Markdown formatting

OpenClaw converts outbound Markdown into a shared intermediate representation (IR) before rendering channel-specific output. The IR keeps plain text plus style/link spans, so one parse step feeds every channel and chunking never splits formatting mid-span.

Pipeline

1. Parse Markdown into IR (markdownToIR) - plain text plus style spans (bold, italic, strikethrough, code, code block, spoiler, blockquote, heading 1-6) and link spans. Offsets are UTF-16 code units so Signal style ranges align with its API directly. Tables parse only when the channel opts into a table mode.
2. Chunk the IR (chunkMarkdownIR / renderMarkdownIRChunksWithinLimit)
   • splitting happens on IR text before rendering, so inline styles and links are sliced per chunk instead of breaking across a boundary.
3. Render per channel (renderMarkdownWithMarkers) - a style-marker map turns spans into the channel's native markup.

IR example

Input Markdown:

Hello **world** - see [docs](https://docs.openclaw.ai).

IR (schematic):

{  "text": "Hello world - see docs.",  "styles": [{ "start": 6, "end": 11, "style": "bold" }],  "links": [{ "start": 19, "end": 23, "href": "https://docs.openclaw.ai" }]}

Table handling

markdown.tables controls how a channel converts Markdown tables, per channel and optionally per account:

Per-channel plugin defaults: Signal, WhatsApp, and Matrix default to bullets; Mattermost defaults to off; Telegram defaults to block (which resolves to code unless the account has richMessages enabled). Any channel without an explicit plugin default falls back to code.

channels:  discord:    markdown:      tables: code    accounts:      work:        markdown:          tables: off

Chunking rules

• Chunk limits come from channel adapters/config and apply to IR text, not rendered output.
• Fenced code blocks are kept as one block with a trailing newline so channels render the closing fence correctly.
• List and blockquote prefixes are part of the IR text, so chunking never splits mid-prefix.
• Inline styles never split across chunks; the renderer reopens an open style at the start of the next chunk.

See Streaming and chunking for chunk-boundary and delivery behavior across channels.

Link policy

• Slack: [label](url) -> <url|label>; bare URLs stay bare.
• Telegram: [label](url) -> <a href="url">label</a> (HTML parse mode).
• Signal: [label](url) -> label (url) unless the label already matches the URL.

Spoilers

Spoiler markers (||spoiler||) are parsed for Signal (mapped to SPOILER style ranges) and Telegram (mapped to <tg-spoiler>). Other channels treat ||...|| as plain text.

Collapsible details

The Control UI and Telegram accounts with richMessages: true render <details><summary>Label</summary> disclosures as native collapsible sections. OpenClaw tells the model about this option only when the current reply surface supports it. Other channels, including Telegram accounts without rich messages, flatten each disclosure to **Summary** followed by the visible body so no content is hidden or lost.

Adding or updating a channel formatter

1. Parse once with markdownToIR(...), passing channel-appropriate options (autolink, headingStyle, blockquotePrefix, tableMode).
2. Render with renderMarkdownWithMarkers(...) and a style-marker map (or custom style-range logic for transports like Signal).
3. Chunk with chunkMarkdownIR(...) or renderMarkdownIRChunksWithinLimit(...) before rendering each chunk.
4. Wire the adapter to call the new chunker and renderer from the outbound send path.
5. Test with format tests plus an outbound delivery test if the channel chunks.

Common gotchas

• Slack angle-bracket tokens (<@U123>, <#C123>, <https://...>) must survive escaping; raw HTML still needs to be escaped safely.
• Telegram HTML requires escaping text outside tags to avoid broken markup.
• Signal style ranges use UTF-16 offsets, not code-point offsets.
• Preserve trailing newlines on fenced code blocks so the closing marker lands on its own line.

Related