Heystack

dev.heystackPublished by heystack.devOfficial publisherv0.1.0Updated Oct 24, 2026

Observability for AI apps: investigate traces, logs, LLM usage, replays and crashes; manage alerts.

VerifiedStreamable HTTPWeb executableDeveloper ToolsSecurity & MonitoringAI & ML

Overview

AI-generated overview

Heystack's hosted MCP server lets an assistant investigate AI app traces, logs, crashes and LLM usage, and manage apps, alerts and workspace settings.

What you can do
  • Check app health and open a one-call incident dossier for an investigation
  • Search traces and logs in plain English, open and explain traces, session stories and replays
  • Review issues and crashes with the suspect release, plus gen-AI usage and cost
  • Manage apps, ingest keys, sampling and replay configuration, alert rules and app care
  • Opt-in toolsets add team administration (members, invites, access tokens, audit) and read-only SQL
When to use it
Useful when you want a coding agent to debug why an endpoint or feature is failing after a deploy, review LLM usage and cost, or set up and verify Heystack instrumentation in a project without leaving the editor.
Requirements
Remote streamable HTTP endpoint at mcp.heystack.dev; no local package. Sign-in is OAuth with Heystack (choose an organization); alternatively an Authorization header carrying a Heystack personal access token. Team and SQL toolsets require editing the connection URL.
Before you install
The server can change workspace state: creating apps and ingest keys, editing sampling, replay and alert rules, and team administration such as invites and access tokens. The README says access-granting, key-minting and external-URL actions ask for confirmation, but review before approving. The optional timeline plugin sends edit file paths and one-line command descriptions to Heystack when enabled.

Installation

In SourceWeft

  1. Open Heystack in the dashboard and add it to a workspace.
  2. Connect the required credentials. They are stored privately and never shown on public pages.
  3. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/dev.heystack%2Fheystack/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config. The client completes OAuth sign-in on first connect.

{
  "mcpServers": {
    "heystack": {
      "type": "http",
      "url": "https://mcp.heystack.dev/mcp"
    }
  }
}

README

Heystack plugins

Plugins for Heystack — observability + security for AI apps — so your coding agent can set up Heystack, investigate incidents, and manage your workspace from your editor.

Install (Claude Code)

/plugin marketplace add heystack-hq/heystack-plugins/plugin install heystack@heystack

Then run /mcp to sign in with Heystack and pick your organization. Try: "list my Heystack apps", "why is /checkout failing since the last deploy?", or "set up Heystack in this project and verify it's receiving data".

What you get

heystack (recommended) — the all-in-one plugin:

  • Hosted MCP server at https://mcp.heystack.dev/mcp (connected with ?toolsets=core,manage): app health, search traces & logs in plain English, open and explain traces, session stories and replays, issues and crashes with the suspect release, gen-AI usage & cost, a one-call incident dossier (heystack_investigate); plus apps, ingest keys, sampling/replay config, alert rules and app care. Team administration (members, invites, access tokens, audit) and read-only SQL stay opt-in: edit the plugin's .mcp.json URL to ?toolsets=core,manage,team (or advanced). Actions that grant access, mint keys or tokens, or send data to an external URL always ask for your confirmation. Sign in with Heystack (OAuth) — no keys to paste. Full reference: https://heystack.dev/docs/mcp
  • heystack-setup skill — detects the runtime (Next.js, Cloudflare Workers/Agents, Node, browser, Android) and wires the correct @heystack/otel entry or OTLP path; with the MCP server it creates the app and key itself and verifies data arrives with heystack_verify_setup.
  • heystack-investigate skill — the investigation loop: overview → dossier → traces/sessions → fix in code → verify; when to change issue status or create alerts; never destructive without your confirmation.

heystack-setup — the setup skill on its own (no MCP server), kept for existing installs: /plugin install heystack-setup@heystack.

heystack-timeline (optional, requires heystack) — /plugin install heystack-timeline@heystack. Hooks that show your coding agent's steps on the Heystack investigation timeline.

  • Opt-in: nothing is recorded until you switch on Show my coding-agent steps in the Heystack console (Settings, Profile). Turning it off deletes the recorded steps.
  • Privacy: only the file path of an edit and the one-line description of a shell command are sent. Never file contents, diffs, command lines, prompts or tool output. Absolute paths transit TLS to Heystack and are reduced to repo-relative paths before storage; paths outside the project are dropped.
  • Best-effort: Claude Code gives session-end hooks about 1.5 seconds, so the closing call may not land; the investigation then just goes idle. A shell command without a description records no step.
  • Requires write access on your Heystack connection; it reuses the heystack plugin's MCP sign-in.

Other agents

Layout

.claude-plugin/marketplace.json           # Claude Code marketplace (plugins: heystack, heystack-setup, heystack-timeline)plugins/heystack/                         # all-in-one: .mcp.json + skills/plugins/heystack-setup/                   # skill-only (legacy)plugins/heystack-timeline/                # optional hooks: edit paths + command purposesplugin.json · mcp.json · skills/          # Agent Plugins (cross-vendor) layout of the `heystack` plugin

Source of truth for the skills is the heystack monorepo (packages/setup-skill, packages/investigate-skill); this repo is a mirror.

Source: README.md at commit d20379f

Tools

0
This server asks you to sign in, so SourceWeft could not read its tools without an account and has not indexed them. What a connected account sees can depend on that account and its permissions.

Version history

1
  1. v0.1.0LatestSep 17, 2026

Score

75% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listed15 pts

    Answer tools/list without a credential, or ship a package that starts in a sandbox without one.

  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts

    Declare a license in the repository or the registry entry.