && part.id === partID)
+  if (tool) return tool
+  const match = /^(text|reasoning):(\d+)$/.exec(partID)
+  if (!match) return
+  const ordinal = Number(match[2])
+  return message.content.filter((part) => part.type === match[1])[ordinal]
+}
+
 export function formatContextUsage(tokens: number, percent?: number) {
   const value = Locale.number(tokens)
   return percent === undefined ? value : `${value} (${percent}%)`
diff --git a/packages/tui/test/feature-plugins/prompt-footer.test.tsx b/packages/tui/test/feature-plugins/prompt-footer.test.tsx
index f651f3070181..bd5281422d06 100644
--- a/packages/tui/test/feature-plugins/prompt-footer.test.tsx
+++ b/packages/tui/test/feature-plugins/prompt-footer.test.tsx
@@ -23,10 +23,10 @@ test("prompt footer separates simultaneous subagent, shell, and usage status", a
         id === "session.child.first" ? ["ctrl+j"] : id === "command.palette.show" ? ["ctrl+p"] : [],
       dispatch: (id: string) => dispatched.push(id),
     },
-    client: { rpc: () => ({ get: () => Promise.resolve(null), events: { on: () => () => {} } }) },
     data: {
       on: () => () => {},
       session: {
+        goal: () => undefined,
         family: () => ["session", "child"],
         status: (id: string) => (id === "child" ? "running" : "idle"),
         get: () => ({ id: "session", location: { directory: "/workspace" } }),
@@ -83,10 +83,10 @@ test("prompt footer can hide details", async () => {
         return []
       },
     },
-    client: { rpc: () => ({ get: () => Promise.resolve(null), events: { on: () => () => {} } }) },
     data: {
       on: () => () => {},
       session: {
+        goal: () => undefined,
         family: () => ["session"],
         status: () => "running",
         get: () => ({ id: "session", location: { directory: "/workspace" } }),
@@ -145,17 +145,9 @@ test("prompt footer can hide details", async () => {
 test("prompt footer shows the session's goal without its objective and opens it on click", async () => {
   const muted = RGBA.fromInts(100, 100, 100)
   const warning = RGBA.fromInts(200, 200, 0)
-  const goal = {
-    id: "goal",
-    objective: "Make the test suite pass",
-    status: "active",
-    rounds: 3,
-    maxRounds: 50,
-    boot: "boot",
-    updatedAt: 0,
-  }
-  const fetched = Promise.resolve(goal)
-  const changed: ((event: { data: { sessionID: string; goal: unknown } }) => void)[] = []
+  const goal = { objective: "Make the test suite pass", status: "active" as const }
+  // The host keeps each Session's goal current; the footer only reads it.
+  const [goals, setGoals] = createSignal<Record<string, unknown>>({ session: goal })
   const dialogs: unknown[] = []
   const context = {
     location: { directory: "/workspace" },
@@ -168,15 +160,10 @@ test("prompt footer shows the session's goal without its objective and opens it
     },
     keymap: { shortcuts: () => [] },
     ui: { dialog: { show: (render: unknown) => dialogs.push(render) }, toast: { show: () => {} } },
-    client: {
-      rpc: () => ({
-        get: () => fetched,
-        events: { on: (_name: string, handler: (typeof changed)[number]) => (changed.push(handler), () => {}) },
-      }),
-    },
     data: {
       on: () => () => {},
       session: {
+        goal: (sessionID: string) => goals()[sessionID],
         family: () => ["session"],
         status: () => "idle",
         get: () => ({ id: "session", location: { directory: "/workspace" } }),
@@ -193,8 +180,6 @@ test("prompt footer shows the session's goal without its objective and opens it
   )
 
   try {
-    // The footer fetches the goal from the goal plugin's RPC.
-    await fetched
     await app.renderOnce()
     const frame = app.captureCharFrame()
     expect(frame).toContain("◎ goal")
@@ -207,16 +192,15 @@ test("prompt footer shows the session's goal without its objective and opens it
     expect(dialogs).toHaveLength(1)
     await app.mockMouse.moveTo(70, 1)
 
-    // Then it follows the plugin's changes for this Session only.
-    const change = (sessionID: string, next: unknown) =>
-      changed.forEach((handler) => handler({ data: { sessionID, goal: next } }))
+    // Then it follows the goal of this Session only.
+    const change = (sessionID: string, next: unknown) => setGoals((all) => ({ ...all, [sessionID]: next }))
     change("session", { ...goal, status: "paused", reason: "Stopped by the user" })
-    change("other", null)
+    change("other", undefined)
     await app.renderOnce()
     expect(app.captureCharFrame()).toContain("◎ goal paused")
     expect(findText(app.renderer.root, "◎ goal paused")?.fg.toInts()).toEqual(warning.toInts())
 
-    change("session", null)
+    change("session", undefined)
     await app.renderOnce()
     expect(app.captureCharFrame()).not.toContain("goal")
   } finally {
diff --git a/packages/tui/test/fixture/plugin/session-reads/tui.tsx b/packages/tui/test/fixture/plugin/session-reads/tui.tsx
new file mode 100644
index 000000000000..9afc3eb6426b
--- /dev/null
+++ b/packages/tui/test/fixture/plugin/session-reads/tui.tsx
@@ -0,0 +1,42 @@
+import { Plugin } from "@opencode/plugin/tui"
+import { TextRenderable } from "@opentui/core"
+
+// Reads a session through data.session.usage, data.session.goal and
+// data.session.part.get, and renders a text part with ui.Markdown.
+export default Plugin.define({
+  id: "fixture.session-reads",
+  setup(context) {
+    context.markdown.registerCodeBlockRenderer(
+      "probe",
+      () => new TextRenderable(context.renderer, { content: "Probe fence rendered", height: 1 }),
+    )
+    context.ui.slot({
+      append: "session.header",
+      render: (input) => {
+        const usage = () => context.data.session.usage(input.sessionID)
+        const goal = () => context.data.session.goal(input.sessionID)
+        return (
+          <box flexDirection="column">
+            <text>
+              usage {usage()?.tokens ?? "none"} of {usage()?.limit ?? "none"} ({usage()?.percent ?? "none"}%)
+            </text>
+            <text>
+              goal {goal()?.objective ?? "none"} [{goal()?.status ?? "none"}]
+            </text>
+          </box>
+        )
+      },
+    })
+    context.ui.slot({
+      replace: "session.part.text",
+      render: (input) => {
+        const part = () => context.data.session.part.get(input.sessionID, input.messageID, input.partID)
+        const content = () => {
+          const item = part()
+          return item?.type === "text" ? `Read ${input.partID}: ${item.text}` : ""
+        }
+        return <context.ui.Markdown content={content()} />
+      },
+    })
+  },
+})
diff --git a/packages/tui/test/fixture/plugin/tool-renderer/tui.tsx b/packages/tui/test/fixture/plugin/tool-renderer/tui.tsx
new file mode 100644
index 000000000000..0efedcf150c0
--- /dev/null
+++ b/packages/tui/test/fixture/plugin/tool-renderer/tui.tsx
@@ -0,0 +1,23 @@
+import { Plugin } from "@opencode/plugin/tui"
+
+// Renders every shell call itself and asks for an ungrouped transcript with
+// reasoning shown.
+export default Plugin.define({
+  id: "fixture.tool-renderer",
+  setup(context) {
+    context.ui.layout({ transcript: { grouping: "none", thinking: "show" } })
+    context.ui.tool("shell", (input) => {
+      const part = () => context.data.session.part.get(input.sessionID, input.messageID, input.partID)
+      const command = () => {
+        const item = part()
+        if (item?.type !== "tool" || typeof item.state.input === "string") return ""
+        return String((item.state.input as { command?: unknown }).command ?? "")
+      }
+      return (
+        <text>
+          Custom {input.tool} row: {command()}
+        </text>
+      )
+    })
+  },
+})
diff --git a/packages/tui/test/fixture/plugin/transcript-chrome/tui.tsx b/packages/tui/test/fixture/plugin/transcript-chrome/tui.tsx
new file mode 100644
index 000000000000..64c7d411dc25
--- /dev/null
+++ b/packages/tui/test/fixture/plugin/transcript-chrome/tui.tsx
@@ -0,0 +1,30 @@
+import { Plugin } from "@opencode/plugin/tui"
+
+// Claims the transcript's chrome: a header, a first row, the user prompt and
+// the turn footer, with tight rows, a one-cell inset and a band composer.
+export default Plugin.define({
+  id: "fixture.transcript-chrome",
+  setup(context) {
+    context.ui.layout({
+      inset: 1,
+      rowGap: (row) => (row.kind === "footer" ? 0 : 1),
+      composer: { chrome: "band", prefix: "> " },
+    })
+    context.ui.slot({ append: "session.header", render: () => <text>Header claimed</text> })
+    context.ui.slot({ append: "session.transcript.start", render: () => <text>Transcript start claimed</text> })
+    context.ui.slot({
+      replace: "session.message.user",
+      render: (input) => {
+        const text = () => {
+          const message = context.data.session.message.get(input.sessionID, input.messageID)
+          return message?.type === "user" ? message.text : ""
+        }
+        return <text>User band: {text()}</text>
+      },
+    })
+    context.ui.slot({
+      replace: "session.message.assistant.footer",
+      render: (input) => <text>Footer for {input.messageID}</text>,
+    })
+  },
+})
diff --git a/packages/tui/test/plugin-session-hooks.test.tsx b/packages/tui/test/plugin-session-hooks.test.tsx
new file mode 100644
index 000000000000..67d0b934793d
--- /dev/null
+++ b/packages/tui/test/plugin-session-hooks.test.tsx
@@ -0,0 +1,186 @@
+import { expect, test } from "bun:test"
+import { createAppFixture } from "./fixture/app"
+import { copyPlugin } from "./fixture/fixture"
+import { waitForHighlightedFrame } from "./fixture/frame"
+import { directory, json } from "./fixture/tui-client"
+
+const session = {
+  id: "ses_plugin_hooks",
+  title: "Plugin hooks",
+  projectID: "proj_test",
+  location: { directory },
+  cost: 0,
+  tokens: { input: 0, output: 0, reasoning: 0, cache: { read: 0, write: 0 } },
+  time: { created: 0, updated: 0 },
+}
+const model = { providerID: "fixture", id: "fixture" }
+// Newest first, as the server pages them.
+const messages = [
+  {
+    type: "assistant",
+    id: "msg_reply",
+    agent: "build",
+    model,
+    finish: "stop",
+    time: { created: 2, completed: 3 },
+    // 2,000 tokens of a 8,000-token window.
+    tokens: { input: 1000, output: 200, reasoning: 0, cache: { read: 800, write: 0 } },
+    content: [
+      { type: "reasoning", text: "Weighing the parser fix", time: { created: 2, completed: 2 } },
+      {
+        type: "tool",
+        id: "call_shell",
+        name: "bash",
+        time: { created: 2, completed: 3 },
+        state: {
+          status: "completed",
+          input: { command: "bun test parser" },
+          content: [{ type: "text", text: "1 pass" }],
+          metadata: {},
+        },
+      },
+      { type: "text", text: "The **parser** is fixed.\n\n```probe\nanything\n```" },
+    ],
+  },
+  { type: "user", id: "msg_ask", text: "Fix the parser", time: { created: 1 } },
+]
+const goal = {
+  id: "goal",
+  objective: "Ship the parser",
+  status: "active",
+  rounds: 1,
+  maxRounds: 50,
+  boot: "boot",
+  updatedAt: 0,
+}
+
+async function openSession(plugin: string) {
+  const fixture = await copyPlugin(plugin)
+  const setup = await createAppFixture({
+    width: 100,
+    height: 30,
+    config: { animations: false, tabs: { enabled: false }, plugins: [fixture.directory] },
+    args: { sessionID: session.id },
+    fetch: (url) => {
+      if (url.pathname === "/api/session") return json({ data: [session], cursor: {} })
+      if (url.pathname === `/api/session/${session.id}`) return json({ data: session })
+      if (url.pathname === `/api/session/${session.id}/message`) return json({ data: messages, cursor: {} })
+      if (/^\/api\/session\/[^/]+\/(inbox|permission)$/.test(url.pathname)) return json({ data: [] })
+      if (url.pathname === "/api/model")
+        return json({
+          location: { directory, project: { id: "proj_test", directory, canonical: directory } },
+          data: [{ ...model, name: "Fixture", variants: [], limit: { context: 8000, output: 1000 } }],
+        })
+      if (url.pathname === "/api/rpc/opencode.goal/get") return json({ output: goal })
+      return undefined
+    },
+  })
+  const dispose = setup[Symbol.asyncDispose]
+  return Object.assign(setup, {
+    async [Symbol.asyncDispose]() {
+      await dispose()
+      await fixture[Symbol.asyncDispose]()
+    },
+  })
+}
+
+test("a plugin reads a session's context usage, goal and parts, and renders host markdown", async () => {
+  await using app = await openSession("session-reads")
+  await app.ready
+  // part.get resolves text parts by ordinal; ui.Markdown conceals the markup and runs registered fence renderers.
+  const frame = await waitForHighlightedFrame(
+    app,
+    (frame) =>
+      frame.includes("usage 2000 of 8000 (25%)") &&
+      frame.includes("goal Ship the parser [active]") &&
+      frame.includes("Read text:0: The parser is fixed.") &&
+      frame.includes("Probe fence rendered"),
+  )
+  expect(frame).not.toContain("**parser**")
+  expect(frame).not.toContain("```")
+
+  // The goal follows the goal plugin's changes.
+  app.events.emit({
+    id: "evt_goal_changed",
+    created: 4,
+    type: "rpc.opencode.goal.changed",
+    location: { directory },
+    data: { sessionID: session.id, goal: { ...goal, status: "paused" } },
+  })
+  await app.waitForFrame((frame) => frame.includes("goal Ship the parser [paused]"))
+  app.events.emit({
+    id: "evt_goal_cleared",
+    created: 5,
+    type: "rpc.opencode.goal.changed",
+    location: { directory },
+    data: { sessionID: session.id, goal: null },
+  })
+  await app.waitForFrame((frame) => frame.includes("goal none [none]"))
+})
+
+test("a plugin renders one tool by canonical name and sets transcript defaults", async () => {
+  await using app = await openSession("tool-renderer")
+  await app.ready
+  // `bash` is the shell tool's canonical name; grouping "none" keeps the call its own row.
+  // thinking "show" expands reasoning the host hides by default.
+  await waitForHighlightedFrame(
+    app,
+    (frame) =>
+      frame.includes("Custom shell row: bun test parser") &&
+      frame.includes("Weighing the parser fix") &&
+      frame.includes("The parser is fixed."),
+  )
+})
+
+test("the user's transcript config wins over a plugin's defaults", async () => {
+  const fixture = await copyPlugin("tool-renderer")
+  try {
+    await using app = await createAppFixture({
+      width: 100,
+      height: 30,
+      config: {
+        animations: false,
+        tabs: { enabled: false },
+        plugins: [fixture.directory],
+        session: { thinking: "hide" },
+      },
+      args: { sessionID: session.id },
+      fetch: (url) => {
+        if (url.pathname === "/api/session") return json({ data: [session], cursor: {} })
+        if (url.pathname === `/api/session/${session.id}`) return json({ data: session })
+        if (url.pathname === `/api/session/${session.id}/message`) return json({ data: messages, cursor: {} })
+        if (/^\/api\/session\/[^/]+\/(inbox|permission)$/.test(url.pathname)) return json({ data: [] })
+        return undefined
+      },
+    })
+    await app.ready
+    const frame = await app.waitForFrame((frame) => frame.includes("Custom shell row: bun test parser"))
+    expect(frame).not.toContain("Weighing the parser fix")
+  } finally {
+    await fixture[Symbol.asyncDispose]()
+  }
+})
+
+test("a plugin claims the transcript's header, first row, user prompt and turn footer", async () => {
+  await using app = await openSession("transcript-chrome")
+  await app.ready
+  const frame = await waitForHighlightedFrame(
+    app,
+    (frame) =>
+      frame.includes("Header claimed") &&
+      frame.includes("Transcript start claimed") &&
+      frame.includes("User band: Fix the parser") &&
+      frame.includes("The parser is fixed.") &&
+      frame.includes("Footer for msg_reply"),
+  )
+  const lines = frame.split("\n")
+  // inset 1 starts rows one cell in.
+  expect(lines.find((line) => line.includes("User band"))).toStartWith(" User band")
+  // rowGap 0 for the footer puts it straight under the reply; every other row keeps one blank row above it.
+  const footer = lines.findIndex((line) => line.includes("Footer for msg_reply"))
+  expect(lines[footer - 1]).toContain("anything")
+  const user = lines.findIndex((line) => line.includes("User band"))
+  expect(lines[user - 1]?.trim()).toBe("")
+  // The band composer puts its prefix before the editor. Its bar is still drawn, in the band's colour.
+  expect(lines.some((line) => line.startsWith(" ┃> "))).toBe(true)
+})