src/__tests__/markdown.test.ts

@@ -1,10 +1,5 @@
 import { describe, expect, it } from "vitest";
-import {
-  STREAMING_CURSOR,
-  buildThreadMarkdown,
-  quote,
-  sessionToPlainText,
-} from "../lib/markdown";
+import { STREAMING_CURSOR, buildThreadMarkdown, quote, sessionToPlainText } from "../lib/markdown";
 import type { ChatTurn, ThreadMessage } from "../lib/types";
 
 function message(overrides: Partial<ThreadMessage> & Pick<ThreadMessage, "role">): ThreadMessage {
@@ -235,9 +230,7 @@ describe("buildThreadMarkdown", () => {
   });
 
   it("links a lone URL the model put in inline code", () => {
-    const markdown = buildThreadMarkdown([
-      message({ role: "assistant", text: "`https://example.com`" }),
-    ]);
+    const markdown = buildThreadMarkdown([message({ role: "assistant", text: "`https://example.com`" })]);
 
     expect(markdown).not.toContain("```");
     expect(markdown).toContain("[https://example.com](https://example.com)");
@@ -655,3 +648,73 @@ describe("attachments in the transcript", () => {
     expect(text).toContain("_(screenshot attached)_");
   });
 });
+
+describe("sources", () => {
+  const sources = [
+    { index: 1, title: "First", url: "https://first.example" },
+    { index: 2, title: "Second", url: "https://second.example" },
+  ];
+
+  /** One search, and the answer that may or may not point at it. */
+  function answered(text: string, streaming = false): string {
+    return buildThreadMarkdown(
+      [
+        message({
+          id: "t1:assistant",
+          role: "assistant",
+          text,
+          isStreaming: streaming,
+          toolCalls: [{ name: "web_search", arguments: {}, result: "", isError: false, sources }],
+        }),
+        message({ id: "t1:user", role: "user", text: "When is the rain?" }),
+      ],
+      { showToolCalls: false, showReasoning: false },
+    );
+  }
+
+  it("links the markers and lists the sources the answer leaned on", () => {
+    const text = answered("Rain is likely [1].");
+
+    expect(text).toContain("Rain is likely [\\[1\\]](https://first.example).");
+    expect(text).toContain("_Sources_");
+    expect(text).toContain("- [\\[1\\]](https://first.example) First");
+    // The answer did not lean on the second one.
+    expect(text).not.toContain("Second");
+  });
+
+  it("lists everything the turn consulted when the answer cited nothing", () => {
+    const text = answered("Rain is likely.");
+
+    expect(text).toContain("- [\\[1\\]](https://first.example) First");
+    expect(text).toContain("- [\\[2\\]](https://second.example) Second");
+  });
+
+  it("waits for a citation before drawing anything", () => {
+    // Otherwise the list arrives in full with the first token and then shrinks as
+    // citations appear, which reads as a glitch rather than as settling.
+    expect(answered("Rain is", true)).not.toContain("_Sources_");
+  });
+
+  it("adds nothing to a turn that consulted nothing", () => {
+    expect(buildThreadMarkdown([message({ role: "assistant", text: "Plain." })])).toBe("Plain.");
+  });
+
+  it("carries the list into the copied conversation", () => {
+    const copied = sessionToPlainText([
+      {
+        id: "t1",
+        prompt: "When is the rain?",
+        response: "Rain [1].",
+        thinking: "",
+        model: "m",
+        createdAt: 0,
+        toolCalls: [{ name: "web_search", arguments: {}, result: "", isError: false, sources }],
+        attachments: [],
+      },
+    ]);
+
+    expect(copied).toContain("**Lam**\n\nRain [1].");
+    expect(copied).toContain("_Sources_");
+    expect(copied).toContain("- [\\[1\\]](https://first.example) First");
+  });
+});

src/lib/markdown.ts

@@ -1,5 +1,6 @@
 import { imageSource } from "./attachments";
-import { renderInlineContent, renderModelOutput } from "./render";
+import { citedIndices, collectSources, renderSources } from "./citations";
+import { renderInlineContent, renderModelOutput, type RenderedMarkdown } from "./render";
 import { describeActivity } from "./thread";
 import type { Attachment, ChatTurn, ThreadMessage, ToolCallRecord } from "./types";
 
@@ -150,11 +151,20 @@ function renderMessage(message: ThreadMessage, options: TranscriptOptions): stri
 
   /** The answer, or whatever stands in for it while there is none. */
   const answered = message.text.trim();
+  /**
+   * The turn's sources, read back off its records rather than out of a tool result
+   * string, so a reopened conversation draws the same list with the same numbers.
+   */
+  const sources = collectSources(message.toolCalls);
+  const drawn: RenderedMarkdown = answered
+    ? // One pass, in one place: fences get their languages and links recovered, then
+      // TeX becomes something drawable, a citation marker becomes a link to the page
+      // it names, and the HTML around all of it is filtered to the subset the
+      // renderer acts on. See `render.ts` for the order and why.
+      renderModelOutput(answered, { sources })
+    : { text: "", cited: new Set<number>() };
   const body = answered
-    ? // One pass, in one place: fences get their languages and links recovered,
-      // then TeX becomes something drawable and the HTML around it is filtered to
-      // the subset the renderer acts on. See `render.ts` for the order and why.
-      renderModelOutput(answered).text
+    ? drawn.text
     : !message.isStreaming
       ? "_No response._"
       : activityLine
@@ -178,6 +188,14 @@ function renderMessage(message: ThreadMessage, options: TranscriptOptions): stri
   // something went wrong and should not be skimmed past.
   if (message.error) sections.push("", `**Error:** ${message.error}`);
 
+  /**
+   * Sources belong to the answer rather than to the tool list, so they are drawn
+   * whether or not the user asked to see tool calls. Hiding the activity line is
+   * about chrome; a citation list is the answer's own provenance.
+   */
+  const list = renderSources(sources, drawn.cited, message.isStreaming);
+  if (list) sections.push("", list);
+
   /**
    * Tool calls are a display preference. When they are on, every tool is named
    * once. When they are off, nothing is listed; a failure or a refused repeat
@@ -276,7 +294,16 @@ export function sessionToPlainText(turns: ChatTurn[]): string {
       const attached = turn.attachments.length > 0 ? "\n\n_(screenshot attached)_" : "";
       const answer = turn.response.trim() || (turn.error ? "" : "_(no response)_");
       const failure = turn.error ? `\n\n**[error]** ${turn.error}` : "";
-      return `${question}${attached}\n\n**Lam**\n\n${answer}${failure}`;
+      /**
+       * The same list the transcript draws, worked out from a plain scan rather than
+       * from the panel's own set. A copied conversation is markdown on its way
+       * somewhere else, where a `[1]` inside a snippet counting as a citation costs a
+       * reader nothing.
+       */
+      const sources = collectSources(turn.toolCalls);
+      const list = renderSources(sources, citedIndices(turn.response, sources), false);
+      const cited = list ? `\n\n${list}` : "";
+      return `${question}${attached}\n\n**Lam**\n\n${answer}${failure}${cited}`;
     })
     .join("\n\n---\n\n");
 }