Current scope of the V1 grammar and AST

The filename and grammar version remain V1 for compatibility: Iterion has evolved the original language additively rather than introducing a second file format. This is therefore a living scope statement, not the 2025 launch feature list. For exact productions, use iterion_v1.ebnf; for authoring guidance, use ../dsl.md.

Parsed declaration families

Family	Current surface
Inputs and reuse	top-level or workflow vars / attachments; top-level presets / secrets; workflow resources; compile-time group / use
Prompt and shape	prompt with bounded relative include, flat schema, cursor declarations
LLM execution	agent, judge, model/backend/provider selection, prompts, sessions, tools, permissions, skills, MCP, memory, cursors, compaction, reasoning/timeout limits
Deterministic execution	tool, Verified Action policy/recovery, compute, event emit, bounded event wait
Human control	human with none, human, llm, llm_or_human, or review interaction and review/merge fields
Routing	router modes fan_out_all, fan_out_each, condition, round_robin, and llm
Nested execution	subbot child runs, variable mapping, resource leases, and isolated workspace-safety assertion
Concurrent observation	supervisor declarations with watched nodes, cooldown, evaluation cap, model, and system prompt
Workflow	one workflow per file, entry, edges, defaults, permissions/capabilities/skills/MCP, budget, resources, interaction, worktree, compression, sandbox

Supported scalar/schema types are string, bool, int, float, json, and string[]; string declarations may carry an enum constraint.

Edges, iteration, and convergence

Edges support data mapping with with, guarded routing with when or else, and one iteration clause:

• bounded named loops, including runtime-resolved caps;
• explicit unbounded loops with fuel and runtime liveness protection;
• ordered finite as foreach name(item in collection) iteration.

Every graph cycle must be declared. Static and data-driven fan-out converge on a supported node with await: wait_all or await: best_effort. fan_out_each adds over, as, and optional key / depends_on fields for parallel map or DAG scheduling.

Expressions and templates

Quoted when and compute fields share the bounded expression language: field/index access, arithmetic, comparisons, booleans, conditionals, map/filter/reduce forms, and total collection built-ins. Expressions do not admit arbitrary functions or recursion.

Runtime templates cover vars, input, prior outputs and histories, artifacts, attachments, secrets, loop/foreach state, and run metadata. Compile-time group expansion additionally consumes {{params.name}}. Environment references use ${...}. Tool commands distinguish shell-escaped {{input.x}} from explicit raw {{!input.x}} substitution.

Still outside V1

Concept	Boundary
General source modules/imports	import "lib/x.bot" at the head of a file merges fragments under lib/ into ONE program (every declaration kind; keyed blocks by key; a name declared twice is E010). It is not a module system: no selective import, no renaming, no path outside the bot's lib/. A subbot is the runtime composition.
Multiple workflows in one file	The parser can represent them, but IR compilation emits C007; one file selects exactly one workflow.
Nested schema declarations	Schemas remain flat; use json for nested or open shapes.
Runtime node creation or inheritance	Groups clone a statically declared cluster at compile time; they do not create dynamic graph nodes or provide extends.
Arbitrary expression-language effects	Expressions cannot perform I/O, recurse, or invoke user-defined functions. Use a tool or an LLM node for effectful work.
Computed variable declarations	Variables are declared statically and resolved from defaults/presets/recipes/launch inputs. Dynamic values flow through node outputs and edge mappings.
Arbitrary annotations	The DSL exposes defined metadata such as descriptions and artifact labels, not an open annotation bag.

Parsing only builds the AST. Cross-reference checks, group expansion, graph validation, capability checks, routing safety, diagnostics, and IR generation remain compiler responsibilities under ../../pkg/dsl/ir/.

Syntax profiles (ADR-098)

The grammar file keeps its name: one grammar describes both profiles, and the dsl: N header selects how a few forms are READ. Absent means profile 1, the reading above, frozen. Profile 2 changes four readings — standard escapes in "…" strings with no directive, paragraph breaks kept in prompt bodies, the strict-escape directive refused, project_root: retired — and nothing else: the - item list form, the chain of arrows, the inline prompt string, the bare word as a string value and the bare literals in a with map are accepted in every profile, because a text that was invalid becoming valid changes no valid text's meaning. iterion dsl migrate --to 2 moves a file; iterion validate says when a headerless file is one the two profiles read differently (C144).