Loopback MCP server

by joshidikshant·io.github.joshidikshant/loopback·v0.9.4

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Feedback bus for coding agents: pin feedback on the app you're building; a fix turns the pin green

A88/100grade A

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Safety scan

A88/100

full report

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0 stars35 downloads/wk

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If you have run it, two minutes of your experience saves the next person an afternoon.

Loopback tools (10, 3 write)

write = sends, deletes, buys or posts

Read from the package source without running it. The installed server may list more.

loopback_add_comment
Append a comment to a feedback item's discussion trail. Use for investigation notes, questions back to the reporter, or reasoning worth preserving. Args: id, author, body (markdown ok).
loopback_claim_feedback
Atomically claim a feedback item for an agent before working on it. Prevents two agents from fixing the same thing. Args: id, agent (your name, e.g. 'claude-code', 'codex', 'gemini'), force (default false). On success the item's assignee_agent is set and status moves to 'in_progress' (from open/triaged). If another agent already holds the claim, this fails with a message naming the holder — pass f
loopback_get_feedback
Fetch one feedback item with full context: description, repro steps, console lines, network entries, screenshot/replay links, linked change (commit/PR), and the complete comment trail. Args: id (fb_...), response_format (markdown|json). Read this before starting a fix — it contains everything captured at report time.
loopback_get_stats
Overview of the feedback queue: counts by project and status. Use to orient before picking work, or to report queue health. Args: project (optional — omit for all projects). Returns { total, projects: [{ project, by_status, total }] }.
loopback_link_change
Attach the fix to a feedback item so the loop is auditable: which repo/branch/commit/PR addressed it and a one-paragraph diff summary. Args: id, plus any of repo, branch, commit, pr_url, diff_summary. Provided fields merge into existing links. Call this right after committing the fix, before updating status to 'fixed'.
loopback_list_feedback
List feedback items, filtered and paginated. This is the entry point for "work the queue". Args (all optional): project, status (open|triaged|in_progress|fixed|verified|wontfix), type (ui|backend|usage|ux), severity (p0-p3), source, assignee_agent, limit (default 20), offset (default 0), response_format (markdown|json). Returns items ordered most-severe first, then newest. Pagination metadata: tot
loopback_resolve_feedback
Close a feedback item with a final outcome. Args: id, resolution ('verified' = the fix was confirmed against the running app, tests, or the relevant metric/replay; 'wontfix' = intentionally not addressing), note (optional closing comment), agent (YOUR name — this is the write that turns the reporter's pin full green, and omitting it records the generic default instead of you). Prefer verifying bef
loopback_submit_feedbackwrite action
Create a new feedback item in the Loopback bus. Use this to file any observation about a running product: a UI defect, a backend error, a usage insight, or a UX papercut. Every item is tagged to a project so the right agent picks it up later. Args: project (slug), type (ui|backend|usage|ux), title, and optionally body, severity (p0-p3, default p2), source, reporter, route, url, dom_selector, scree
loopback_update_feedbackwrite action
loopback_update_statuswrite action
Move a feedback item through the workflow: open → triaged → in_progress → fixed → verified | wontfix. Args: id, status, note (optional — recorded as a comment for the audit trail), author (default 'agent'). Use 'fixed' after making the change; use loopback_resolve_feedback for final verified/wontfix closure.

Public scan report

scanner v0.1.9 · 2026-09-24 · same rubric, same numbers if you re-run it

no findings

Code scan17 source files scanned25/25
–Live reliabilityno gateway calls yet and no remote to proben/a
–Tool poisoningtools not inspected (local package is not executed); not countedn/a
Auth qualitylocal package, no credentials required12/15
Maintenancelast push 53 days ago12/15
Maintainer identityregistry namespace matches repository owner; GitHub account older than a year8/10

Overall 88/100. Components that don't apply are left out of the denominator. Any critical finding is an F.Rubric Appeal a finding JSON

How Loopback compares

Against every graded MCP server, from our own scans and uptime checks. Updated after each scan run.

Safety score: 88/100; higher than 75% of 48,255 servers
Tools: 10; the typical server has 7
Tools that change things: 30%; typical: 0%. Fewer write tools means less an agent can break
Downloads a week: 35; more than 25% of 12,191 servers with a package

What its tools let an agent do: 7 read · 3 change

Install Loopback in Claude Code, Cursor or VS Code

Runs npx -y loopback-mcp-server on your machine. Read the scan report first; the gateway never runs local packages.

claude mcp add loopback -- npx -y loopback-mcp-server

Add to Cursor

What the publisher says

From the Loopback repository's README, as published. We do not edit it. Read it on GitHub

Loopback

Pin feedback on the app you're building. Any coding agent claims it. The pin turns green when the fix is verified.

Loopback is the interactive feedback layer between real product usage and your coding agents: one script tag makes the app you're running locally commentable (Vercel-toolbar-style toolbar, element-anchored pins; deployed public sites go via the /ingest rails instead — see surface compatibility), every pin auto-captures the functional context — failing requests with response bodies, console trail, the route journey that led there, LLM run metadata, typed repro steps — and lands in one project-tagged queue that Claude Code, Codex, and Gemini CLI all work over MCP. When an agent's fix is verified, the pin turns green on the page, live.

https://github.com/user-attachments/assets/1e1b2f9f-0130-4b1d-a0dd-3aff8d801d5a

![The loop, closed: a green verified pin on the form claude-code fixed (PR linked), an amber open pin on the AI answer, and the Loopback panel listing both]

Seeded demo capture (generated by scripts/screenshot.mjs): the contact form's backend bug pinned, claimed by claude-code, marked fixed with a linked change, verified — pin and badge green. The wrong AI answer is still amber/open.

Why

Coding agents can fix anything you can describe — but the loop back from real usage is missing. You notice a broken flow, screenshot it, re-describe it in a prompt, paste console output, explain which project it belongs to. Every time, for every agent. Vercel's comments have no public API; Claude Design's anchored comments are artifact-scoped; error trackers don't know your queue.

Loopback is that missing loop, built as a hub:

one shared SQLite DB (~/.loopback/loopback.db). Agents registered once per machine; consuming repos add only a widget tag and a slug.

One instance, all projects. Every item is tagged with a project slug in

Gemini CLI are peers — same tools, same playbook, same audit trail.

One queue, all agents. MCP is the interface, so Claude Code, Codex, and

agent gets the failing POST with its 500 response body — a frontend pin carries the backend root cause. Pin an AI answer and the run metadata (runid, model, traceurl) rides along.

A pin is an anchor, not a scope. Pin a "broken" contact form and the

CAPTURE                          THE HUB                            AGENTS
 ┌───────────────────────────┐   ┌─────────────────────────────┐   ┌─────────────────────────┐
 │ widget pin on any app     │──►│  loopback-mcp-server        │◄──│ Claude Code             │
 │  · console + network ride │   │   one shared SQLite DB      │   │ Codex          (peers)  │
 │  · 500 bodies captured    │   │   ~/.loopback/loopback.db   │   │ Gemini CLI              │
 │  · AI run context         │   │                             │   └────────────┬────────────┘
 ├───────────────────────────┤   │  stdio (per-agent spawn)    │                │
 │ POST /ingest              │──►│  --http on 127.0.0.1:7077   │     list → claim → fix →
 │  · CI hooks, cron,        │   │   (required for widgets)    │     link change → fixed →
 │    Sentry/PostHog pollers │   │                             │     verify → resolve
 └───────────────────────────┘   └──────────────┬──────────────┘                │
                                                │                               │
              pins turn green on the page ◄─────┴───── status write-back ◄──────┘

Shortened. The full README is on GitHub.

Nothing above is checked by us. What we check is on the safety report.

Loopback: common questions

Is Loopback MCP server safe?: Yes, by our scan: it is graded A (88/100). Read the Loopback safety report
How do I install Loopback?: It runs on your machine. Copy the Claude Code, Cursor, VS Code or Claude Desktop config from the install section.
Does Loopback need an API key?: Not as far as the registry entry and our scan can tell: no credentials are declared or required.
Is Loopback maintained?: The last commit was 94 days ago (2026-08-02). The latest release is v0.9.4.
How does Loopback compare with other MCP servers?: safety score 88/100 (higher than 75% of 48,255 servers); tools 10 (the typical server has 7); tools that change things 30% (typical: 0%. Fewer write tools means less an agent can break). Full comparison.