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External Beta Program (M8)

The compatibility matrix proves Warden works for servers we chose and policies we wrote. This program collects the signal we cannot generate ourselves: can people who didn't design the policy schema use it?

Goal

5–10 MCP server maintainers/users run their own servers under Warden and report friction: where the schema was unclear, what had to be traced twice, which access pattern had no honest grant, and where they gave up.

How to join

  1. Install Warden (see Install) on Linux with bwrap (or macOS with sandbox-exec; Docker fallback works anywhere).
  2. Pick your server and trace it once: 
    warden trace -- <your-server-command>
warden init
  3. Review the generated policy.yaml, tighten it, and run sandboxed: 
    warden run --policy ./policy.yaml
  4. File a compatibility report (below) — one per server.

No NDA, no private channel: reports are public GitHub issues so the whole community sees the friction log.

Filing a compatibility report

Use the Compatibility report issue template, reproduced in full below so you can copy it here. Every report must include:

  • server name + upstream repo/commit,
  • host OS + backend (--backend value or auto resolution),
  • verdict: works / works-with-hacks / blocked,
  • the exact policy used (attach policy.yaml),
  • for every failure, your best-guess class:
  • Warden bug — it should work but doesn't,
  • schema gap — no honest grant expresses what the server needs,
  • inherent — the server needs something sandboxing forbids by design (arbitrary filesystem/URL access, daemon sockets),
  • the friction narrative: what was confusing, what you tried, where the docs/schema failed you.

Report template

File this as a GitHub issue on the repo (reports are public so the whole community sees the friction log). Source: .github/ISSUE_TEMPLATE/compat_report.md.

---
name: Compatibility report
about: Run your MCP server under Warden and report friction (M8 beta)
title: "[compat] <server-name>"
labels: compatibility
---

## Server

- Name / upstream repo + commit:
- Host OS + backend (`auto` resolution or explicit `--backend`):

## Verdict

<!-- works / works-with-hacks / blocked -->

## Policy

<!-- Attach the exact policy.yaml you ran with. Values are never stored in
     the policy — only env NAMES — so it is safe to paste. -->

```yaml
# paste policy.yaml here

Access the server needs

Failures (one per bullet)

-

Friction narrative

```

What maintainers do with reports

  • Reproduce against the report's policy; add passing servers to testdata/compat/ + matrix.yaml + docs/compatibility.md.
  • Classify confirmed failures into the three classes above and update the compatibility page.
  • Fix most-used-servers-first: Warden bugs before schema gaps, schema gaps before polish. Each fix ships with a regression test, like the M8 Normalize / ResolveExecutable fixes did.
  • Close the loop: comment the outcome on the reporter's issue.

Exit criteria

The beta has served its purpose when 5+ external reports are in, every reported failure is classified, and the highest-impact gaps found are fixed or explicitly scheduled. The matrix page then reflects reality, not just fixtures written alongside the backends.