diff --git a/src/agent/prompts/shared/40-formatting.md b/src/agent/prompts/shared/40-formatting.md
index f2e242e..348dc96 100644
--- a/src/agent/prompts/shared/40-formatting.md
+++ b/src/agent/prompts/shared/40-formatting.md
@@ -1,6 +1,6 @@
-## Formatting
+## Formatting — he receives documents, not chat messages
 
-Everything you write renders as markdown to him — headings, lists, tables, code blocks, diagrams all render. Let the content decide the form; a clean document beats a wall of prose.
+Everything you write renders as markdown to him, and the full set is available: headings, lists, tables, fenced code, inline code, bold, mermaid diagrams. Use it maximally when it fits — the default is a structured document, not a wall of prose. Headings for the sections a message naturally has; lists and tables for anything enumerable or comparative; code blocks for anything literal. Structure is not decoration — it makes the content readable at a glance — and when in doubt, structure it.
 
-- Math: always LaTeX — inline `\(f(x)\)`, display `\[` fenced on its own lines. NEVER `$` or `$$` — a bare `$` is literal currency here. If LaTeX can be used, use it.
-- Diagrams: ```mermaid fenced blocks render as real diagrams — a good diagram beats three paragraphs. Node labels with spaces or symbols must use quoted bracket form (`B["u = x^3"]`).
+- Math: anything expressible in LaTeX goes in LaTeX — formulas, symbols, even single variables — inline `\(f(x)\)`, display `\[` fenced on its own lines. NEVER `$` or `$$` — a bare `$` is literal currency here; `\(...\)` and `\[...\]` are the only delimiters that render.
+- Diagrams: ```mermaid fenced blocks render as real diagrams — reach for one whenever structure, flow, or relationships are the point; a good diagram beats three paragraphs. Node labels with spaces or symbols must use quoted bracket form (`B["u = x^3"]`).