AILang/skills/brainstorm/SKILL.md

name, description

name	description
brainstorm	Use when a new milestone is starting — gathers requirements, explores 2-3 approaches with trade-offs, presents a sectioned design with user approval, writes the spec to docs/specs/. Hard-gate before any plan or code work; applies even when the user says they have a clear vision.

brainstorm — milestone spec generator

Violating the letter of these rules is violating the spirit.

Overview

The spec is where the orchestrator does the design work. It is the artefact that future iterations, the architect agent, and any future LLM read to understand WHAT the milestone delivers and WHY. Skipping the spec means shipping the user's intuition unfiltered, which is exactly the reactive-deference failure mode AILang's orchestrator discipline exists to prevent.

It produces specs at docs/specs/<milestone>.md.

When to Use / Skipping

Triggers:

• A new milestone is starting (e.g. user proposes a new feature area, a new subsystem, or a major refactor of an existing one).
• A milestone-scope spec is missing for an existing line of work and one is needed retroactively.

Skipping is permitted only for:

• A bug-fix iteration (use debug directly).
• A tidy iteration (use audit directly).
• A trivial mechanical edit (≤1 file, ≤30 LOC, no design judgement).

Skipping is not permitted for:

• A user request framed as "I have a clear vision, just plan it".
• A milestone described as "small, only two iterations".
• A milestone where you are confident you know what to build.

The first two cases above are the most common pressure to skip; both are explicitly resisted by this skill (see Common Rationalisations).

The Hard-Gate

NO IMPLEMENTATION, SCAFFOLDING, OR DOWNSTREAM SKILL INVOCATION
UNTIL A SPEC HAS BEEN PRESENTED AND THE USER HAS APPROVED IT.

The hard-gate applies regardless of perceived simplicity. The spec can be short for a small milestone (a few sections), but it MUST exist and be approved before any plan or code work begins.

The Process

Step 1 — Explore project context

Before asking any clarifying questions:

• Read the latest entries linked from docs/journals/INDEX.md (most recent milestones, current state).
• Skim docs/DESIGN.md for the invariants the new milestone might touch.
• git log --oneline -20 to see what just shipped.
• Identify scope: is this one milestone, or does it need to be decomposed into sub-milestones first? If multi-subsystem, decompose.

Step 2 — Ask clarifying questions, one at a time

Multiple-choice when possible (easier to answer). One question per message — no batching. Focus on:

• Purpose: what problem does this solve?
• Constraints: what semantic / performance / compatibility invariants must hold?
• Success criteria: how do we know it shipped?
• Scope: what is OUT of scope?

Step 3 — Propose 2-3 approaches with trade-offs

Lead with your recommended option and explain why. Each approach gets:

• core idea (1-2 sentences)
• the AILang program first, code not prose. The primary artifact is the .ail (Form-A) program that should work under this approach — the code the language is for. Show it. The implementation shape (changed struct/signature/match-arm, before → after) is secondary supporting detail — "also useful, not the point" — include it but never let it stand in for the .ail. "The approach extends the struct with a field" is not an approach; the .ail it makes work (or correctly reject) is.
• substantive trade-offs (semantic fit, schema impact, performance, composability)
• effort observation (NOT effort as rationale — see CLAUDE.md "Design rationale ≠ implementation effort")

Wait for user choice before proceeding.

Step 4 — Apply the feature-acceptance criterion

A feature ships only if all three hold:

• An LLM author (= future me) naturally produces code that uses it, AND
• The feature measurably improves correctness or removes redundancy, AND
• It reintroduces no bug class the core constraint exists to eliminate. Criterion 1 does not discriminate — an LLM reaches for every construct native to its imperative training distribution, so "the LLM reaches for it" is satisfied by exactly the constructs AILang most deliberately refuses. A documentation note is not a reshape: the gate is whether the wrong code fails to typecheck, not whether a guideline advises against it.

Aesthetic appeal does not count. Human ergonomics do not count. If the answer to any of the three is "I'm not sure", the feature is probably not ready. The full criterion (with the canonical worked example — see the criterion text) lives in docs/DESIGN.md ("Feature-acceptance criterion"); this skill is the gate that applies it during spec writing.

Clause 1 is unjudgeable without the worked author code. For any milestone with authoring surface, the spec MUST contain the actual Form-A (.ail) example an LLM author would write — and that example is the clause-1 evidence. A prose assertion ("an LLM naturally reaches for X") with no shown code is exactly the unfalsifiable hand-wave the criterion exists to prevent: write the code the LLM would write, then judge whether it is in fact what the criterion demands. For an infrastructure milestone with no author surface there is still concrete AILang code: show the actual .ail the milestone delivers — frequently a test fixture whose correct behaviour is rejection (wrong code must fail to typecheck — the clause-3 discriminator) — plus a minimal, honest slice of the north-star program the infrastructure exists to serve (provisional surface explicitly flagged, never a vague non-normative hand-wave). "This milestone has no surface so there's no AILang code to show" is the rationalisation to refuse: an infra milestone that cannot be tied to concrete AILang code is speculative infra. (AILang's own thesis is structured concrete form over prose description; a spec that describes code in prose is incoherent with the language it specifies.)

Step 5 — Present design in sections

Scale each section to its complexity (a few sentences if straightforward, up to 200-300 words if nuanced). Cover:

• Architecture
• Components
• Data flow
• Error handling
• Testing strategy

The AILang program is the headline; the implementation shape is supporting. The ## Concrete code shapes section leads with the .ail (Form-A) program — the worked author example for a surface milestone (= the Step-4 clause-1 evidence), or the delivered fixture-and-north-star for an infra milestone (per Step 4). The before → after implementation shape (struct / signature / match-arm) follows as a clearly secondary subsection — "also useful, not the point" — never first, never a substitute for the .ail. Prose may explain code, never replace it. Exact bytes/line-numbers remain the planner's job (planner Iron Law) — the spec owns the shape, shown, with the AILang program foremost.

Ask after each section whether it looks right. Be ready to revisit earlier sections if a later one surfaces a contradiction.

Step 6 — Write the spec

Path: docs/specs/YYYY-MM-DD-<milestone>.md.

Structure:

# <Title> — Design Spec

**Date:** YYYY-MM-DD
**Status:** Draft — awaiting user spec review
**Authors:** Brummel (orchestrator) + Claude

## Goal
## Architecture
## Concrete code shapes
## Components
## Data flow
## Error handling
## Testing strategy
## Acceptance criteria

## Concrete code shapes is mandatory and leads with the AILang program: the worked .ail author example for an authoring-surface milestone (= the Step-4 clause-1 evidence), or — for a no-surface infra milestone — the .ail the milestone delivers (often a must-fail fixture) plus a minimal honest north-star slice (Step 4). The before → after implementation shape for each load-bearing change follows as an explicitly secondary subsection, never first.

Step 7 — Self-review

Inline checklist (not a subagent dispatch):

1. Placeholder scan: any "TBD", "TODO", incomplete sections, vague requirements? Fix.
2. Internal consistency: sections must not contradict. Architecture must match component descriptions.
3. Scope check: focused enough for one plan, or does it need sub-milestone decomposition?
4. Ambiguity check: could any requirement be interpreted two ways? If so, pick one and make it explicit.
5. Concrete-code check: does ## Concrete code shapes exist and carry before → after code for every load-bearing change (plus the worked .ail example for an authoring-surface milestone)? A load-bearing change described only in prose is a self-review failure to fix, exactly like a placeholder.

Fix issues inline. No need to re-review — fix and commit.

Step 7.5 — Grounding-Check Agent (hard-gate)

Dispatch the read-only ailang-grounding-check agent. The agent reads the just-written spec with fresh context, extracts its load-bearing assumptions about current compiler / checker / codegen / schema behaviour, and for each one searches the workspace for a currently-green test that ratifies it.

Dispatch carrier:

Field	Content
spec_path	path to the spec just written in Step 6
iteration_scope	which sections cover the imminent first iteration (verbatim from the brainstorm session)

The agent returns a PASS / BLOCK / INFRA_ERROR report. Boss interpretation:

Agent status	Boss action
PASS	Proceed to Step 8. The report goes into the brainstorm chat for the record.
BLOCK	Present the report to the user. User either: (a) accepts discard → execute the failure-mode procedure below; or (b) overrides in free chat ("Test <path>::<name> ratifies that") → log the override note in the brainstorm chat and proceed to Step 8.
INFRA_ERROR	Abort the brainstorm. The spec stays as-is on disk; debug the workspace out-of-band and re-dispatch the agent.

Failure-mode procedure (no-override BLOCK):

1. Delete the just-written spec file from the working tree (rm docs/specs/<spec_filename>.md — a Bash-level delete on the working tree, NOT git rm; the file was never committed).

2. Append a roadmap entry to docs/roadmap.md pointing forward to a future re-brainstorm, under the appropriate priority bucket:

   - [ ] **[<kind>]** <idea title> — <one-line description>
     - context: <why this is deferred>
     - depends on: <name of the unratified mechanism>
   

3. Tell the user the spec was retired and which roadmap entry was added. The user / Boss commits the roadmap edit (suggested commit subject: spec: retire <spec topic> — depends on <unratified mechanism>).

After the failure-mode procedure runs, the brainstorm session ENDS. There is no Step 8, no Step 9. The idea is parked until the dependency ships, at which point a fresh brainstorm session re-derives the spec from scratch.

Re-dispatch on any post-PASS edit. The grounding-check PASS report is bound to the exact bytes of the spec at dispatch time. Any subsequent edit to the spec file — Boss-side polish, a user-requested change in free chat, a wording tighten, anything — invalidates the PASS report and requires a fresh dispatch of ailang-grounding-check before Step 8 commit. Step 7.5 is the last step that touches the spec file; nothing slips between it and the commit.

Step 8 — User-review gate

The spec sits in the working tree as an unstaged file. Tell the user:

Spec written to <path> (uncommitted). Please review it and let me know if you want changes before we start the implementation plan. The Boss will commit it once you approve.

Wait for the user's response. If they request changes, edit the file in place (still uncommitted), re-run Step 7 AND re-dispatch Step 7.5 (the previous PASS report no longer covers the edited bytes), then return here. Only proceed to the next step after approval AND a fresh Step 7.5 PASS.

The Boss commits the approved spec after the user signs off (suggested commit subject: spec: <milestone> <topic>). The brainstorm skill does not perform the commit itself.

Step 9 — Hand off to planner

The terminal state of brainstorm is invoking planner. NO other skill is invoked from brainstorm. NO direct jump to implement.

Hand off carries:

• path to docs/specs/<milestone>.md
• iteration scope ("the first iteration covers section X+Y of the spec")

Handoff Contract

Direction	Carrier
user → brainstorm	new milestone request
brainstorm → ailang-grounding-check (Step 7.5)	spec_path + iteration_scope
brainstorm → planner (Step 9, on PASS or overridden BLOCK)	path to spec + iteration scope
brainstorm → roadmap (Step 7.5, on no-override BLOCK)	depends on: entry added to docs/roadmap.md in the working tree, spec file deleted from the working tree; Boss commits the roadmap edit

Common Rationalisations

Excuse	Reality
"User says 'clear vision, just plan it' — skip the spec"	"Clear vision" is a starting point, not a spec. The user's intuition hasn't priced in semantic commitments (RC, uniqueness, codegen, schema). Write the spec; frame it as "load-bearing decisions this idea forces on us".
"Milestone is small, two iterations, no spec needed"	Iteration count isn't the metric — feature surface is. A two-iter feature touching DESIGN.md invariants needs a spec; a CLI flag does not. Assess what the feature changes in invariants.
"Three approaches in, none feel right, ship the least bad"	Three unsatisfying approaches usually means the problem is mis-framed. Stop, write a JOURNAL entry capturing the three approaches and what fails about each, sleep on it. End-of-day pressure is the worst signal to resolve a design fork.
"User is busy, present my own design without Q&A"	Reactive deference disguised as decisiveness. The Q&A surfaces constraints the user hasn't articulated; skipping it means shipping the user's defaults, not their intent.
"Spec exists from previous milestone, append to it"	New milestone = new spec file. The architect agent reads spec files per milestone; mixing scopes makes drift review unreadable.
"Approaches A, B, C are all bad — proceed with A"	This is exactly the moment to surface "the problem is mis-framed" rather than ratify a known-bad shape into DESIGN.md. JOURNAL the impasse, escalate to user.
"Just polishing a wording after PASS, no need to re-dispatch"	The grounding-check report attests to specific bytes. A polish edit changes the bytes; the previous attestation no longer covers them. Re-dispatch is cheap; the alternative is a commit with an attestation that doesn't match the file.
"The shape is clear from the prose, I don't need to paste the code"	If it's clear, pasting it is free; if pasting it is hard, it wasn't clear. Clause 1 is unjudgeable without the worked .ail; "an LLM reaches for it" with no shown code is the exact hand-wave the criterion exists to kill. Prose about code is incoherent with a language whose thesis is structured-form-over-prose.

Red Flags — STOP

• "Skip the spec" thoughts (any flavour)
• "One paragraph is enough"
• "User said it's clear, who am I to push back"
• "The 2-3 approaches all suck, just pick one"
• Skipping Step 7 self-review because "I wrote it carefully"
• A load-bearing change described in prose with no before → after code block; an authoring-surface milestone with no worked .ail example
• Editing the spec file after a Step 7.5 PASS without re-dispatching
• Jumping straight from spec to implement (must go via planner)
• Inventing a design rationale that's actually about effort, not semantics

Cross-references

• Project source: docs/DESIGN.md "Feature-acceptance criterion" — gate this skill applies during spec writing.
• Output target: skills/planner/SKILL.md — only valid next skill.
• Private agent: skills/brainstorm/agents/ailang-grounding-check.md — dispatched in Step 7.5 as a hard-gate. The agent reads the spec with fresh context and reports PASS / BLOCK / INFRA_ERROR. See docs/specs/2026-05-11-brainstorm-grounding-check.md for the design rationale.
• Ad-hoc dispatch. The Boss MAY also ad-hoc dispatch skills/planner/agents/ailang-plan-recon.md during Step 1 when the milestone enters code territory the Boss has not recently read; this is opt-in and not part of the standard process. Rationale: brainstorm's recon phase is interwoven with the user Q&A — see docs/specs/2026-05-11-plan-recon-subagent.md for the full reasoning.