[Hona]

Replaces Shiki with @pierre/highlights for all code highlighting in the desktop app: review/file diffs, markdown code blocks and streaming code blocks. Shiki, @shikijs/stream and marked-shiki are no longer used by the GUI (packages/web keeps its own Shiki).

• Diffs: @pierre/diffs 1.5.1 → 1.6.1 (first version with preferredHighlighter: "highlights"). Viewers and both worker pools share one highlightOptions object, so they cannot disagree.
• Markdown: Highlights is synchronous, so createMarkdownParser() highlights fenced code itself with a marked renderer. The injected highlight callback and marked-shiki are gone.
• Streaming: LiveTokenizer replaces ShikiStreamTokenizer. Each delta is one append edit, so only the growing last line is re-lexed.
• Theme: OpenCodeTheme is a Zed palette whose values name the app's --syntax-* variables, so light, dark and custom themes keep working. Token types are grouped the way Pierre's own pierre-dark theme groups them, and each group uses the app syntax role with the same meaning. Colours follow Pierre, not Shiki.
• Cleanup: removed the dead MarkedProvider/useMarked context, marked-theme-register, the unused getWorkerPools/workerFactory exports, and Shiki's bundledLanguagesInfo (attachment labels now use a small extension → name map).
• Fences keep their own language in class="language-…" even without a lexer, so Mermaid and labels still work.

flowchart LR
  subgraph Before
    A1[diffs pool] --> S1[Shiki + Oniguruma wasm + grammars]
    B1[markdown worker] --> S2[Shiki + Oniguruma wasm + grammars]
    C1[MarkedProvider] --> S3[Shiki via pierre shared highlighter]
  end
  subgraph After
    A2[diffs pool] --> H1[Highlights wasm]
    B2[markdown worker] --> H2[Highlights wasm]
  end

Loading

// packages/session-ui/src/pierre/index.ts
registerCustomTheme(OpenCodeTheme.name, () => Promise.resolve(OpenCodeTheme), "zed")
export const highlightOptions = { theme: OpenCodeTheme.name, preferredHighlighter: "highlights" } as const

Benchmarks on real session data

Inputs come from the last 14 days of prod OpenCode Desktop data (91 sessions, 14,085 messages): the largest review-panel diffs rebuilt from turn snapshots (picked from 5,075), files the agent wrote, edit-tool patches, assistant answers and their code blocks. One distinct file type per row.

Each engine runs the same code the app runs (renderDiffWithHighlighter / renderFileWithHighlighter from @pierre/diffs 1.6.1 with the pool's render options, the old vs new markdown parser, and ShikiStreamTokenizer vs LiveTokenizer). Every engine × suite ran in 3 fresh processes with alternating order. Values are medians of warm runs. Bun 1.4.3, Windows.

Surface	Shiki	Highlights	Speedup	Peak RSS (Shiki → Highlights)
Review panel diffs (10 files, 13–535 KiB)	1,820 ms	301 ms	6.1×	1,206 → 417 MiB
File viewer (10 written files)	379 ms	13.3 ms	28.5×	680 → 140 MiB
Edit-tool patches (8)	68.4 ms	4.05 ms	16.9×	284 → 112 MiB
Markdown answers (8)	47.7 ms	7.90 ms	6.0×	240 → 112 MiB
Streaming code blocks (10, 32-char deltas)	23.4 ms	10.7 ms	2.2×	193 → 90 MiB
Time to first highlighter	40–45 ms	8–12 ms	~4×

Per-input results

Review panel diffs

Input	Size	Shiki (ms)	Highlights (ms)	Speedup
session-runner.test.ts	535 KiB	787	131	6.0×
ui.rs	432 KiB	356	90.4	3.9×
index.tsx	262 KiB	359	65.8	5.4×
styles.css	133 KiB	158	6.27	25.1×
SPEC.md	106 KiB	15.1	1.48	10.2×
gpt-nano-reuses-a-cached-prompt.json	105 KiB	0.51	0.21	2.4×
Settings.swift	90 KiB	95.6	3.35	28.5×
publish.yml	63 KiB	18.6	1.11	16.7×
astro.config.mjs	17 KiB	10.5	0.65	16.1×
sdk.js	13 KiB	19.5	0.48	40.6×

File viewer

Input	Size	Shiki (ms)	Highlights (ms)	Speedup
index.html	74 KiB	147	4.45	33.1×
compare.tsx	67 KiB	59.2	2.61	22.7×
settings_window.rs	54 KiB	38.6	2.01	19.2×
v5-tail.js	40 KiB	96.7	2.38	40.6×
SPEC.md	26 KiB	4.87	0.51	9.5×
i18n_new_1.json	24 KiB	4.49	0.25	18.2×
p7_va.ts	20 KiB	4.44	0.16	27.8×
ListenActivity.java	17 KiB	13.8	0.57	24.3×
interface-mode.css	6 KiB	4.48	0.18	25.4×
inventory.py	4 KiB	4.97	0.17	29.3×

Edit-tool patches

Input	Size	Shiki (ms)	Highlights (ms)	Speedup
start.tsx	12 KiB	17.1	1.45	11.8×
ssh.rs	11 KiB	9.40	0.54	17.5×
Program.cs	9 KiB	14.3	0.92	15.5×
v5-tail.js	8 KiB	19.2	0.47	40.7×
AGENTS.md	7 KiB	1.01	0.08	13.4×
host.ts	7 KiB	4.78	0.33	14.7×
ListenActivity.java	3 KiB	2.54	0.22	11.4×
bunfig.toml	3 KiB	0.07	0.05	1.3×

Markdown answers

Input	Size	Shiki (ms)	Highlights (ms)	Speedup
answer 1	33 KiB	21.7	2.35	9.2×
answer 2	20 KiB	9.11	1.62	5.6×
answer 3	17 KiB	4.91	1.28	3.8×
answer 4	16 KiB	5.49	1.25	4.4×
answer 5	11 KiB	3.28	0.43	7.6×
answer 6	10 KiB	1.70	0.62	2.7×
answer 7	4 KiB	1.01	0.07	13.6×
answer 8	4 KiB	0.42	0.28	1.5×

Streaming code blocks

Input	Size	Shiki (ms)	Highlights (ms)	Speedup
markdown	4 KiB	2.97	1.49	2.0×
ts	3 KiB	11.4	1.44	7.9×
rust	2 KiB	4.84	1.39	3.5×
toml	1 KiB	0.52	1.00	0.5×
jsonc	1 KiB	0.29	1.23	0.2×
powershell	1 KiB	1.07	0.74	1.4×
sh	1 KiB	1.14	1.04	1.1×
nsis	<1 KiB	0.31	0.84	0.4×
js	<1 KiB	0.63	0.83	0.8×
mermaid	<1 KiB	0.20	0.69	0.3×

Tiny streamed blocks cost a flat ~0.7 ms more, because each LiveTokenizer gets its own Wasm instance. Large blocks are 2–8× faster.

Bundle (vite build, packages/app/dist)

	Shiki (dev)	Highlights (this PR)
All JS/Wasm/CSS	64.2 MiB / 19.9 MiB gzip	65.2 MiB / 20.3 MiB gzip
Markdown worker loads	458 KiB + 608 KiB Oniguruma + grammars	579 KiB (Wasm inlined)
Diffs worker loads	~255 KiB + 608 KiB Oniguruma + grammars	72 KiB + 269 KiB Highlights

The total grows by 0.4 MiB gzip, mostly from the @pierre/diffs 1.6.1 bump. Shiki's grammar chunks are still emitted (@pierre/diffs imports its Shiki backend lazily) but are never fetched.

Visuals

Real excerpts from the corpus, Shiki (left) and Highlights (right), with the app's resolved theme variables:

Dark	Light

Storybook, dev vs this PR:

	Before	After
Review diff
Markdown

Colours

Pierre decides what each character is: its lexer marks refresh: as a property and Math as a type. The app theme decides the actual colours through --syntax-*. The palette connects the two by following Pierre's own groups, and the colours intentionally differ from Shiki's.

pierre-dark group	Token types	App role
Keywords	keyword.*, preproc, tag, selector	--syntax-keyword
Types	type.*, constructor, enum, JSX components	--syntax-type
Functions	function.*, selector.id	--syntax-primitive
Variables	variable, property, JSON keys	--syntax-variable
Constants	constant.*, number, boolean, escapes, namespace, label	--syntax-constant
Attributes	attribute.*, selector.class	--syntax-property
Operators	operator, keyword.operator	--syntax-operator
Punctuation	punctuation.*	--syntax-punctuation
Strings / regex / comments	string, string.regex, comment.*	--syntax-string / --syntax-regexp / --syntax-comment

Two token types that share a colour in pierre-dark always share a role here. Where Pierre uses a shade the app has no role for, the role of the same colour family is used (numbers and escapes are cyan, like constants).

[Copilot]

Copilot was unable to review this pull request because the user who requested the review has reached their quota limit.

An organization owner can choose the repository organization as the billing source for reviews requested by members with a paid Copilot license. Learn about Copilot code review billing.

[opencode-agent]

I found no problems that should block a merge. Both type checks and the nearest tests pass. I couldn't run the desktop app or Storybook here, so there are no screenshots from me; the ones in the description are the visual evidence.

• Tests and type checks: the marked-parser tests in packages/ui (56) and bun test src in packages/session-ui (252) pass, and typecheck passes in ui, session-ui and app.
• Language names: Highlights accepts the usual short fence names (ts, py, sh, yml, rs, c++, golang, …). Unsupported ones like mermaid are lexed as text but keep their own language-… class.
• Streaming: I replayed the new LiveTokenizer append-edit logic in small deltas over TypeScript containing a block comment and a multi-line template literal. The streamed text matched the source exactly, and every character had the same colour as codeToTokens on the whole block.
• Diffs: rendering through @pierre/diffs 1.6.1 with the zed-registered OpenCodeTheme gives var(--syntax-*) colours, and the large-file pool's tokenizeMaxLineLength is still passed through to the Highlights backend.

Public API is unchanged: only internal workspace modules and exports are removed (MarkedProvider/useMarked, marked-theme, getWorkerPools, workerFactory), and nothing in the SDK, server, plugins, config or CLI is touched.

No further concerns.

Fixes #57876