diff --git a/apps/mobile/src/features/pull-requests/PullRequestMarkdown.tsx b/apps/mobile/src/features/pull-requests/PullRequestMarkdown.tsx
index 05fe4b444a6ef..0d5b77f061837 100644
--- a/apps/mobile/src/features/pull-requests/PullRequestMarkdown.tsx
+++ b/apps/mobile/src/features/pull-requests/PullRequestMarkdown.tsx
@@ -15,6 +15,7 @@ import {
 import { videoMimeType } from "@t3tools/shared/video";
 import { createContext, useContext, useMemo, useState } from "react";
 import {
+  changeRequestLinkResolver,
   changeRequestReferenceAutolinker,
   resolveChangeRequestMediaUrl,
 } from "@t3tools/client-runtime/pull-request-markdown";
@@ -22,21 +23,28 @@ import {
   sourceControlClients,
   type ReferenceAutolink,
 } from "@t3tools/client-runtime/source-control-clients";
+import { assetUrlStateFromResult } from "@t3tools/client-runtime/state/assets";
 import { linkReferenceAutolinks } from "./pullRequestAutolinks";
+import { assetEnvironment } from "../../state/assets";
+import { usePreparedConnection } from "../../state/session";
+import { useAtomQueryRunner } from "../../state/use-atom-query-runner";
 
 import { useOpenPullRequest } from "../../native/useOpenPullRequest";
 import { SelectableMarkdownText } from "../../native/SelectableMarkdownText";
 import { useMarkdownPreviewStyles } from "../files/FileMarkdownPreview";
 import { markdownImageSources } from "../../lib/markdownImageSources";
 import { FilePreviewGallery, useFilePreviewGallery } from "../../components/ui/FilePreviewGallery";
-import { pullRequestImageSource } from "./pullRequestMediaSource";
+import { pullRequestImageSource, pullRequestMediaSource } from "./pullRequestMediaSource";
 import {
   FilePreviewModal,
   type FilePreviewSource,
   type FilePreviewItem,
 } from "../../components/ui/FilePreviewModal";
 import { ThreadMarkdownImageView } from "../threads/ThreadMarkdownImage";
-import type { MarkdownImageRenderer } from "../../native/SelectableMarkdownText";
+import type {
+  MarkdownImageRenderer,
+  MarkdownImageSourceResolver,
+} from "../../native/SelectableMarkdownText";
 import type { SelectableMarkdownTextProps } from "../../native/SelectableMarkdownText.types";
 
 const AutolinksContext = createContext<((text: string) => ReadonlyArray<ReferenceAutolink>) | null>(
@@ -44,6 +52,7 @@ const AutolinksContext = createContext<((text: string) => ReadonlyArray<Referenc
 );
 const LineBreaksContext = createContext(false);
 const ChangeRequestUrlContext = createContext<string | null>(null);
+const LinkResolverContext = createContext<((url: string) => string) | null>(null);
 
 export function PullRequestMarkdownRepository(props: {
   /** The change request the markdown belongs to, whose host decides what its text links. */
@@ -58,6 +67,7 @@ export function PullRequestMarkdownRepository(props: {
       ? null
       : changeRequestReferenceAutolinker({ provider, url });
   const lineBreaks = sourceControlClients.find(provider ?? "")?.hardLineBreaks ?? false;
+  const linkResolver = changeRequestLinkResolver(props.changeRequest);
   const target = pullRequestTarget(props.params);
   const project = useProject({
     environmentId: target.environmentId,
@@ -71,13 +81,63 @@ export function PullRequestMarkdownRepository(props: {
     <AutolinksContext value={autolinks}>
       <LineBreaksContext value={lineBreaks}>
         <ChangeRequestUrlContext value={url ?? null}>
-          <PullRequestMediaContext value={media}>{props.children}</PullRequestMediaContext>
+          <LinkResolverContext value={linkResolver}>
+            <PullRequestMediaContext value={media}>{props.children}</PullRequestMediaContext>
+          </LinkResolverContext>
         </ChangeRequestUrlContext>
       </LineBreaksContext>
     </AutolinksContext>
   );
 }
 
+/** A body's destinations, as its host resolves them; a guide's stay relative to the checkout. */
+function useResolveLink() {
+  const linkResolver = useContext(LinkResolverContext);
+  return (href: string) => linkResolver?.(href) ?? href;
+}
+
+function useResolveMediaUrl() {
+  const resolveLink = useResolveLink();
+  const changeRequestUrl = useContext(ChangeRequestUrlContext);
+  return (href: string) => {
+    const url = resolveLink(href);
+    return changeRequestUrl ? resolveChangeRequestMediaUrl(url, changeRequestUrl) : url;
+  };
+}
+
+/**
+ * Enriched draws an image in a table, list or link itself, from this source, not `renderImage`.
+ * It keeps a resolved source for the life of the view, so the view is keyed to everything an
+ * answer depends on: the change request it resolves against, the media location and the origin.
+ */
+function usePullRequestImageSource(resolve: (url: string) => string): {
+  readonly resolveImageSource: MarkdownImageSourceResolver;
+  readonly sourceKey: string;
+} {
+  const location = useContext(PullRequestMediaContext);
+  const connection = usePreparedConnection(location?.environmentId ?? null);
+  const httpBaseUrl = connection._tag === "Some" ? connection.value.httpBaseUrl : null;
+  const createUrl = useAtomQueryRunner(assetEnvironment.createUrl, { reportFailure: false });
+  const resolveImageSource: MarkdownImageSourceResolver = async (image) => {
+    const url = resolve(image.href);
+    const source = pullRequestMediaSource(url, location);
+    if ("uri" in source) return /^https?:\/\//i.test(url) ? { uri: url } : null;
+    const state = assetUrlStateFromResult(
+      await createUrl({
+        environmentId: source.environmentId,
+        input: { resource: source.resource },
+      }),
+      httpBaseUrl,
+    );
+    if (state._tag !== "Success") throw new Error("Pull request image is unavailable");
+    return { uri: state.url };
+  };
+  return {
+    resolveImageSource,
+    sourceKey: `${location?.environmentId ?? ""}\n${location?.cwd ?? ""}\n${httpBaseUrl ?? ""}`,
+  };
+}
+
 function MarkdownImage(props: {
   readonly href: string;
   readonly alt: string | null;
@@ -120,13 +180,13 @@ export function PullRequestMarkdown(props: {
   }) => boolean;
 }) {
   const mediaContext = useContext(PullRequestMediaContext);
-  const changeRequestUrl = useContext(ChangeRequestUrlContext);
+  const resolveMediaUrl = useResolveMediaUrl();
   const segments = useMemo(() => splitPullRequestBody(props.markdown), [props.markdown]);
   const [undoneTicks, setUndoneTicks] = useState(0);
   const gallery: FilePreviewItem[] = markdownImageSources(
     props.imageGroupMarkdown ?? props.markdown,
   )
-    .map((href) => (changeRequestUrl ? resolveChangeRequestMediaUrl(href, changeRequestUrl) : href))
+    .map(resolveMediaUrl)
     .filter(
       (uri) =>
         /^https?:\/\//i.test(uri) &&
@@ -149,6 +209,15 @@ export function PullRequestMarkdown(props: {
   );
 }
 
+/** The agent writes the guide about the checkout, so its relative links name workspace files. */
+export function PullRequestGuideMarkdown(props: { readonly markdown: string }) {
+  return (
+    <LinkResolverContext value={null}>
+      <PullRequestMarkdown lineBreaks={false} markdown={props.markdown} />
+    </LinkResolverContext>
+  );
+}
+
 function PullRequestBodySegmentView(props: {
   readonly segment: PullRequestBodySegment;
   readonly gallery: FilePreviewItem[];
@@ -221,26 +290,30 @@ function PullRequestMarkdownContent(props: {
   const autolinks = useContext(AutolinksContext);
   const mediaContext = useContext(PullRequestMediaContext);
   const changeRequestUrl = useContext(ChangeRequestUrlContext);
-  const resolveMediaUrl = (href: string) =>
-    changeRequestUrl ? resolveChangeRequestMediaUrl(href, changeRequestUrl) : href;
+  const resolveLink = useResolveLink();
+  const resolveMediaUrl = useResolveMediaUrl();
   const markdown = linkReferenceAutolinks(props.markdown, autolinks);
   const openPullRequest = useOpenPullRequest();
   const openLink = (href: string) => {
-    void openPullRequest(href);
+    void openPullRequest(resolveLink(href));
   };
   const [preview, setPreview] = useState<FilePreviewSource | null>(null);
   const renderImage: MarkdownImageRenderer = (image) => (
     <MarkdownImage href={resolveMediaUrl(image.href)} alt={image.alt} onPreview={setPreview} />
   );
+  const { resolveImageSource, sourceKey } = usePullRequestImageSource(resolveMediaUrl);
+  const nativeKey = `${changeRequestUrl ?? ""}\n${sourceKey}`;
   const styles = useMarkdownPreviewStyles();
   return (
     <FilePreviewGallery value={props.gallery}>
       <SelectableMarkdownText
+        key={nativeKey}
         markdown={markdown}
         preserveSoftBreaks={props.lineBreaks ?? hostLineBreaks}
         textStyle={styles.nativeTextStyle}
         onLinkPress={openLink}
         renderImage={renderImage}
+        resolveImageSource={resolveImageSource}
         onImagePress={(href) =>
           setPreview(pullRequestImageSource(resolveMediaUrl(href), mediaContext))
         }
diff --git a/apps/mobile/src/features/pull-requests/guide/GuideOutline.tsx b/apps/mobile/src/features/pull-requests/guide/GuideOutline.tsx
index 9fd845eff921e..4301a84be72c2 100644
--- a/apps/mobile/src/features/pull-requests/guide/GuideOutline.tsx
+++ b/apps/mobile/src/features/pull-requests/guide/GuideOutline.tsx
@@ -4,7 +4,7 @@ import { stopFilePaths } from "@t3tools/client-runtime/review-guide-tour";
 import { Pressable, View } from "react-native";
 import { AppText as Text } from "../../../components/ui/AppText";
 import { SymbolView } from "../../../components/ui/AppSymbol";
-import { PullRequestMarkdown } from "../PullRequestMarkdown";
+import { PullRequestGuideMarkdown } from "../PullRequestMarkdown";
 import { Menu } from "../../../components/ui/Menu";
 
 import { useAppearancePreferences } from "../../settings/appearance/AppearancePreferencesProvider";
@@ -59,7 +59,7 @@ export function GuideOutline({
       </View>
       {guide.stops[0]?.summary ? (
         <View className="mb-6">
-          <PullRequestMarkdown lineBreaks={false} markdown={guide.stops[0].summary} />
+          <PullRequestGuideMarkdown markdown={guide.stops[0].summary} />
         </View>
       ) : null}
       {guide.stops.map((stop, position) => {
diff --git a/apps/mobile/src/features/pull-requests/guide/PullRequestGuideScreen.tsx b/apps/mobile/src/features/pull-requests/guide/PullRequestGuideScreen.tsx
index 542700dc69185..66ff23dffb829 100644
--- a/apps/mobile/src/features/pull-requests/guide/PullRequestGuideScreen.tsx
+++ b/apps/mobile/src/features/pull-requests/guide/PullRequestGuideScreen.tsx
@@ -17,7 +17,7 @@ import { AppText as Text } from "../../../components/ui/AppText";
 import { ScreenScrollView } from "../../../components/ui/ScreenScrollView";
 import { useAppearancePreferences } from "../../settings/appearance/AppearancePreferencesProvider";
 import { PullRequestCardGroup, PullRequestCardRow } from "../PullRequestControls";
-import { PullRequestMarkdown, PullRequestMarkdownRepository } from "../PullRequestMarkdown";
+import { PullRequestGuideMarkdown, PullRequestMarkdownRepository } from "../PullRequestMarkdown";
 import { usePullRequestDiff, type PullRequestParams } from "../usePullRequestDiff";
 import { ReviewGuideExcerpt } from "./ReviewGuideExcerpt";
 import { reviewGuideState } from "./reviewGuideState";
@@ -163,7 +163,7 @@ export function PullRequestGuideStopScreen({ route }: StaticScreenProps<GuideSto
               <>
                 <GuideNotice state={state} />
                 <Text className="text-2xl leading-8 font-t3-semibold">{stop.title}</Text>
-                <PullRequestMarkdown lineBreaks={false} markdown={stop.summary} />
+                <PullRequestGuideMarkdown markdown={stop.summary} />
                 {stop.attention ? (
                   <View className="gap-3 rounded-xl border border-border bg-grouped-card p-4">
                     <View className="flex-row items-center gap-2">
@@ -172,7 +172,7 @@ export function PullRequestGuideStopScreen({ route }: StaticScreenProps<GuideSto
                         {attentionLabels[stop.attention.kind]}
                       </Text>
                     </View>
-                    <PullRequestMarkdown lineBreaks={false} markdown={stop.attention.note} />
+                    <PullRequestGuideMarkdown markdown={stop.attention.note} />
                   </View>
                 ) : null}
                 {stale ? (
@@ -212,7 +212,7 @@ export function PullRequestGuideStopScreen({ route }: StaticScreenProps<GuideSto
                           <Text className="text-xs text-foreground-muted">
                             {note.path.split("/").at(-1)}:{note.line}
                           </Text>
-                          <PullRequestMarkdown lineBreaks={false} markdown={note.body} />
+                          <PullRequestGuideMarkdown markdown={note.body} />
                         </View>
                       </View>
                     ))}
@@ -241,7 +241,7 @@ export function PullRequestGuideStopScreen({ route }: StaticScreenProps<GuideSto
                   <View className="gap-3">
                     <Text className="font-t3-semibold">Questions to consider</Text>
                     {stop.questions.map((question) => (
-                      <PullRequestMarkdown key={question} lineBreaks={false} markdown={question} />
+                      <PullRequestGuideMarkdown key={question} markdown={question} />
                     ))}
                   </View>
                 ) : null}
diff --git a/apps/mobile/src/features/pull-requests/guide/ReviewGuideExcerpt.tsx b/apps/mobile/src/features/pull-requests/guide/ReviewGuideExcerpt.tsx
index c280c6ea46525..4700a15520b3a 100644
--- a/apps/mobile/src/features/pull-requests/guide/ReviewGuideExcerpt.tsx
+++ b/apps/mobile/src/features/pull-requests/guide/ReviewGuideExcerpt.tsx
@@ -11,7 +11,7 @@ import { buildReviewParsedDiff } from "../../review/reviewModel";
 import { useNativeReviewDiffBridge } from "../../review/useNativeReviewDiffBridge";
 import { useAppearanceCodeSurface } from "../../settings/appearance/useAppearanceCodeSurface";
 import { useAppearancePreferences } from "../../settings/appearance/AppearancePreferencesProvider";
-import { PullRequestMarkdown } from "../PullRequestMarkdown";
+import { PullRequestGuideMarkdown } from "../PullRequestMarkdown";
 
 const EMPTY_IDS: readonly string[] = [];
 
@@ -55,9 +55,7 @@ export function ReviewGuideExcerpt({
   const [NativeDiff] = useState(() => resolveNativeReviewDiffView());
   return (
     <View className="gap-3">
-      {excerpt.caption.trim() ? (
-        <PullRequestMarkdown lineBreaks={false} markdown={excerpt.caption} />
-      ) : null}
+      {excerpt.caption.trim() ? <PullRequestGuideMarkdown markdown={excerpt.caption} /> : null}
       <View className="overflow-hidden rounded-lg border border-border-subtle">
         <Pressable
           accessibilityRole="button"
diff --git a/apps/web/src/components/ChatMarkdown.browser.test.tsx b/apps/web/src/components/ChatMarkdown.browser.test.tsx
index b03612507f917..c91a08d63189d 100644
--- a/apps/web/src/components/ChatMarkdown.browser.test.tsx
+++ b/apps/web/src/components/ChatMarkdown.browser.test.tsx
@@ -121,6 +121,7 @@ vi.mock(import("../hooks/useSettings"), async (original) => {
 
 import ChatMarkdown from "./ChatMarkdown";
 import { AudioPreview } from "./files/AudioPreview";
+import { pullRequestRehypePlugins } from "./pullRequest/pullRequestMarkdown.logic";
 
 it("keeps compact audio playback loaded across signed URL renewals", async () => {
   const original =
@@ -275,6 +276,39 @@ it("reuses the parse of a remounted message that has stable extra plugins", asyn
   expect(parsed).toHaveBeenCalledTimes(1);
 });
 
+it("resolves destinations in parsed html and reference links, but not code", async () => {
+  setup();
+  const extraRehypePlugins = pullRequestRehypePlugins({
+    provider: "github",
+    url: "https://github.com/team/repo/pull/8",
+  });
+  await using screen = await renderText(
+    [
+      '<img alt="before > after" src="/team/repo/blob/abc/a.png">',
+      "",
+      `<img alt="b" title="src='example'" src="../blob/abc/b.png">`,
+      "",
+      '<a href="../blob/abc/docs.md">docs</a> [ref][r] `![c](../blob/abc/c.png)`',
+      "",
+      "[r]: ../blob/abc/ref.md",
+    ].join("\n"),
+    { extraRehypePlugins },
+  );
+  await expect
+    .element(screen.getByAltText("before > after"))
+    .toHaveAttribute("src", "https://github.com/team/repo/blob/abc/a.png");
+  await expect
+    .element(screen.getByAltText("b"))
+    .toHaveAttribute("src", "https://github.com/team/repo/blob/abc/b.png");
+  await expect
+    .element(screen.getByRole("link", { name: "docs" }))
+    .toHaveAttribute("href", "https://github.com/team/repo/blob/abc/docs.md");
+  await expect
+    .element(screen.getByRole("link", { name: "ref" }))
+    .toHaveAttribute("href", "https://github.com/team/repo/blob/abc/ref.md");
+  await expect.element(screen.getByText("![c](../blob/abc/c.png)", { exact: true })).toBeVisible();
+});
+
 describe("ChatMarkdown favicon privacy", () => {
   it("suppresses private link images while preserving public links across updates", async () => {
     setup();
diff --git a/apps/web/src/components/ChatMarkdown.tsx b/apps/web/src/components/ChatMarkdown.tsx
index 0b0116be549cb..d445e34271b7e 100644
--- a/apps/web/src/components/ChatMarkdown.tsx
+++ b/apps/web/src/components/ChatMarkdown.tsx
@@ -251,6 +251,8 @@ interface ChatMarkdownProps {
   /** The change request's repository, when it can differ from the checkout at `cwd`. */
   sourceControlMediaRepository?: string | undefined;
   headingLevelOffset?: number | undefined;
+  /** Run after raw HTML is parsed and sanitized; keep the list stable to share the parse cache. */
+  extraRehypePlugins?: PluggableList;
 }
 
 export interface ChatMarkdownContextReference {
@@ -261,6 +263,7 @@ export interface ChatMarkdownContextReference {
 
 const EMPTY_MARKDOWN_SKILLS: ReadonlyArray<ServerProviderSkill> = [];
 const EMPTY_REMARK_PLUGINS: NonNullable<ReactMarkdownOptions["remarkPlugins"]> = [];
+const EMPTY_REHYPE_PLUGINS: PluggableList = [];
 
 const ARTIFACT_TEMPLATE_ICON_BY_KIND = {
   document: FileTextIcon,
@@ -1746,6 +1749,7 @@ function ChatMarkdown({
   lineBreaks = false,
   parseRawHtml = true,
   extraRemarkPlugins = EMPTY_REMARK_PLUGINS,
+  extraRehypePlugins = EMPTY_REHYPE_PLUGINS,
   ...props
 }: ChatMarkdownProps) {
   const { componentState, handleCopy, markdownRef, localMediaPreview, closeLocalMediaPreview } =
@@ -1803,11 +1807,12 @@ function ChatMarkdown({
             key={index}
             text={source}
             remarkPlugins={remarkPlugins}
-            rehypePlugins={
+            rehypePlugins={withExtraPlugins(
               parseRawHtml
                 ? CHAT_MARKDOWN_RENDER_REHYPE_PLUGINS
-                : CHAT_MARKDOWN_LITERAL_HTML_REHYPE_PLUGINS
-            }
+                : CHAT_MARKDOWN_LITERAL_HTML_REHYPE_PLUGINS,
+              extraRehypePlugins,
+            )}
             shared={!uncachedPlugins}
             // Every block before the last is finished, so its parse can be reused.
             cache={!props.isStreaming || index < blocks.length - 1}
diff --git a/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx b/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
index 81dea810bb0d0..09f0b187292b5 100644
--- a/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
+++ b/apps/web/src/components/pullRequest/PullRequestDetailPanel.tsx
@@ -112,7 +112,7 @@ import { PullRequestsUnavailableState } from "./PullRequestsUnavailableState";
 import type { PullRequestAgentSelectionInput } from "./PullRequestCodeTab";
 import { openOnHostLabel } from "./pullRequestLinkContextMenu";
 import { PullRequestMarkdownContext } from "./PullRequestMarkdown";
-import { pullRequestMarkdownPlugins } from "./pullRequestMarkdown.logic";
+import { pullRequestMarkdownPlugins, pullRequestRehypePlugins } from "./pullRequestMarkdown.logic";
 import { PullRequestComposer } from "./PullRequestComposer";
 import { PullRequestSummaryTab } from "./PullRequestSummaryTab";
 import { PullRequestTimelineTab } from "./PullRequestTimelineTab";
@@ -244,6 +244,7 @@ function pullRequestMarkdownContext(
 ) {
   return {
     remarkPlugins: pullRequestMarkdownPlugins(detail),
+    rehypePlugins: pullRequestRehypePlugins(detail),
     lineBreaks: sourceControlClients.find(detail?.provider ?? "")?.hardLineBreaks ?? false,
     threadRef,
     repository: detail?.repository ?? null,
diff --git a/apps/web/src/components/pullRequest/PullRequestMarkdown.browser.test.tsx b/apps/web/src/components/pullRequest/PullRequestMarkdown.browser.test.tsx
index fae5270d27123..7dee77bcf2752 100644
--- a/apps/web/src/components/pullRequest/PullRequestMarkdown.browser.test.tsx
+++ b/apps/web/src/components/pullRequest/PullRequestMarkdown.browser.test.tsx
@@ -25,6 +25,7 @@ async function renderBody(
   const { repository = null, text = "first line\nsecond line", ...props } = options;
   const context = {
     remarkPlugins: [],
+    rehypePlugins: [],
     lineBreaks: sourceControlClients.get(host).hardLineBreaks ?? false,
     threadRef: null,
     repository,
diff --git a/apps/web/src/components/pullRequest/PullRequestMarkdown.tsx b/apps/web/src/components/pullRequest/PullRequestMarkdown.tsx
index 449e901d0f0d3..a19c2895692ab 100644
--- a/apps/web/src/components/pullRequest/PullRequestMarkdown.tsx
+++ b/apps/web/src/components/pullRequest/PullRequestMarkdown.tsx
@@ -21,6 +21,8 @@ import { splitPullRequestBody, type PullRequestBodySegment } from "./pullRequest
 export const PullRequestMarkdownContext = createContext<{
   /** Stable per repository, so comments share one renderer and its parse cache. */
   remarkPlugins: PluggableList;
+  /** Stable per change request, whose page its host resolves relative destinations against. */
+  rehypePlugins: PluggableList;
   lineBreaks: boolean;
   threadRef: ScopedThreadRef | null;
   /** The change request's `owner/name`, which can differ from the checkout the body renders in. */
@@ -121,7 +123,9 @@ function PullRequestBodySegmentView({
         threadRef={threadRef}
         pullRequestPanelRef={threadRef ?? PULL_REQUESTS_PANEL_REF}
         environmentId={environmentId}
-        {...(context ? { extraRemarkPlugins: context.remarkPlugins } : {})}
+        {...(context
+          ? { extraRemarkPlugins: context.remarkPlugins, extraRehypePlugins: context.rehypePlugins }
+          : {})}
         lineBreaks={lineBreaks}
         sourceControlMedia
         sourceControlMediaRepository={repository}
diff --git a/apps/web/src/components/pullRequest/guide/GuideProse.tsx b/apps/web/src/components/pullRequest/guide/GuideProse.tsx
index adcdb7cd0a868..2e80b91333018 100644
--- a/apps/web/src/components/pullRequest/guide/GuideProse.tsx
+++ b/apps/web/src/components/pullRequest/guide/GuideProse.tsx
@@ -3,7 +3,7 @@ import { createContext, useContext } from "react";
 
 import { cn } from "~/lib/utils";
 
-import { PullRequestMarkdown } from "../PullRequestMarkdown";
+import { PullRequestMarkdown, PullRequestMarkdownContext } from "../PullRequestMarkdown";
 
 export const GuideProseContext = createContext<{
   readonly environmentId: EnvironmentId;
@@ -20,14 +20,20 @@ export function GuideProse({
   className?: string;
 }) {
   const context = useContext(GuideProseContext);
+  const markdownContext = useContext(PullRequestMarkdownContext);
   if (plain || context === null) return text;
   return (
-    <PullRequestMarkdown
-      text={text}
-      cwd={context.cwd}
-      environmentId={context.environmentId}
-      lineBreaks={false}
-      className={cn("space-y-0 [&_.chat-markdown]:text-inherit", className)}
-    />
+    // The agent writes the guide about the checkout, so its relative links name workspace files.
+    <PullRequestMarkdownContext
+      value={markdownContext === null ? null : { ...markdownContext, rehypePlugins: [] }}
+    >
+      <PullRequestMarkdown
+        text={text}
+        cwd={context.cwd}
+        environmentId={context.environmentId}
+        lineBreaks={false}
+        className={cn("space-y-0 [&_.chat-markdown]:text-inherit", className)}
+      />
+    </PullRequestMarkdownContext>
   );
 }
diff --git a/apps/web/src/components/pullRequest/pullRequestMarkdown.logic.ts b/apps/web/src/components/pullRequest/pullRequestMarkdown.logic.ts
index adf90dbec4e58..1cf07e12ba71f 100644
--- a/apps/web/src/components/pullRequest/pullRequestMarkdown.logic.ts
+++ b/apps/web/src/components/pullRequest/pullRequestMarkdown.logic.ts
@@ -1,4 +1,5 @@
 import {
+  changeRequestLinkResolver,
   changeRequestReferenceAutolinker,
   resolveChangeRequestMediaUrl,
 } from "@t3tools/client-runtime/pull-request-markdown";
@@ -95,3 +96,44 @@ export function pullRequestMarkdownPlugins(
   }
   return plugins;
 }
+
+type HastNode = {
+  type: string;
+  properties?: Record<string, unknown>;
+  children?: HastNode[];
+};
+
+// `dataDarkSrc` and `dataLightSrc` carry a `<picture>`'s theme sources.
+const URL_PROPERTIES = ["href", "src", "poster", "dataDarkSrc", "dataLightSrc"] as const;
+
+// After raw HTML is parsed, so `<img src>` and `<a href>` resolve like markdown's own; code is text.
+function rehypeChangeRequestUrls(options: { readonly resolve: (url: string) => string }) {
+  const visit = (node: HastNode): void => {
+    const properties = node.properties;
+    if (node.type === "element" && properties) {
+      for (const key of URL_PROPERTIES) {
+        const value = properties[key];
+        if (typeof value === "string") properties[key] = options.resolve(value);
+      }
+    }
+    node.children?.forEach(visit);
+  };
+  return (tree: HastNode) => visit(tree);
+}
+
+const changeRequestRehypePlugins = new Map<string, PluggableList>();
+
+/** One list per change request, since its host can resolve destinations against its page. */
+export function pullRequestRehypePlugins(
+  changeRequest: { readonly provider: string; readonly url: string } | null,
+): PluggableList {
+  const resolve = changeRequestLinkResolver(changeRequest);
+  if (changeRequest === null || resolve === null) return NO_PLUGINS;
+  const key = `${changeRequest.provider}\u0000${changeRequest.url}`;
+  let plugins = changeRequestRehypePlugins.get(key);
+  if (plugins === undefined) {
+    plugins = [[rehypeChangeRequestUrls, { resolve }]];
+    changeRequestRehypePlugins.set(key, plugins);
+  }
+  return plugins;
+}
diff --git a/packages/client-runtime/src/pullRequestMarkdown.ts b/packages/client-runtime/src/pullRequestMarkdown.ts
index 2ca59143ad296..b90c03c4ac241 100644
--- a/packages/client-runtime/src/pullRequestMarkdown.ts
+++ b/packages/client-runtime/src/pullRequestMarkdown.ts
@@ -271,6 +271,18 @@ function splitBodyAt(body: string, baseOffset: number): ReadonlyArray<PullReques
   return segments;
 }
 
+/**
+ * Makes absolute a link destination the change request's host writes relative to its page, and
+ * returns any other destination as it is. Null when the host writes none.
+ */
+export function changeRequestLinkResolver(
+  changeRequest: { readonly provider: string; readonly url: string } | null | undefined,
+): ((url: string) => string) | null {
+  if (!changeRequest) return null;
+  const resolve = sourceControlClients.get(changeRequest.provider).resolveRelativeUrl;
+  return resolve === undefined ? null : (url) => resolve(url, changeRequest.url) ?? url;
+}
+
 /**
  * Finds the references the change request's host links in plain text, resolved against the change
  * request's repository. Null when the host links none.
diff --git a/packages/source-control-core/src/shared/definition.ts b/packages/source-control-core/src/shared/definition.ts
index 8f71e1cc73468..60036ea9a13b1 100644
--- a/packages/source-control-core/src/shared/definition.ts
+++ b/packages/source-control-core/src/shared/definition.ts
@@ -290,6 +290,12 @@ export interface SourceControlDefinition {
     text: string,
     repositoryUrl: string,
   ) => ReadonlyArray<ReferenceAutolink>;
+  /**
+   * The absolute URL for a link destination this host's bodies write relative to the change
+   * request's page at `changeRequestUrl`, or null for any other destination. Absent for a host
+   * whose bodies link absolutely.
+   */
+  readonly resolveRelativeUrl?: (url: string, changeRequestUrl: string) => string | null;
   /** True when the host renders a single newline in change request text as a line break. */
   readonly hardLineBreaks?: boolean;
   /** Where the host lists a change request's checks. Absent means the change request's own page. */
diff --git a/packages/source-control-github/src/shared/definition.test.ts b/packages/source-control-github/src/shared/definition.test.ts
index 924ab31716853..1a587b4acf2c0 100644
--- a/packages/source-control-github/src/shared/definition.test.ts
+++ b/packages/source-control-github/src/shared/definition.test.ts
@@ -178,3 +178,29 @@ describe("GitHub media URLs", () => {
     }
   });
 });
+
+describe("GitHub relative URLs", () => {
+  const resolve = (url: string) =>
+    definition.resolveRelativeUrl?.(url, "https://github.com/o/r/pull/5");
+
+  it("resolves a pull request body's relative destinations against the pull request page", () => {
+    expect(resolve("../blob/dd60e3cd/docs/shot.png?raw=true")).toBe(
+      "https://github.com/o/r/blob/dd60e3cd/docs/shot.png?raw=true",
+    );
+    expect(resolve("/other/r/blob/801d91ff/docs/shot.webp?raw=true")).toBe(
+      "https://github.com/other/r/blob/801d91ff/docs/shot.webp?raw=true",
+    );
+    for (const url of [
+      "https://example.com/shot.png",
+      "#x",
+      "README.md",
+      "apps/web/src/x.ts",
+      "docs/shot.png",
+      "mailto:a@example.com",
+      "//evil.example/shot.png",
+      "\\\\evil.example\\shot.png",
+    ]) {
+      expect(resolve(url), url).toBeNull();
+    }
+  });
+});
diff --git a/packages/source-control-github/src/shared/definition.ts b/packages/source-control-github/src/shared/definition.ts
index 3c33cfb3a3f64..69d148f943598 100644
--- a/packages/source-control-github/src/shared/definition.ts
+++ b/packages/source-control-github/src/shared/definition.ts
@@ -44,6 +44,22 @@ function isRepositoryPath(repository: string): boolean {
   );
 }
 
+// The forms GitHub writes against the PR page. Bare paths stay workspace-relative: they 404 there.
+const PAGE_RELATIVE = /^(?:\.\.\/|\/(?![/\\]))/u;
+
+/** As github.com's browser reads a body's destinations: relative to the pull request's page. */
+function resolveRelativeUrl(url: string, changeRequestUrl: string): string | null {
+  if (!PAGE_RELATIVE.test(url)) return null;
+  try {
+    const page = new URL(changeRequestUrl);
+    const resolved = new URL(url, page);
+    // `//host/x`, and the `\\host/x` a browser reads the same way, leave the page's origin.
+    return resolved.origin === page.origin ? resolved.href : null;
+  } catch {
+    return null;
+  }
+}
+
 /** Signing in through the T3 Code for GitHub app lifts the per-user API rate limit to the app's. */
 export const APP_SIGN_IN: SourceControlAppSignIn = {
   appName: "T3 Code for GitHub",
@@ -127,6 +143,7 @@ export const definition = defineSourceControl({
       ? null
       : new URL(`/${encodeURIComponent(login)}`, repositoryUrl).toString(),
   referenceAutolinks: gitHubReferenceAutolinks,
+  resolveRelativeUrl,
   changeRequestChecksUrl: (changeRequestUrl) => `${changeRequestUrl.replace(/\/+$/u, "")}/checks`,
   // Before servers reported their actions, GitHub was the only host they acted on from a list.
   changeRequestActionsWhenUnreported: new Set(["close", "merge", "ready", "reopen"] as const),