​

Diffs

• before and after text
• a unified patch

• a gateway viewer URL for canvas presentation
• a rendered file path (PNG or PDF) for message delivery
• both outputs in one call

​

Quick start

1. Enable the plugin.
2. Call diffs with mode: "view" for canvas-first flows.
3. Call diffs with mode: "file" for chat file delivery flows.
4. Call diffs with mode: "both" when you need both artifacts.

​

Enable the plugin

{
  plugins: {
    entries: {
      diffs: {
        enabled: true,
      },
    },
  },
}

​

Disable built-in system guidance

{
  plugins: {
    entries: {
      diffs: {
        enabled: true,
        hooks: {
          allowPromptInjection: false,
        },
      },
    },
  },
}

​

Typical agent workflow

1. Agent calls diffs.
2. Agent reads details fields.
3. Agent either:
   • opens details.viewerUrl with canvas present
   • sends details.filePath with message using path or filePath
   • does both

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Input examples

{
  "before": "# Hello\n\nOne",
  "after": "# Hello\n\nTwo",
  "path": "docs/example.md",
  "mode": "view"
}

{
  "patch": "diff --git a/src/example.ts b/src/example.ts\n--- a/src/example.ts\n+++ b/src/example.ts\n@@ -1 +1 @@\n-const x = 1;\n+const x = 2;\n",
  "mode": "both"
}

​

Tool input reference

• before (string): original text. Required with after when patch is omitted.
• after (string): updated text. Required with before when patch is omitted.
• patch (string): unified diff text. Mutually exclusive with before and after.
• path (string): display filename for before and after mode.
• lang (string): language override hint for before and after mode.
• title (string): viewer title override.
• mode ("view" | "file" | "both"): output mode. Defaults to plugin default defaults.mode. Deprecated alias: "image" behaves like "file" and is still accepted for backward compatibility.
• theme ("light" | "dark"): viewer theme. Defaults to plugin default defaults.theme.
• layout ("unified" | "split"): diff layout. Defaults to plugin default defaults.layout.
• expandUnchanged (boolean): expand unchanged sections when full context is available. Per-call option only (not a plugin default key).
• fileFormat ("png" | "pdf"): rendered file format. Defaults to plugin default defaults.fileFormat.
• fileQuality ("standard" | "hq" | "print"): quality preset for PNG or PDF rendering.
• fileScale (number): device scale override (1-4).
• fileMaxWidth (number): max render width in CSS pixels (640-2400).
• ttlSeconds (number): viewer artifact TTL in seconds. Default 1800, max 21600.
• baseUrl (string): viewer URL origin override. Must be http or https, no query/hash.

• before and after each max 512 KiB.
• patch max 2 MiB.
• path max 2048 bytes.
• lang max 128 bytes.
• title max 1024 bytes.
• Patch complexity cap: max 128 files and 120000 total lines.
• patch and before or after together are rejected.
• Rendered file safety limits (apply to PNG and PDF):
  • fileQuality: "standard": max 8 MP (8,000,000 rendered pixels).
  • fileQuality: "hq": max 14 MP (14,000,000 rendered pixels).
  • fileQuality: "print": max 24 MP (24,000,000 rendered pixels).
  • PDF also has a max of 50 pages.

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Output details contract

• artifactId
• viewerUrl
• viewerPath
• title
• expiresAt
• inputKind
• fileCount
• mode
• context (agentId, sessionId, messageChannel, agentAccountId when available)

• artifactId
• expiresAt
• filePath
• path (same value as filePath, for message tool compatibility)
• fileBytes
• fileFormat
• fileQuality
• fileScale
• fileMaxWidth

• mode: "view": viewer fields only.
• mode: "file": file fields only, no viewer artifact.
• mode: "both": viewer fields plus file fields. If file rendering fails, viewer still returns with fileError.

​

Collapsed unchanged sections

• The viewer can show rows like N unmodified lines.
• Expand controls on those rows are conditional and not guaranteed for every input kind.
• Expand controls appear when the rendered diff has expandable context data, which is typical for before and after input.
• For many unified patch inputs, omitted context bodies are not available in the parsed patch hunks, so the row can appear without expand controls. This is expected behavior.
• expandUnchanged applies only when expandable context exists.

​

Plugin defaults

{
  plugins: {
    entries: {
      diffs: {
        enabled: true,
        config: {
          defaults: {
            fontFamily: "Fira Code",
            fontSize: 15,
            lineSpacing: 1.6,
            layout: "unified",
            showLineNumbers: true,
            diffIndicators: "bars",
            wordWrap: true,
            background: true,
            theme: "dark",
            fileFormat: "png",
            fileQuality: "standard",
            fileScale: 2,
            fileMaxWidth: 960,
            mode: "both",
          },
        },
      },
    },
  },
}

• fontFamily
• fontSize
• lineSpacing
• layout
• showLineNumbers
• diffIndicators
• wordWrap
• background
• theme
• fileFormat
• fileQuality
• fileScale
• fileMaxWidth
• mode

​

Security config

• security.allowRemoteViewer (boolean, default false)
  • false: non-loopback requests to viewer routes are denied.
  • true: remote viewers are allowed if tokenized path is valid.

{
  plugins: {
    entries: {
      diffs: {
        enabled: true,
        config: {
          security: {
            allowRemoteViewer: false,
          },
        },
      },
    },
  },
}

​

Artifact lifecycle and storage

• Artifacts are stored under the temp subfolder: $TMPDIR/openclaw-diffs.
• Viewer artifact metadata contains:
  • random artifact ID (20 hex chars)
  • random token (48 hex chars)
  • createdAt and expiresAt
  • stored viewer.html path
• Default viewer TTL is 30 minutes when not specified.
• Maximum accepted viewer TTL is 6 hours.
• Cleanup runs opportunistically after artifact creation.
• Expired artifacts are deleted.
• Fallback cleanup removes stale folders older than 24 hours when metadata is missing.

​

Viewer URL and network behavior

• /plugins/diffs/view/{artifactId}/{token}

• /plugins/diffs/assets/viewer.js
• /plugins/diffs/assets/viewer-runtime.js

• If baseUrl is provided, it is used after strict validation.
• Without baseUrl, viewer URL defaults to loopback 127.0.0.1.
• If gateway bind mode is custom and gateway.customBindHost is set, that host is used.

• Must be http:// or https://.
• Query and hash are rejected.
• Origin plus optional base path is allowed.

​

Security model

• Loopback-only by default.
• Tokenized viewer paths with strict ID and token validation.
• Viewer response CSP:
  • default-src 'none'
  • scripts and assets only from self
  • no outbound connect-src
• Remote miss throttling when remote access is enabled:
  • 40 failures per 60 seconds
  • 60 second lockout (429 Too Many Requests)

• Screenshot browser request routing is deny-by-default.
• Only local viewer assets from http://127.0.0.1/plugins/diffs/assets/* are allowed.
• External network requests are blocked.

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Browser requirements for file mode

1. browser.executablePath in OpenClaw config.
2. Environment variables:
   • OPENCLAW_BROWSER_EXECUTABLE_PATH
   • BROWSER_EXECUTABLE_PATH
   • PLAYWRIGHT_CHROMIUM_EXECUTABLE_PATH
3. Platform command/path discovery fallback.

• Diff PNG/PDF rendering requires a Chromium-compatible browser...

​

Troubleshooting

• Provide patch or both before and after text.
  • Include both before and after, or provide patch.
• Provide either patch or before/after input, not both.
  • Do not mix input modes.
• Invalid baseUrl: ...
  • Use http(s) origin with optional path, no query/hash.
• {field} exceeds maximum size (...)
  • Reduce payload size.
• Large patch rejection
  • Reduce patch file count or total lines.

• Viewer URL resolves to 127.0.0.1 by default.
• For remote access scenarios, either:
  • pass baseUrl per tool call, or
  • use gateway.bind=custom and gateway.customBindHost
• Enable security.allowRemoteViewer only when you intend external viewer access.

• This can happen for patch input when the patch does not carry expandable context.
• This is expected and does not indicate a viewer failure.

• Artifact expired due TTL.
• Token or path changed.
• Cleanup removed stale data.

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Operational guidance

• Prefer mode: "view" for local interactive reviews in canvas.
• Prefer mode: "file" for outbound chat channels that need an attachment.
• Keep allowRemoteViewer disabled unless your deployment requires remote viewer URLs.
• Set explicit short ttlSeconds for sensitive diffs.
• Avoid sending secrets in diff input when not required.
• If your channel compresses images aggressively (for example Telegram or WhatsApp), prefer PDF output (fileFormat: "pdf").

• Powered by Diffs.

​

Related docs

• Tools overview
• Plugins
• Browser