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SideButton MCP Server ​

Open source platform for AI agents with structured roles, skills, and domain knowledge.

The AI Agent Stack — SideButton

What is SideButton? ​

SideButton is an open-source platform that packages domain knowledge for AI agents. Install knowledge packs for web apps, automate with YAML workflows, and give AI agents real browser control via MCP.

  • Install knowledge packs — pre-built bundles of domain knowledge, workflows, and role playbooks for specific web apps
  • Define reusable workflows in YAML with 46 step types (browser, shell, LLM, issues, git, control flow)
  • Orchestrate cloud agents — chain workflows into playbooks that work tickets end-to-end behind verdict gates
  • Connect AI agents via MCP — Claude Code, Cursor, or any MCP client gets real browser control
  • Extend with plugins — add custom MCP tools in any language (bash, Node.js, Python)

Latest release — Screenshot Capture Comes to Workflows and MCP ​

2026-08-27 · workflow & MCP release · all release posts

A workflow or an MCP client can now write a screenshot straight to a file — cropped, redacted, and never seen by the agent's own context.

Screenshots straight from a workflow or MCP call ​

The new browser.screenshot step captures the page — or a selector / ref / region crop of it — and writes a PNG to a file on the machine running SideButton, returning only the path it wrote. The screenshot MCP tool gained the same path option: pass it and the tool writes the file instead of returning image bytes; leave it out and nothing changes for existing callers. A bundled docs_screenshot workflow wires the whole sequence together as a ready-made recipe. Step types now number 46 (43 implemented).

Redact before the pixel is captured ​

The new inject_css MCP tool injects a CSS rule into the page — the main use is blurring or hiding sensitive elements right before a screenshot, so no unredacted image ever exists. Both tools are batchable, so a single browser_batch call can navigate, blur the sensitive selectors, wait, and screenshot-to-file in one round trip. A that never got a value now fails the step loudly instead of being treated as a literal string — previously a missing redaction value silently styled nothing, and the run reported success over an unredacted shot.

Nothing escapes the sandbox ​

Every path either tool writes is contained to the home directory of the user running SideButton — .. traversal and symlinks that escape it are rejected, matching the rule publish_artifact already enforces. publish_artifact now also expands a leading ~/, so a path a screenshot step just wrote can be published verbatim.

→ Read the full post · self-hosted releases: SideButton 1.5.5 · Changelog

Next Steps ​