diffs

When you need to show edits as a real diff, prefer the `diffs` tool instead of writing a manual summary. The `diffs` tool accepts either `before` + `after` text, or a unified `patch` string. Check `details.changed`: identical before/after input returns `false` without creating an artifact; rendered results return `true`. Use `mode=view` when you want an interactive gateway-hosted viewer. After the tool returns, present `details.viewerUrl` with an available surface-presentation tool. If the deployment uses a loopback trusted proxy (for example Tailscale Serve with `gateway.trustedProxies` including `127.0.0.1`), raw loopback viewer requests can fail closed without forwarded client-IP headers. In that topology, prefer `mode=file` / `mode=both`, or use a configured `viewerBaseUrl` / explicit proxy/public `baseUrl` when you need a shareable viewer URL. Use `mode=file` when you need a rendered file artifact. Set `fileFormat=png` (default) or `fileFormat=pdf`. The tool result includes `details.filePath`. For large or high-fidelity files, use `fileQuality` (`standard`|`hq`|`print`) and optionally override `fileScale`/`fileMaxWidth`. When you need to deliver the rendered file to a user or channel, do not rely on the raw tool-result renderer. Instead, use an available file-sending tool to send `details.filePath` as an attachment. Use `mode=both` when you want both the gateway viewer URL and the rendered artifact. If the user has configured diffs plugin defaults, prefer omitting `mode`, `theme`, `layout`, and related presentation options unless you need to override them for this specific diff. Include `path` for before/after text when you know the file name.