## Summary
The DNS and HTTP authentication guides currently run `openssl genpkey
-algorithm Ed25519 -out key.pem` without caveat. macOS ships LibreSSL as
the system `openssl` binary, and LibreSSL doesn't implement Ed25519 in
`genpkey` — so the very first command in the Ed25519 codepath errors out
with:
```
Algorithm Ed25519 not found
```
A first-time integrator on macOS hits this immediately, with no path to
a fix from the docs alone. Cost me ~5 minutes earlier today before I
figured out I needed `brew install openssl@3` and an explicit binary
path.
This PR adds a `<Note>` callout to the **DNS Authentication** section
right above the Ed25519 codepath, and a shorter cross-reference Note in
the **HTTP Authentication** section since the same `openssl genpkey
-algorithm Ed25519` commands appear there. The ECDSA P-384 codepath
works on LibreSSL, so it's untouched.
## Test plan
- [x] Verified locally that `/opt/homebrew/opt/openssl@3/bin/openssl
genpkey -algorithm Ed25519 -out key.pem` works on macOS Darwin 25.4.0
- [x] Verified the system `/usr/bin/openssl genpkey -algorithm Ed25519
-out key.pem` fails with `Algorithm Ed25519 not found` on the same
machine (LibreSSL 3.3.6)
- [x] Verified the published `ai.ravenmcp/raven-mcp` flow end-to-end
with the OpenSSL 3 binary
- [ ] Markdown rendering of the `<Note>` callouts — relying on the
existing `<Note>` pattern in this file (line 6) to validate the syntax
Co-authored-by: Radoslav Dimitrov <radoslav@stacklok.com>
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