diff --git a/apps/ui/src/App.tsx b/apps/ui/src/App.tsx
index 6a3a4c14..524fd8ae 100644
--- a/apps/ui/src/App.tsx
+++ b/apps/ui/src/App.tsx
@@ -29,7 +29,7 @@ import { shortcutForAria } from "./keyboard/keymap";
 
 // The Compass ADE shell — an Orca-inspired layout over the compass.v1 surface
 // (docs/specs/product/compass.md). A CSS grid: a topbar, a left agent-folder
-// tree, a central Bridge (swimlane board) / agent (ACP + terminals) view, a
+// tree, a central Bridge (swimlane board) / agent (session + terminals) view, a
 // right sidebar (fleet conversations + files/VCS/PR), and a bottom usage bar.
 // The board is primary; the "channel" and "agent" surfaces render as center
 // matches within the same shell (single Switch), reached via the store.
@@ -37,7 +37,7 @@ import { shortcutForAria } from "./keyboard/keymap";
 // This is the dev walking-skeleton made fully explorable: every surface reads
 // the in-memory stub (stub-data.ts) through one store (store.ts), so it renders
 // and is clickable in `vite dev` with no daemon and no Wails IPC. When the
-// daemon grows the real board / agent / ACP / audit streams, the store's
+// daemon grows the real board / agent / session / audit streams, the store's
 // accessors swap the fixture for the generated @compass/client and the
 // components stay as-is.
 
diff --git a/apps/ui/src/agent-state.ts b/apps/ui/src/agent-state.ts
index 36f78886..27829473 100644
--- a/apps/ui/src/agent-state.ts
+++ b/apps/ui/src/agent-state.ts
@@ -12,8 +12,8 @@ import type { AgentState } from "./stub-data";
  * set, the projection falls back to the pure enum mapping.
  */
 export interface AgentStreamRefinement {
-	/** An ACP permission / `ask` request is open on the stream — the agent has
-	 *  asked for input. Refines `WORKING` → `waiting` (Matt's "ask tool" state). */
+	/** An agent permission / `ask` request is open on the stream — the agent has
+	 *  asked for input. Refines `WORKING` → `waiting`. */
 	awaitingInput?: boolean;
 	/** The agent completed a turn and no human has opened its view yet. Refines
 	 *  `READY` → `done` (emerald check, deliberately not idle grey). */
diff --git a/apps/ui/src/app.css b/apps/ui/src/app.css
index 6a887d2e..df580a03 100644
--- a/apps/ui/src/app.css
+++ b/apps/ui/src/app.css
@@ -1,6 +1,6 @@
 /* Compass ADE — dev UI styling. Dark, dense, board-first. An Orca-inspired
  * shell: a left folder tree of agents, a central Bridge (swimlane board) or
- * agent (ACP + terminals) view, and a right sidebar carrying the fleet
+ * agent (session + terminals) view, and a right sidebar carrying the fleet
  * conversations (Supervisor · Status) above the issue files/VCS/PR
  * tabs, plus a bottom usage bar. All read one store. */
 
@@ -761,7 +761,7 @@
 	color: var(--cx-error);
 }
 
-/* ── Agent view: ACP conversation + terminals ──────────────────────────── */
+/* ── Agent view: session conversation + terminals ───────────────────────── */
 
 .agent-view {
 	display: grid;
@@ -915,8 +915,8 @@
 	padding: 1px 4px;
 }
 
-/* ACP conversation column. */
-.acp {
+/* Session conversation column. */
+.session {
 	display: flex;
 	flex-direction: column;
 	min-height: 0;
@@ -924,7 +924,7 @@
 	overflow: hidden;
 }
 
-.acp-stream {
+.session-stream {
 	flex: 1;
 	overflow-y: auto;
 	padding: 14px;
@@ -1283,7 +1283,7 @@
 }
 
 /* The prompt composer (non-functional in the mockup). */
-.acp-composer {
+.session-composer {
 	flex: none;
 	border-top: 1px solid var(--cx-border);
 	padding: 10px 12px;
@@ -1292,7 +1292,7 @@
 	align-items: flex-end;
 }
 
-.acp-composer .field {
+.session-composer .field {
 	flex: 1;
 	background: var(--cx-bg-panel);
 	border: 1px solid var(--cx-border);
@@ -1302,7 +1302,7 @@
 	font-size: 12px;
 }
 
-.acp-composer .send {
+.session-composer .send {
 	background: var(--cx-accent);
 	border: none;
 	border-radius: var(--cx-radius-sm);
@@ -2362,14 +2362,14 @@
 
 /* Fleet panes host a full-height flex conversation, not a scrolling document —
  * the counterpart of .r-pane { overflow-y: auto }. The border-right suppression
- * mirrors the dock's own .acp override against .acp's base border
+ * mirrors the dock's own session override against the session base border
  * (dock-in-sidebar D3/T1). */
 .r-pane.fleet {
 	display: flex;
 	overflow: hidden;
 }
 
-.r-pane.fleet .acp {
+.r-pane.fleet .session {
 	flex: 1;
 	min-height: 0;
 	border-right: none;
@@ -2716,7 +2716,7 @@
 	overflow: hidden;
 }
 
-.av-pane-body .acp {
+.av-pane-body .session {
 	flex: 1;
 	min-height: 0;
 	border-right: none;
@@ -3246,8 +3246,8 @@
 	font-size: 11px;
 }
 
-/* Conversation messages reuse the .msg family from the ACP view (role coloring,
- * head layout). Channel-specific bits below. */
+/* Conversation messages reuse the .msg family from the agent view (role
+ * coloring, head layout). Channel-specific bits below. */
 .msg-text {
 	white-space: pre-wrap;
 	overflow-wrap: anywhere;
diff --git a/apps/ui/src/comms-stub.ts b/apps/ui/src/comms-stub.ts
index 42e8415b..0f389984 100644
--- a/apps/ui/src/comms-stub.ts
+++ b/apps/ui/src/comms-stub.ts
@@ -35,8 +35,8 @@ export interface ChannelGroup {
 }
 
 /** A channel's kind (comms.proto ChannelKind). A plain channel is the default;
- *  DMs are direct conversations. An agent's ACP surface is NOT a channel — it is
- *  the agent workspace (the session observation panel), a separate surface. */
+ * DMs are direct conversations. An agent's session observation surface is not a
+ * channel — it is a separate workspace panel. */
 export type ChannelKind = "channel" | "dm" | "group_dm";
 
 /** Per-channel membership state — the still-in-design join/subscribe model
@@ -197,8 +197,8 @@ export function isQuestionAnswered(q: AskQuestion): boolean {
 /** A durable content block inside a channel message. The comms model
  *  narrows the proto's MessageBlock oneof to the two durable conversation kinds:
  *  `text` (settled markdown, may carry @-mentions) and `ask` (an inline async
- *  question). The rich ACP blocks (thought/tool_call/plan/diff) are NOT part of
- *  the conversation — they render in the session observation panel. */
+ *  question). Rich execution blocks (thought/tool_call/plan/diff) are not part
+ *  of the conversation — they render in the session observation panel. */
 export type ConvBlock =
 	| { kind: "text"; text: string }
 	| { kind: "ask"; ask: Ask };
diff --git a/apps/ui/src/live/adapt.ts b/apps/ui/src/live/adapt.ts
index 05d79985..572b748a 100644
--- a/apps/ui/src/live/adapt.ts
+++ b/apps/ui/src/live/adapt.ts
@@ -263,11 +263,11 @@ export function adaptAsk(w: WireAsk): Ask {
 
 /** Map a wire MessageBlock's oneof to a durable domain block, or `undefined` for
  *  any other/unset case. The domain narrows the proto oneof to the two DURABLE
- *  conversation kinds (comms-stub.ts:143-147): the rich ACP blocks
- *  (thought/tool_call/plan/diff) are execution trace that renders in the session
- *  observation panel, not the conversation, so a non-durable case is DROPPED —
- *  not mapped to a placeholder (which would render as a phantom message body)
- *  and not thrown on (which would blank the whole channel over one block). */
+ *  conversation kinds (`ConvBlock` in comms-stub.ts): rich execution blocks
+ *  (thought/tool_call/plan/diff) are session trace rendered in the observation
+ *  panel, not conversation content, so a non-durable case is DROPPED — not
+ *  mapped to a placeholder (which would render a phantom message body) and not
+ *  thrown on (which would blank the whole channel over one block). */
 function adaptBlock(w: WireMessage["blocks"][number]): ConvBlock | undefined {
 	switch (w.block.case) {
 		case "text":
diff --git a/go/gen/compass/v1/comms.pb.go b/go/gen/compass/v1/comms.pb.go
index f0a4d2df..8d7be74d 100644
--- a/go/gen/compass/v1/comms.pb.go
+++ b/go/gen/compass/v1/comms.pb.go
@@ -3,12 +3,12 @@
 // agents are first-class accounts in a management hierarchy. Channels nest in
 // channel groups, so a user's space (e.g. group "matt" → channel
 // "coordination", the path "matt.coordination") carries group-level
-// permissions. An agent's interactive surface — its ACP UI: the conversation
-// (text and structured asks) plus terminal and file panes — renders in the
-// agent's channel; the AgentWorkspace is the observation pane over that session
-// (D5), its access a projection of channel membership. All
-// comms flow through this layer, so audit and search are properties of the
-// substrate, not a separate pipeline (D1).
+// permissions. An agent's interactive surface — the session conversation (text
+// and structured asks) plus terminal and file panes — renders in the agent's
+// channel; the AgentWorkspace is the observation pane over that session (D5),
+// its access a projection of channel membership. All comms flow through this
+// layer, so audit and search are properties of the substrate, not a separate
+// pipeline (D1).
 //
 // This lives alongside compass.proto in the same owned `compass.v1` package as
 // an additive surface (new file, new service) that evolves the contract from a
@@ -942,16 +942,16 @@ func (x *PinnedEntry) GetPinnedByAccountId() string {
 	return ""
 }
 
-// An agent's interactive surface: the observation pane for one agent account —
-// the ACP conversation plus the terminal and file panes the ADE hosts. Demoted
-// to the observation pane (D5, fork f): no longer a message container, and its
-// access is a projection of the agent's channel membership rather than a
-// separate participant ACL.
+// An agent's interactive surface: the session observation pane for one agent
+// account, including the conversation, terminal, and file panes the ADE hosts.
+// Demoted to the observation pane (D5, fork f): no longer a message container,
+// and its access is a projection of the agent's channel membership rather than
+// a separate participant ACL.
 type AgentWorkspace struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
 	// Server-assigned stable id.
 	Id string `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
-	// The agent account whose ACP session this surface renders.
+	// The agent account whose session this surface renders.
 	AgentAccountId string `protobuf:"bytes,2,opt,name=agent_account_id,json=agentAccountId,proto3" json:"agent_account_id,omitempty"`
 	unknownFields  protoimpl.UnknownFields
 	sizeCache      protoimpl.SizeCache
@@ -1096,8 +1096,8 @@ func (x *Topic) GetArchived() bool {
 }
 
 // A message in a channel — the persisted unit of the comms layer, held in the
-// Server store of record (D12). An agent's ACP turn is a channel message whose
-// blocks stream in and update as the session runs (see MessageUpdated).
+// Server store of record (D12). An agent turn is a channel message whose blocks
+// stream in and update as the session runs (see MessageUpdated).
 type Message struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
 	// Server-assigned stable id.
@@ -1111,7 +1111,7 @@ type Message struct {
 	// The posting account (a user or an agent).
 	AuthorAccountId string `protobuf:"bytes,3,opt,name=author_account_id,json=authorAccountId,proto3" json:"author_account_id,omitempty"`
 	AtUnixMs        int64  `protobuf:"varint,4,opt,name=at_unix_ms,json=atUnixMs,proto3" json:"at_unix_ms,omitempty"`
-	// Ordered content; mirrors ACP session/update blocks (D5).
+	// Ordered content; mirrors session-update blocks from the SDK (D5).
 	Blocks        []*MessageBlock `protobuf:"bytes,5,rep,name=blocks,proto3" json:"blocks,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
@@ -1183,10 +1183,10 @@ func (x *Message) GetBlocks() []*MessageBlock {
 }
 
 // One content block in a message: the durable conversation the comms layer
-// persists. `text` is settled markdown; `ask` is a structured question the ACP
-// surface needs (D5). The execution trace (thought / tool calls / plans /
-// diffs) is delivered as opaque OMP-native session data on a dedicated stream,
-// not as comms blocks.
+// persists. `text` is settled markdown; `ask` is a structured question the
+// session surface needs (D5). The execution trace (thought / tool calls / plans
+// / diffs) is delivered as opaque OMP-native session data on a dedicated
+// stream, not as comms blocks.
 type MessageBlock struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
 	// Types that are valid to be assigned to Block:
@@ -3884,8 +3884,8 @@ func (x *UpdatePinnedBoardResponse) GetChannel() *Channel {
 
 type OpenAgentWorkspaceRequest struct {
 	state protoimpl.MessageState `protogen:"open.v1"`
-	// The agent account to open the workspace (ACP surface) for. A `@handle`; the
-	// server resolves it to an account id; unknown → NOT_FOUND.
+	// The agent account to open the workspace (session surface) for. A `@handle`;
+	// the server resolves it to an account id; unknown → NOT_FOUND.
 	AgentHandle   string `protobuf:"bytes,1,opt,name=agent_handle,json=agentHandle,proto3" json:"agent_handle,omitempty"`
 	unknownFields protoimpl.UnknownFields
 	sizeCache     protoimpl.SizeCache
diff --git a/go/gen/compass/v1/compassv1connect/comms.connect.go b/go/gen/compass/v1/compassv1connect/comms.connect.go
index 586f47b2..7fe2acd7 100644
--- a/go/gen/compass/v1/compassv1connect/comms.connect.go
+++ b/go/gen/compass/v1/compassv1connect/comms.connect.go
@@ -3,12 +3,12 @@
 // agents are first-class accounts in a management hierarchy. Channels nest in
 // channel groups, so a user's space (e.g. group "matt" → channel
 // "coordination", the path "matt.coordination") carries group-level
-// permissions. An agent's interactive surface — its ACP UI: the conversation
-// (text and structured asks) plus terminal and file panes — renders in the
-// agent's channel; the AgentWorkspace is the observation pane over that session
-// (D5), its access a projection of channel membership. All
-// comms flow through this layer, so audit and search are properties of the
-// substrate, not a separate pipeline (D1).
+// permissions. An agent's interactive surface — the session conversation (text
+// and structured asks) plus terminal and file panes — renders in the agent's
+// channel; the AgentWorkspace is the observation pane over that session (D5),
+// its access a projection of channel membership. All comms flow through this
+// layer, so audit and search are properties of the substrate, not a separate
+// pipeline (D1).
 //
 // This lives alongside compass.proto in the same owned `compass.v1` package as
 // an additive surface (new file, new service) that evolves the contract from a
@@ -152,9 +152,9 @@ type CommsServiceClient interface {
 	// emits AccountChanged; surfaces re-derive the tree from the changed
 	// parent_agent_id with no surface-specific plumbing.
 	ReparentAgent(context.Context, *connect.Request[v1.ReparentAgentRequest]) (*connect.Response[v1.ReparentAgentResponse], error)
-	// Open (or fetch) the caller's agent workspace for an agent — its ACP surface
-	// (D5). Idempotent: created on first open, returned after. Authorized: the
-	// caller must be a member of the agent's channel.
+	// Open (or fetch) the caller's agent workspace for an agent — its session
+	// observation surface (D5). Idempotent: created on first open, returned after.
+	// Authorized: the caller must be a member of the agent's channel.
 	OpenAgentWorkspace(context.Context, *connect.Request[v1.OpenAgentWorkspaceRequest]) (*connect.Response[v1.OpenAgentWorkspaceResponse], error)
 	// Page a channel's message history, newest-first. The channel is one the
 	// caller may see.
@@ -507,9 +507,9 @@ type CommsServiceHandler interface {
 	// emits AccountChanged; surfaces re-derive the tree from the changed
 	// parent_agent_id with no surface-specific plumbing.
 	ReparentAgent(context.Context, *connect.Request[v1.ReparentAgentRequest]) (*connect.Response[v1.ReparentAgentResponse], error)
-	// Open (or fetch) the caller's agent workspace for an agent — its ACP surface
-	// (D5). Idempotent: created on first open, returned after. Authorized: the
-	// caller must be a member of the agent's channel.
+	// Open (or fetch) the caller's agent workspace for an agent — its session
+	// observation surface (D5). Idempotent: created on first open, returned after.
+	// Authorized: the caller must be a member of the agent's channel.
 	OpenAgentWorkspace(context.Context, *connect.Request[v1.OpenAgentWorkspaceRequest]) (*connect.Response[v1.OpenAgentWorkspaceResponse], error)
 	// Page a channel's message history, newest-first. The channel is one the
 	// caller may see.
diff --git a/packages/compass-agent/src/gen/compass/v1/comms_pb.ts b/packages/compass-agent/src/gen/compass/v1/comms_pb.ts
index 94567dca..69d7a924 100644
--- a/packages/compass-agent/src/gen/compass/v1/comms_pb.ts
+++ b/packages/compass-agent/src/gen/compass/v1/comms_pb.ts
@@ -3,12 +3,12 @@
 // agents are first-class accounts in a management hierarchy. Channels nest in
 // channel groups, so a user's space (e.g. group "matt" → channel
 // "coordination", the path "matt.coordination") carries group-level
-// permissions. An agent's interactive surface — its ACP UI: the conversation
-// (text and structured asks) plus terminal and file panes — renders in the
-// agent's channel; the AgentWorkspace is the observation pane over that session
-// (D5), its access a projection of channel membership. All
-// comms flow through this layer, so audit and search are properties of the
-// substrate, not a separate pipeline (D1).
+// permissions. An agent's interactive surface — the session conversation (text
+// and structured asks) plus terminal and file panes — renders in the agent's
+// channel; the AgentWorkspace is the observation pane over that session (D5),
+// its access a projection of channel membership. All comms flow through this
+// layer, so audit and search are properties of the substrate, not a separate
+// pipeline (D1).
 //
 // This lives alongside compass.proto in the same owned `compass.v1` package as
 // an additive surface (new file, new service) that evolves the contract from a
@@ -364,11 +364,11 @@ export const PinnedEntrySchema: GenMessage<PinnedEntry> = /*@__PURE__*/
   messageDesc(file_compass_v1_comms, 6);
 
 /**
- * An agent's interactive surface: the observation pane for one agent account —
- * the ACP conversation plus the terminal and file panes the ADE hosts. Demoted
- * to the observation pane (D5, fork f): no longer a message container, and its
- * access is a projection of the agent's channel membership rather than a
- * separate participant ACL.
+ * An agent's interactive surface: the session observation pane for one agent
+ * account, including the conversation, terminal, and file panes the ADE hosts.
+ * Demoted to the observation pane (D5, fork f): no longer a message container,
+ * and its access is a projection of the agent's channel membership rather than
+ * a separate participant ACL.
  *
  * @generated from message compass.v1.AgentWorkspace
  */
@@ -381,7 +381,7 @@ export type AgentWorkspace = Message$1<"compass.v1.AgentWorkspace"> & {
   id: string;
 
   /**
-   * The agent account whose ACP session this surface renders.
+   * The agent account whose session this surface renders.
    *
    * @generated from field: string agent_account_id = 2;
    */
@@ -455,8 +455,8 @@ export const TopicSchema: GenMessage<Topic> = /*@__PURE__*/
 
 /**
  * A message in a channel — the persisted unit of the comms layer, held in the
- * Server store of record (D12). An agent's ACP turn is a channel message whose
- * blocks stream in and update as the session runs (see MessageUpdated).
+ * Server store of record (D12). An agent turn is a channel message whose blocks
+ * stream in and update as the session runs (see MessageUpdated).
  *
  * @generated from message compass.v1.Message
  */
@@ -492,7 +492,7 @@ export type Message = Message$1<"compass.v1.Message"> & {
   atUnixMs: bigint;
 
   /**
-   * Ordered content; mirrors ACP session/update blocks (D5).
+   * Ordered content; mirrors session-update blocks from the SDK (D5).
    *
    * @generated from field: repeated compass.v1.MessageBlock blocks = 5;
    */
@@ -508,10 +508,10 @@ export const MessageSchema: GenMessage<Message> = /*@__PURE__*/
 
 /**
  * One content block in a message: the durable conversation the comms layer
- * persists. `text` is settled markdown; `ask` is a structured question the ACP
- * surface needs (D5). The execution trace (thought / tool calls / plans /
- * diffs) is delivered as opaque OMP-native session data on a dedicated stream,
- * not as comms blocks.
+ * persists. `text` is settled markdown; `ask` is a structured question the
+ * session surface needs (D5). The execution trace (thought / tool calls / plans
+ * / diffs) is delivered as opaque OMP-native session data on a dedicated
+ * stream, not as comms blocks.
  *
  * @generated from message compass.v1.MessageBlock
  */
@@ -1829,8 +1829,8 @@ export const UpdatePinnedBoardResponseSchema: GenMessage<UpdatePinnedBoardRespon
  */
 export type OpenAgentWorkspaceRequest = Message$1<"compass.v1.OpenAgentWorkspaceRequest"> & {
   /**
-   * The agent account to open the workspace (ACP surface) for. A `@handle`; the
-   * server resolves it to an account id; unknown → NOT_FOUND.
+   * The agent account to open the workspace (session surface) for. A `@handle`;
+   * the server resolves it to an account id; unknown → NOT_FOUND.
    *
    * @generated from field: string agent_handle = 1;
    */
@@ -2616,9 +2616,9 @@ export const CommsService: GenService<{
     output: typeof ReparentAgentResponseSchema;
   },
   /**
-   * Open (or fetch) the caller's agent workspace for an agent — its ACP surface
-   * (D5). Idempotent: created on first open, returned after. Authorized: the
-   * caller must be a member of the agent's channel.
+   * Open (or fetch) the caller's agent workspace for an agent — its session
+   * observation surface (D5). Idempotent: created on first open, returned after.
+   * Authorized: the caller must be a member of the agent's channel.
    *
    * @generated from rpc compass.v1.CommsService.OpenAgentWorkspace
    */
diff --git a/packages/compass-agent/src/mapping.test.ts b/packages/compass-agent/src/mapping.test.ts
index 74279c79..dce4e049 100644
--- a/packages/compass-agent/src/mapping.test.ts
+++ b/packages/compass-agent/src/mapping.test.ts
@@ -564,9 +564,8 @@ describe("EventMapper — tool call title is intent-or-toolName", () => {
 });
 
 describe("EventMapper — tool result output extraction", () => {
-	// The `output` field mirrors the ACP mapper's extractReadableText: a bare
-	// string trimmed, an Error's message, a `text`/`errorMessage`/`message`
-	// property, and a hard cap at 4000 chars (adding "…").
+	// The `output` field renders a bare string trimmed, an Error's message, a
+	// `text`/`errorMessage`/`message` property, capped at 4000 chars with "…".
 	function outputOf(result: unknown): string {
 		const ev = soleTyped(
 			mapper().map({
diff --git a/packages/compass-agent/src/mapping.ts b/packages/compass-agent/src/mapping.ts
index 44074800..291b77dc 100644
--- a/packages/compass-agent/src/mapping.ts
+++ b/packages/compass-agent/src/mapping.ts
@@ -57,9 +57,8 @@ export type MapOutput = OutboundFrame | UnmappedEvent;
 // asserted exactly.
 export type Clock = () => number;
 
-// Cap on emitted tool-call `output` text, mirroring the ACP mapper's ACP_TEXT_LIMIT
-// (acp-event-mapper.ts:130) so a pathological tool result does not put an unbounded
-// string on the wire. The session renderer shows a disclosure, not the full blob.
+// Cap emitted tool-call output at 4,000 characters so pathological results do
+// not put an unbounded string on the wire. The renderer shows a disclosure.
 const OUTPUT_TEXT_LIMIT = 4_000;
 
 // Maps the agent's session-event stream to compass.v1 frames. Stateful on the
@@ -135,10 +134,8 @@ export class EventMapper {
 						}),
 					}),
 				];
-				// The `todo` tool's result is the authoritative plan snapshot — emit a
-				// SessionPlan alongside the tool-call settle (mirrors the ACP mapper's
-				// mapTodoResultToPlanUpdate, acp-event-mapper.ts:378). A failed todo or
-				// an unparseable result yields no plan (the extractor returns undefined).
+				// A successful `todo` result is the authoritative plan snapshot. Emit a
+				// SessionPlan alongside the settled tool call; invalid results emit none.
 				if (event.toolName === "todo" && !event.isError) {
 					const entries = extractPlanEntries(event.result);
 					if (entries !== undefined) {
@@ -153,9 +150,7 @@ export class EventMapper {
 				return out;
 			}
 			case "todo_reminder":
-				// A periodic plan nudge carrying the current todos — emit the plan
-				// snapshot (mirrors the ACP mapper's todo_reminder arm,
-				// acp-event-mapper.ts:247). The todos are already typed on the event.
+				// A periodic SDK reminder carries current todos; emit the plan snapshot.
 				return [
 					this.#sessionEvent({
 						case: "plan",
@@ -170,8 +165,7 @@ export class EventMapper {
 					}),
 				];
 			case "todo_auto_clear":
-				// The todo list was cleared → an empty plan (mirrors
-				// acp-event-mapper.ts:255).
+				// The SDK cleared the todo list; emit an empty plan.
 				return [
 					this.#sessionEvent({
 						case: "plan",
@@ -341,9 +335,8 @@ export class EventMapper {
 }
 
 // ── Runtime-narrowed readers (never an inline cast) ──────────────────────────
-// The SDK types tool `args`/`result`/`partialResult` as `any`; these read them through the
-// `isRecord` guard so every access is on a known-object value. Mirrors the ACP mapper's
-// readers but compass-native (its own target types), not an ACP dependency.
+// The SDK types tool `args`/`result`/`partialResult` as `any`; these read them
+// through the `isRecord` guard so every access is on a known-object value.
 
 // The one narrowing primitive: is `value` a non-null object we can index by key?
 // Every reader below narrows through this before any property read, so there is
@@ -358,10 +351,8 @@ function readString(value: unknown, key: string): string | undefined {
 	return typeof prop === "string" ? prop : undefined;
 }
 
-// A best-effort human-readable rendering of a tool result for the `output` field, mirroring
-// acp-event-mapper.ts extractReadableText: a bare string, an Error's message, a
-// `text`/`errorMessage`/`message` property, else the JSON. Capped at OUTPUT_TEXT_LIMIT;
-// undefined when nothing readable is present (the caller defaults to "").
+// Render a tool result for `output`: strings, Error messages, known text fields,
+// or JSON. Cap at OUTPUT_TEXT_LIMIT; undefined lets the caller default to "".
 function extractReadableText(value: unknown): string | undefined {
 	if (typeof value === "string") return normalizeText(value);
 	if (value instanceof Error) return normalizeText(value.message);
@@ -394,10 +385,8 @@ function safeJsonStringify(value: unknown): string | undefined {
 	}
 }
 
-// Extract file diffs from a tool result, mirroring acp-event-mapper.ts
-// extractDiffToolCallContent: a `details.perFileResults[]` array or the single `details`,
-// each carrying `path` + `oldText`/`newText`. A creation has no `oldText`. Entries flagged
-// `isError` or lacking a path / any text are skipped.
+// Extract file diffs from a tool result's `details.perFileResults[]` or `details`.
+// Skip errors and entries lacking a path or any text.
 function extractDiffs(result: unknown): SessionFileDiff[] {
 	if (!isRecord(result)) return [];
 	const details = result.details;
@@ -427,10 +416,8 @@ function buildDiff(entry: unknown): SessionFileDiff | undefined {
 	});
 }
 
-// Extract plan entries from the `todo` tool result, mirroring acp-event-mapper.ts
-// extractTodoPhases/extractTodoEntries: a `details.phases[].tasks[]` shape, each task a
-// `{ content, status }`. Returns undefined when not a todo snapshot, an empty array when
-// present but with no valid tasks.
+// Extract plan entries from `details.phases[].tasks[]`. Return undefined when the
+// result is not a todo snapshot, or an empty array when it has no valid tasks.
 function extractPlanEntries(result: unknown): AgentPlanEntry[] | undefined {
 	if (!isRecord(result)) return undefined;
 	const details = result.details;
@@ -457,9 +444,8 @@ function extractPlanEntries(result: unknown): AgentPlanEntry[] | undefined {
 	return entries;
 }
 
-// Map an SDK todo status (string literal) to the compass plan-entry status enum,
-// mirroring acp-event-mapper.ts:367 todoStatusMap: "abandoned" folds to COMPLETED
-// (the plan enum has no abandoned state), an unknown/absent status → PENDING.
+// Map an SDK todo status to the Compass plan-entry enum: "abandoned" folds to
+// COMPLETED (the enum has no abandoned state); unknown or absent is PENDING.
 function planStatus(status: unknown): AgentPlanEntryStatus {
 	switch (status) {
 		case "in_progress":
@@ -472,9 +458,8 @@ function planStatus(status: unknown): AgentPlanEntryStatus {
 	}
 }
 
-// A display title for a tool call: the caller-supplied `intent` when present (the agent's own
-// label), else the tool name. The ACP mapper builds elaborate titles; the compass session
-// renderer shows a plain title, so intent-or-name is the faithful-but-simpler rendering.
+// Display the caller's `intent` when present, otherwise the tool name. The
+// session renderer uses this plain title rather than elaborating tool arguments.
 function toolTitle(
 	toolName: string,
 	args: unknown,
@@ -482,8 +467,7 @@ function toolTitle(
 ): string {
 	const trimmed = intent?.trim();
 	if (trimmed !== undefined && trimmed.length > 0) return trimmed;
-	// `args` is accepted for parity with the ACP title builder's signature and to
-	// leave a grounded seam for richer titles; the dumb emitter does not read it.
+	// `args` remains part of the mapper signature for future richer titles.
 	void args;
 	return toolName;
 }
diff --git a/packages/compass-client/src/gen/compass/v1/comms_pb.ts b/packages/compass-client/src/gen/compass/v1/comms_pb.ts
index 94567dca..69d7a924 100644
--- a/packages/compass-client/src/gen/compass/v1/comms_pb.ts
+++ b/packages/compass-client/src/gen/compass/v1/comms_pb.ts
@@ -3,12 +3,12 @@
 // agents are first-class accounts in a management hierarchy. Channels nest in
 // channel groups, so a user's space (e.g. group "matt" → channel
 // "coordination", the path "matt.coordination") carries group-level
-// permissions. An agent's interactive surface — its ACP UI: the conversation
-// (text and structured asks) plus terminal and file panes — renders in the
-// agent's channel; the AgentWorkspace is the observation pane over that session
-// (D5), its access a projection of channel membership. All
-// comms flow through this layer, so audit and search are properties of the
-// substrate, not a separate pipeline (D1).
+// permissions. An agent's interactive surface — the session conversation (text
+// and structured asks) plus terminal and file panes — renders in the agent's
+// channel; the AgentWorkspace is the observation pane over that session (D5),
+// its access a projection of channel membership. All comms flow through this
+// layer, so audit and search are properties of the substrate, not a separate
+// pipeline (D1).
 //
 // This lives alongside compass.proto in the same owned `compass.v1` package as
 // an additive surface (new file, new service) that evolves the contract from a
@@ -364,11 +364,11 @@ export const PinnedEntrySchema: GenMessage<PinnedEntry> = /*@__PURE__*/
   messageDesc(file_compass_v1_comms, 6);
 
 /**
- * An agent's interactive surface: the observation pane for one agent account —
- * the ACP conversation plus the terminal and file panes the ADE hosts. Demoted
- * to the observation pane (D5, fork f): no longer a message container, and its
- * access is a projection of the agent's channel membership rather than a
- * separate participant ACL.
+ * An agent's interactive surface: the session observation pane for one agent
+ * account, including the conversation, terminal, and file panes the ADE hosts.
+ * Demoted to the observation pane (D5, fork f): no longer a message container,
+ * and its access is a projection of the agent's channel membership rather than
+ * a separate participant ACL.
  *
  * @generated from message compass.v1.AgentWorkspace
  */
@@ -381,7 +381,7 @@ export type AgentWorkspace = Message$1<"compass.v1.AgentWorkspace"> & {
   id: string;
 
   /**
-   * The agent account whose ACP session this surface renders.
+   * The agent account whose session this surface renders.
    *
    * @generated from field: string agent_account_id = 2;
    */
@@ -455,8 +455,8 @@ export const TopicSchema: GenMessage<Topic> = /*@__PURE__*/
 
 /**
  * A message in a channel — the persisted unit of the comms layer, held in the
- * Server store of record (D12). An agent's ACP turn is a channel message whose
- * blocks stream in and update as the session runs (see MessageUpdated).
+ * Server store of record (D12). An agent turn is a channel message whose blocks
+ * stream in and update as the session runs (see MessageUpdated).
  *
  * @generated from message compass.v1.Message
  */
@@ -492,7 +492,7 @@ export type Message = Message$1<"compass.v1.Message"> & {
   atUnixMs: bigint;
 
   /**
-   * Ordered content; mirrors ACP session/update blocks (D5).
+   * Ordered content; mirrors session-update blocks from the SDK (D5).
    *
    * @generated from field: repeated compass.v1.MessageBlock blocks = 5;
    */
@@ -508,10 +508,10 @@ export const MessageSchema: GenMessage<Message> = /*@__PURE__*/
 
 /**
  * One content block in a message: the durable conversation the comms layer
- * persists. `text` is settled markdown; `ask` is a structured question the ACP
- * surface needs (D5). The execution trace (thought / tool calls / plans /
- * diffs) is delivered as opaque OMP-native session data on a dedicated stream,
- * not as comms blocks.
+ * persists. `text` is settled markdown; `ask` is a structured question the
+ * session surface needs (D5). The execution trace (thought / tool calls / plans
+ * / diffs) is delivered as opaque OMP-native session data on a dedicated
+ * stream, not as comms blocks.
  *
  * @generated from message compass.v1.MessageBlock
  */
@@ -1829,8 +1829,8 @@ export const UpdatePinnedBoardResponseSchema: GenMessage<UpdatePinnedBoardRespon
  */
 export type OpenAgentWorkspaceRequest = Message$1<"compass.v1.OpenAgentWorkspaceRequest"> & {
   /**
-   * The agent account to open the workspace (ACP surface) for. A `@handle`; the
-   * server resolves it to an account id; unknown → NOT_FOUND.
+   * The agent account to open the workspace (session surface) for. A `@handle`;
+   * the server resolves it to an account id; unknown → NOT_FOUND.
    *
    * @generated from field: string agent_handle = 1;
    */
@@ -2616,9 +2616,9 @@ export const CommsService: GenService<{
     output: typeof ReparentAgentResponseSchema;
   },
   /**
-   * Open (or fetch) the caller's agent workspace for an agent — its ACP surface
-   * (D5). Idempotent: created on first open, returned after. Authorized: the
-   * caller must be a member of the agent's channel.
+   * Open (or fetch) the caller's agent workspace for an agent — its session
+   * observation surface (D5). Idempotent: created on first open, returned after.
+   * Authorized: the caller must be a member of the agent's channel.
    *
    * @generated from rpc compass.v1.CommsService.OpenAgentWorkspace
    */
diff --git a/proto/compass/v1/comms.proto b/proto/compass/v1/comms.proto
index e9d57c5d..8bdb15b5 100644
--- a/proto/compass/v1/comms.proto
+++ b/proto/compass/v1/comms.proto
@@ -3,12 +3,12 @@
 // agents are first-class accounts in a management hierarchy. Channels nest in
 // channel groups, so a user's space (e.g. group "matt" → channel
 // "coordination", the path "matt.coordination") carries group-level
-// permissions. An agent's interactive surface — its ACP UI: the conversation
-// (text and structured asks) plus terminal and file panes — renders in the
-// agent's channel; the AgentWorkspace is the observation pane over that session
-// (D5), its access a projection of channel membership. All
-// comms flow through this layer, so audit and search are properties of the
-// substrate, not a separate pipeline (D1).
+// permissions. An agent's interactive surface — the session conversation (text
+// and structured asks) plus terminal and file panes — renders in the agent's
+// channel; the AgentWorkspace is the observation pane over that session (D5),
+// its access a projection of channel membership. All comms flow through this
+// layer, so audit and search are properties of the substrate, not a separate
+// pipeline (D1).
 //
 // This lives alongside compass.proto in the same owned `compass.v1` package as
 // an additive surface (new file, new service) that evolves the contract from a
@@ -81,9 +81,9 @@ service CommsService {
   // parent_agent_id with no surface-specific plumbing.
   rpc ReparentAgent(ReparentAgentRequest) returns (ReparentAgentResponse);
 
-  // Open (or fetch) the caller's agent workspace for an agent — its ACP surface
-  // (D5). Idempotent: created on first open, returned after. Authorized: the
-  // caller must be a member of the agent's channel.
+  // Open (or fetch) the caller's agent workspace for an agent — its session
+  // observation surface (D5). Idempotent: created on first open, returned after.
+  // Authorized: the caller must be a member of the agent's channel.
   rpc OpenAgentWorkspace(OpenAgentWorkspaceRequest) returns (OpenAgentWorkspaceResponse);
 
   // Page a channel's message history, newest-first. The channel is one the
@@ -296,15 +296,15 @@ enum ChannelKind {
 
 // ── Agent workspace (D5) ─────────────────────────────────────────────────────
 
-// An agent's interactive surface: the observation pane for one agent account —
-// the ACP conversation plus the terminal and file panes the ADE hosts. Demoted
-// to the observation pane (D5, fork f): no longer a message container, and its
-// access is a projection of the agent's channel membership rather than a
-// separate participant ACL.
+// An agent's interactive surface: the session observation pane for one agent
+// account, including the conversation, terminal, and file panes the ADE hosts.
+// Demoted to the observation pane (D5, fork f): no longer a message container,
+// and its access is a projection of the agent's channel membership rather than
+// a separate participant ACL.
 message AgentWorkspace {
   // Server-assigned stable id.
   string id = 1;
-  // The agent account whose ACP session this surface renders.
+  // The agent account whose session this surface renders.
   string agent_account_id = 2;
 }
 
@@ -332,8 +332,8 @@ message Topic {
 // ── Messages + content blocks (D5) ─────────────────────────────────────────
 
 // A message in a channel — the persisted unit of the comms layer, held in the
-// Server store of record (D12). An agent's ACP turn is a channel message whose
-// blocks stream in and update as the session runs (see MessageUpdated).
+// Server store of record (D12). An agent turn is a channel message whose blocks
+// stream in and update as the session runs (see MessageUpdated).
 message Message {
   // Server-assigned stable id.
   string id = 1;
@@ -346,15 +346,15 @@ message Message {
   // The posting account (a user or an agent).
   string author_account_id = 3;
   int64 at_unix_ms = 4;
-  // Ordered content; mirrors ACP session/update blocks (D5).
+  // Ordered content; mirrors session-update blocks from the SDK (D5).
   repeated MessageBlock blocks = 5;
 }
 
 // One content block in a message: the durable conversation the comms layer
-// persists. `text` is settled markdown; `ask` is a structured question the ACP
-// surface needs (D5). The execution trace (thought / tool calls / plans /
-// diffs) is delivered as opaque OMP-native session data on a dedicated stream,
-// not as comms blocks.
+// persists. `text` is settled markdown; `ask` is a structured question the
+// session surface needs (D5). The execution trace (thought / tool calls / plans
+// / diffs) is delivered as opaque OMP-native session data on a dedicated
+// stream, not as comms blocks.
 message MessageBlock {
   oneof block {
     // Settled user-facing / assistant text (markdown).
@@ -800,8 +800,8 @@ message UpdatePinnedBoardResponse {
 }
 
 message OpenAgentWorkspaceRequest {
-  // The agent account to open the workspace (ACP surface) for. A `@handle`; the
-  // server resolves it to an account id; unknown → NOT_FOUND.
+  // The agent account to open the workspace (session surface) for. A `@handle`;
+  // the server resolves it to an account id; unknown → NOT_FOUND.
   string agent_handle = 1;
 }