diff --git a/apps/cli/README.md b/apps/cli/README.md
index 4ff9034dd3..50571632c0 100644
--- a/apps/cli/README.md
+++ b/apps/cli/README.md
@@ -14,6 +14,8 @@ The TUI surface:
 
 The Web and headless surfaces boot one shared composition (`cordis.yml`): both treat the invoking directory as the default project and Workspace root, create named Workspaces beneath that root unless `--workspace-root <path>` overrides it, load applicable `AGENTS.md`/`CLAUDE.md` instructions into each agent-loop request prefix with a 65,536-byte render budget, and opt into first-message model titles. Headless differs only in listening on an OS-assigned port (parallel `dsh -p` runs never collide; the stderr-printed URL opens the live session in a browser). Both need the frontend dist and client bundles built (`pnpm run build && pnpm run build:web`).
 
+`DSH_TOOLS_MODE` selects the tool presentation mode for the whole Web/headless process: `native` (the schema default when unset), `code` (the `run_code`-only Code Mode wire), or `both`; any other value fails loud at boot through the `dsh-tools` config schema. It is a TEMPORARY seam — process-wide because Loader composition is static — and is removed once the web UI owns per-session tool-mode selection; the TUI surface ignores it (its config tree pins its own mode).
+
 ## Install (developer machine)
 
 Symlink the source-running launcher onto your PATH; it resolves the checkout through its own real path, so code changes apply on the next launch with no build step:
diff --git a/packages/client/runtime/README.md b/packages/client/runtime/README.md
index 12bfaa459b..2768a8a58d 100644
--- a/packages/client/runtime/README.md
+++ b/packages/client/runtime/README.md
@@ -14,7 +14,7 @@ SlotsService gives the renderer separate bare observables for `useSessions` and
 
 ## Code Mode sub-dispatch index
 
-`ConversationSnapshot.codeDispatches` groups a `run_code` call's sub-dispatches under their parent callId, in start order, using the native call-block shapes: a started-but-unsettled sub-call is a `RunningToolCall` (rows derive the running ring from the shape) and its `tool/code-dispatch` settlement replaces it in place with the `ToolResultNode` form, `callTime` carrying the paired start's time. Live mux frames and history replay build the identical index; sub-calls never join the surface `nodes` flow; per-parent array and map references are memo-stable across unrelated snapshot swaps.
+`ConversationSnapshot.codeDispatches` groups a `run_code` call's sub-dispatches under their parent callId, in start order, using the native call-block shapes: a `tool/code-dispatch-start` event lands the `RunningToolCall` form (rows derive the running ring from the shape) and its `tool/code-dispatch` settlement replaces it in place with the `ToolResultNode` form, `callTime` carrying the paired start's time. A settle whose start fell outside the replay window appends directly with `callTime: null` (duration unknown — never a fabricated zero). Live mux frames and history replay build the identical index; sub-calls never join the surface `nodes` flow; per-parent array and map references are memo-stable across unrelated snapshot swaps.
 
 ## Session title projection
 
diff --git a/packages/client/runtime/tests/session.spec.ts b/packages/client/runtime/tests/session.spec.ts
index 43745a8324..f5cf9a2138 100644
--- a/packages/client/runtime/tests/session.spec.ts
+++ b/packages/client/runtime/tests/session.spec.ts
@@ -685,6 +685,9 @@ describe('run_code sub-dispatch indexing', () => {
     expect(subs?.[0]).toMatchObject({
       kind: 'tool-result', callId: 'p1:code:1',
       call: { name: 'bash', argsRaw: '{"command":"ls","description":"列目录"}' },
+      // The settle event carries no start time: callTime stays null (never a
+      // fabricated zero-duration).
+      callTime: null,
       isError: false, content: [{ type: 'text', text: 'demo.txt' }],
     })
     expect(subs?.[1]).toMatchObject({ callId: 'p1:code:2', isError: true })