synthesis-message-guard SKILL.md skillA
synthesis-message-guard from synthesisengineering/synthesis-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add synthesisengineering/synthesis-skills/synthesis-message-guard@v2.5.1Pins v2.5.1 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- synthesisengineering/synthesis-skills
- Path
skills/synthesis-message-guard/SKILL.md- Versions recorded
- 18
- Latest version
- v2.5.1, committed Oct 27, 2026
- First version recorded
- Sep 1, 2026
- Size
- 7,183 bytes
- Repository stars
- 23
- License
- Apache-2.0
Send guard for agent-drafted messages: no send or draft goes out until the principal approves that exact call, and the text passes the register scan and format rules (HTML email, whole paragraphs, linked signatures, literal Message-IDs). Use when composing, configuring, or when a send is blocked.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Message Guard Prose rules do not survive contact with a model under load. This skill is the enforcement layer for correspondence the way commit hooks are the enforcement layer for repositories: the rules live in code, run outside the model, and fail closed. The v5 PreToolUse hook runs `guards.check_send` on every Slack, Gmail, email, chat and draft tool call: the text must pass the principal's register scan and the format rules, and then the principal must approve that exact call. ## Binding rules 1. **The principal approves the exact call.** A blocked send files a request with a six-character code; only the principal typing `approve <code>` in their own prompt grants it (the harness's transcript must show it), for one identical call within 15 minutes. Never grant one yourself. Any change after approval (a recipient, cc, bcc, subject, thread, any body part, an attachment) needs a new approval. …
Read the whole file at its exact version.
How to install
mdr add synthesisengineering/synthesis-skills/synthesis-message-guard@sha256:7b868668466429e9The line at the top of this page pins the label v2.5.1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_yqtf2xd2ptfuz6k5)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 18 versions of this file, between Sep 1, 2026 and Oct 27, 2026, about one every 3 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v2.5.1 latest | 2026-10-27 | 0fa66e3 | 7,183 B | A | view · diff |
| v2.5.0 | 2026-10-27 | 00513b6 | 7,183 B | A | view · diff |
| v2.4.1 | 2026-10-26 | c7b985b | 7,128 B | A | view · diff |
| v2.4.0 | 2026-10-22 | 89be12d | 7,128 B | A | view · diff |
| v2.3.1 | 2026-10-22 | 52c5c08 | 7,010 B | A | view · diff |
| v2.3.0 | 2026-10-22 | 0d56a29 | 7,010 B | A | view · diff |
| v2.2.1 | 2026-10-20 | 2a5dd6b | 6,399 B | A | view · diff |
| v2.2.0 | 2026-10-14 | cdf5f9d | 6,399 B | A | view · diff |
| v2.1.0 | 2026-10-13 | 8b14292 | 6,333 B | A | view · diff |
| v2.0.0 | 2026-10-06 | 95334b3 | 5,133 B | A | view · diff |
| v2.0.0 | 2026-10-06 | 8191e9d | 4,936 B | A | view · diff |
| v1.8.0 | 2026-09-28 | 6725b62 | 26,398 B | A | view · diff |
| v1.7.0 | 2026-09-27 | 95144f1 | 26,176 B | A | view · diff |
| v1.6.0 | 2026-09-02 | 61d6d1a | 12,649 B | A | view · diff |
| v1.5.0 | 2026-09-02 | 423aad4 | 12,257 B | A | view · diff |
| v1.5.0 | 2026-09-02 | 229c2d5 | 11,587 B | A | view · diff |
| v1.3.0 | 2026-09-01 | 5643132 | 10,352 B | A | view · diff |
| v1.2.0 | 2026-09-01 | ec476bb | 9,811 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (7183 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
synthesisengineering/synthesis-skills · 23 stars · license Apache-2.0 · pushed 2026-11-05 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_yqtf2xd2ptfuz6k5 GET https://markdownregistry.com/api/v1/resolve?ref=synthesisengineering/synthesis-skills/synthesis-message-guard GET https://markdownregistry.com/api/v1/blob/7b868668466429e92d67baeb3350a003cbf97e0f3571e5a6bf00e593e427a0dc
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.