Coding Agent

ask-coding-harness — a general-purpose coding agent in the browser, built on the ask-rb ecosystem. Install it, point it at any project, and the agent fires away: reading, writing, and running commands while you watch every tool call live, approve what needs approving, and review the diffs.

No file tree, no IDE chrome — like the Codex desktop app, the harness gives the agent full access to your project and gets out of the way.

Quick start 

gem install ask-coding-harness

cd /path/to/your/project
ask-coding-harness          # or: ach serve

Open http://localhost:8080. The harness runs the ask-agent loop in-process with the shell toolset (bash, read, write, edit, grep, glob, code, apply_patch) — all routed through ask-sandbox-providers. Set a model via ACH_MODEL (or ASK_AGENT_MODEL) and an API key for the provider (e.g. OPENCODE_API_KEY); the ask-auth chain also reads ~/.ask/credentials.yml.

No API key yet? Try the scripted demo agent — a realistic turn with todos, tool calls, diffs, and an approval flow, no keys needed:

ach demo

What you get

  • The agent, unleashed — ask-agent runs the loop in-process with the full shell toolset, sandboxed via ask-sandbox-providers.
  • Live event stream — text deltas, thinking, tool calls, todos, and plan proposals stream to the browser over SSE as they happen.
  • Approvals — mutating tools (bash, write, edit, …) queue for your approval by default; approve, reject, or approve-all from the UI.
  • Plan mode — opt in with ACH_PLAN_MODE=1: the agent researches read-only, proposes a plan, and only executes after you approve it.
  • Conversations — saved to SQLite, resumable, renameable, archivable.
  • PWA — installable on desktop and mobile; the shell works offline.
  • Extensible — other coding agents (Codex, Claude Code, ACP-based) plug in via ask-coding-providers by setting ACH_ADAPTER.
Page What’s covered
Using the web app Approvals, plan mode, conversations, mobile
The ach CLI ach serve, ach demo, ach run, headless dogfooding
Configuration Environment variables, adapters, programmatic API
Architecture How it fits the ask-rb ecosystem, event schema, extending

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