Parent: TechDevGroup/devagentic#203 (canonical fusion contract).

Gap

hermes does not auto-load kind:vertical-spec, kind:grafted-context, or kind:worker-guardrails docs as session preamble on boot. Only plugins/devagentic-canvas/preamble.py exists, and it loads CANVAS state (hermes issues #55/#56) — not vertical manifests.

What is needed

On hermes session boot (or first turn), when HERMES_HOME=~/.hermes/profiles/<user_id>:

1. Query devagentic for docs tagged user_id=<user_id> and kind in {vertical-spec, grafted-context, worker-guardrails}.
2. Render them as a pre-LLM preamble appended to the user message (same fail-soft contract as plugins/devagentic-canvas/preamble.py).
3. Cap injected size so a large vertical does not crowd out the user message.

Acceptance

• Worker session launched via HERMES_HOME=~/.hermes/profiles/<name> hermes automatically ingests its vertical-spec + grafted-context + worker-guardrails docs on first turn.
• Unit test exercising the loader with a fixture user_id.
• README/docs added under plugins/devagentic-vertical-preamble/ (or sibling location) describing the loader.

Notes

• Mirrors plugins/devagentic-canvas/preamble.py architecture.
• Per test: add unit tests for trajectory_compressor NousResearch/hermes-agent#203 §1.2 worker sessions never read genesis/doc.jsonl directly — this loader is the canonical path.