feat(web): a prose mention of a produced file opens it

The chatFileMentions service (provided by ui-deliverables beside its
turn-tail entry, reached via ctx.get) resolves inline-code tokens in the
closing message against the turn's produced locations: exact path or
unique basename links, ambiguity and unknowns stay inert. MarkdownText
gains the optional fileMentions seam — settled renders only, never
inside anchors.

packages/client/ui-primitives/src/index.ts

@@ -40,7 +40,7 @@ export { CodeBlock } from './markdown/CodeBlock.tsx'
 export type { CodeBlockProps } from './markdown/CodeBlock.tsx'
 export { JsonBlock } from './markdown/JsonBlock.tsx'
 export { MarkdownText } from './markdown/MarkdownText.tsx'
-export type { MarkdownCodeLabels } from './markdown/MarkdownText.tsx'
+export type { MarkdownCodeLabels, MarkdownFileMentions } from './markdown/MarkdownText.tsx'
 export { MessageText } from './markdown/MessageText.tsx'
 export { extractMarkdownPlainText } from './markdown/plain-text.ts'
 export type { MarkdownPlainTextMode, MarkdownPlainTextOptions } from './markdown/plain-text.ts'

packages/client/ui-primitives/src/markdown/MarkdownText.module.css

@@ -241,3 +241,23 @@
   background: var(--dsw-alias-bg-base);
   object-fit: contain;
 }
+
+/* Inline file mention: a real file named in prose is the same affordance as a
+   tool row's path link, so it reads the same — underlined at rest. */
+.fileMention {
+  margin: 0;
+  padding: 0;
+  border: none;
+  background: none;
+  font: inherit;
+  color: var(--dsw-alias-label-secondary);
+  text-decoration: underline;
+  text-decoration-color: var(--dsw-alias-label-quaternary);
+  text-underline-offset: 3px;
+  cursor: pointer;
+}
+
+.fileMention:hover {
+  color: var(--dsw-alias-label-primary);
+  text-decoration-color: currentColor;
+}

packages/client/ui-primitives/src/markdown/MarkdownText.tsx

@@ -19,20 +19,25 @@ import {
   collectReferenceTargets, createReferenceTargets, renderBlocks, renderFootnoteSection,
   wrapBlockChildren,
 } from './render.tsx'
-import type { MarkdownCodeLabels, MarkdownRenderContext, ReferenceTargets } from './render.tsx'
+import type { MarkdownCodeLabels, MarkdownFileMentions, MarkdownRenderContext, ReferenceTargets } from './render.tsx'
 import 'katex/dist/katex.min.css'
 import css from './MarkdownText.module.css'
 
-export type { MarkdownCodeLabels } from './render.tsx'
+export type { MarkdownCodeLabels, MarkdownFileMentions } from './render.tsx'
 
 /** One settled full render: parse with math, resolve references, append the footnote section. */
-function renderSettled(text: string, codeLabels: MarkdownCodeLabels | undefined): ReactNode[] {
+function renderSettled(
+  text: string,
+  codeLabels: MarkdownCodeLabels | undefined,
+  fileMentions: MarkdownFileMentions | undefined,
+): ReactNode[] {
   const root = parseGfmWithMath(text)
   const targets = createReferenceTargets()
   collectReferenceTargets(root.children, targets)
   const context: MarkdownRenderContext = {
     streaming: false,
     codeLabels,
+    fileMentions,
     targets,
     footnoteOrder: [],
     footnoteCounts: new Map(),
@@ -96,6 +101,7 @@ class StreamingRenderer {
       const frozenContext: MarkdownRenderContext = {
         streaming: true,
         codeLabels: this.codeLabels,
+        fileMentions: undefined,
         targets: frameTargets,
         footnoteOrder: this.frozenFootnoteOrder,
         footnoteCounts: this.frozenFootnoteCounts,
@@ -113,6 +119,7 @@ class StreamingRenderer {
     const tailContext: MarkdownRenderContext = {
       streaming: true,
       codeLabels: this.codeLabels,
+      fileMentions: undefined,
       targets: frameTargets,
       footnoteOrder: [...this.frozenFootnoteOrder],
       footnoteCounts: new Map(this.frozenFootnoteCounts),
@@ -137,28 +144,33 @@ class StreamingRenderer {
  * the finalize swap) and parses incrementally across chunks; `codeLabels`
  * forwards localized copy-button labels to fence CodeBlocks — pass a
  * reference-stable object (memoized per locale revision), because a new
- * identity discards the streaming render cache mid-message.
+ * identity discards the streaming render cache mid-message. `fileMentions`
+ * links inline-code tokens its resolver recognizes as real files; this is
+ * the single streaming gate — it applies to settled renders only, because a
+ * streaming message's vocabulary is not final and frozen cached elements
+ * must not bake in handlers that could go stale.
  * @returns A GFM document with TeX math rendered through KaTeX; raw HTML,
  * relative links, and unsafe protocols are disabled, while absolute HTTP(S)
  * images render directly.
  */
-export const MarkdownText = memo(function MarkdownText({ text, streaming = false, codeLabels }: {
+export const MarkdownText = memo(function MarkdownText({ text, streaming = false, codeLabels, fileMentions }: {
   text: string
   streaming?: boolean
   codeLabels?: MarkdownCodeLabels | undefined
+  fileMentions?: MarkdownFileMentions | undefined
 }) {
   const streamRef = useRef<StreamingRenderer | null>(null)
   const streamLabelsRef = useRef<MarkdownCodeLabels | undefined>(codeLabels)
   const children = useMemo(() => {
     if (!streaming) {
       streamRef.current = null
-      return renderSettled(text, codeLabels)
+      return renderSettled(text, codeLabels, fileMentions)
     }
     if (streamRef.current === null || streamLabelsRef.current !== codeLabels) {
       streamRef.current = new StreamingRenderer(codeLabels)
       streamLabelsRef.current = codeLabels
     }
     return streamRef.current.render(text)
-  }, [text, streaming, codeLabels])
+  }, [text, streaming, codeLabels, fileMentions])
   return <div className={css.markdown}>{children}</div>
 })

packages/client/ui-primitives/src/markdown/render.tsx

@@ -99,6 +99,21 @@ export function collectReferenceTargets(
   }
 }
 
+/**
+ * File-mention affordance for inline code: the owner resolves an authored
+ * token to the file it names, using its own vocabulary of real files — the
+ * renderer never guesses at what looks like a path.
+ */
+export interface MarkdownFileMentions {
+  /**
+   * Resolve one inline-code token.
+   * @param value - The authored token, exactly as written.
+   * @returns The opener with its accessible label and full-path title, or
+   * undefined when the token names no known file — it then stays inert code.
+   */
+  resolve(value: string): { open: () => void; label: string; title: string } | undefined
+}
+
 /**
  * One render pass's state: immutable options and targets plus the footnote
  * numbering accumulated in document order while references render.
@@ -108,6 +123,10 @@ export interface MarkdownRenderContext {
   readonly streaming: boolean
   /** Localized fence copy-button labels. */
   readonly codeLabels: MarkdownCodeLabels | undefined
+  /** Inline-code file mentions; absent wherever no opener vocabulary exists. */
+  readonly fileMentions: MarkdownFileMentions | undefined
+  /** Inside an anchor's children: interactive mentions must not nest there. */
+  readonly inLink?: boolean
   /** Reference targets visible to this pass. */
   readonly targets: ReferenceTargets
   /** Footnote identifiers in first-reference order; a footnote's number is its 1-based index here. */
@@ -217,7 +236,27 @@ function renderNode(node: Md.RootContent, key: Key, context: MarkdownRenderConte
       // authored text, not a parsed destination, so no normalizeUri: port,
       // path, and query render unchanged.
       const href = inlineCodeHttpUrl(value)
-      return <code key={key}>{href === undefined ? value : renderSafeLink(href, [value], 'link')}</code>
+      if (href !== undefined) return <code key={key}>{renderSafeLink(href, [value], 'link')}</code>
+      // A token the owner's file-mention vocabulary recognizes opens that
+      // file; the resolver, not this renderer, decides what names a file.
+      // Inside an anchor the token stays inert — a button cannot nest there.
+      const mention = context.inLink === true ? undefined : context.fileMentions?.resolve(value)
+      if (mention !== undefined) {
+        return (
+          <code key={key}>
+            <button
+              type="button"
+              className={css.fileMention}
+              title={mention.title}
+              aria-label={mention.label}
+              onClick={mention.open}
+            >
+              {value}
+            </button>
+          </code>
+        )
+      }
+      return <code key={key}>{value}</code>
     }
     case 'html':
       // No HTML parser enters the pipeline: raw HTML stays literal text.
@@ -236,7 +275,7 @@ function renderNode(node: Md.RootContent, key: Key, context: MarkdownRenderConte
     case 'table':
       return renderTable(node, key, context)
     case 'link':
-      return renderAnchor(node.url, renderChildren(node.children, context), key)
+      return renderAnchor(node.url, renderChildren(node.children, { ...context, inLink: true }), key)
     case 'linkReference':
       return renderLinkReference(node, key, context)
     case 'image':
@@ -460,14 +499,14 @@ function renderLinkReference(
   context: MarkdownRenderContext,
 ): ReactNode {
   const definition = context.targets.definitions.get(node.identifier.toUpperCase())
-  const children = renderChildren(node.children, context)
   if (definition === undefined) {
     // The grammar only emits references whose definitions exist somewhere in
     // the same parse, but incremental segments and hand-built trees may still
-    // present unresolved ones: revert to the bracketed source text.
-    return <Fragment key={key}>{'['}{children}{referenceSuffix(node)}</Fragment>
+    // present unresolved ones: revert to the bracketed source text — which is
+    // not an anchor, so mentions inside it stay live.
+    return <Fragment key={key}>{'['}{renderChildren(node.children, context)}{referenceSuffix(node)}</Fragment>
   }
-  return renderAnchor(definition.url, children, key)
+  return renderAnchor(definition.url, renderChildren(node.children, { ...context, inLink: true }), key)
 }
 
 function renderImageReference(