We define what happens when markup keywords are encountered by the breadth-first evaluator. See Extract Site to Dot for examples, Graphviz Eval Emerges for implementation experience, Dynamic Diagrams in Use for next steps, and More About Algorithmic Markup for this page translated into advice.
# Context
Context is established by keywords, used in place and passed as a copy to nested markup.
Keywords that establish a page title, a name in context, do not immediately fetch that page.
Keywords that successfully fetch pages establish that content as the page in context for nested markup.
Keywords can subset the page in context and pass that to nested markup.
Lines without keywords will pass through as is. dot 
# Keywords
DOT digraph
DOT strict digraph
DOT graph
DOT strict graph
Engage the algorithmic translation of linked wiki pages using the following additional keywords. We support the four dot variations shown.
DOT FROM slug
Transclude here the Graphviz markup from an item on the page identified by slug. This markup may be any markup except another DOT FROM. Use this to apply a diagramming strategy in many places while revising that strategy in only one.
HERE
HERE NODE
HERE NODE label
The name in context is established as a page to be examined. A fetch is initiated. The page becomes the page in context. Optionally render as node. Optionally render the labeled markup node with a dotted edge to node here.
LINK
LINK HERE -> NODE
LINK HERE -- NODE
LINK NODE -> HERE
LINK NODE -- HERE
The page in context or WHERE-portions thereof are examined for internal links. These become the name in context for nested markup. Optionally render an edge from/to the page in context to/from each new name in context.
WHERE /reg-ex/
WHERE graph
The page in context is examined for items matching a condition which become the subset page in context for nested markup.
ELSE
When the preceding HERE fails to retrieve and establish a page in context then nested markup is evaluated with the previous context in place.
FAKE NODE -> HERE
FAKE NODE -- HERE
FAKE HERE -> NODE
FAKE HERE -- NODE
Render an edge from/to the name in context (failed page in context) to/from a fabricated node name based on adding a prefix (pre or post) and an occurrence name (one, two or three) to the name in context.
LINEUP
The site and slug of leftward lineup pages become the name in context for nested markup.