Meridian:spec Phase

/meridian:spec-phase — Spec Phase Type

Clarifies WHAT a phase delivers through a Socratic interview loop with quantitative ambiguity scoring. Produces SPEC.md in the phase artifact directory with falsifiable requirements locked before implementation decisions begin.

Position in workflow: spec-phase → discuss-phase → plan-phase → execute-phase

Arguments

• (no args) — spec the current pending/planned phase
• --phase <id> — spec a specific phase by ID
• --auto — skip interview if ambiguity already ≤ 0.20; otherwise Claude selects best answers
• --skip-spec — bypass gate warning in /meridian:plan (emergency only)

Keywords

spec, specification, requirements, clarify, ambiguity, scope, boundaries, falsifiable, what, deliverable, acceptance criteria, pre-plan, contract

Ambiguity Model

ambiguity = 1.0 − (0.35×goal + 0.25×boundary + 0.20×constraint + 0.20×acceptance)

Gate: ambiguity ≤ 0.20 AND all dimensions ≥ minimums → write SPEC.md.

Procedure

Step 1: Find Target Phase

PYTHONPATH=$MERIDIAN_HOME uv run --project $MERIDIAN_HOME -- python -c "
import json
from scripts.db import connect, get_db_path
from scripts.spec_phase import get_spec_context
conn = connect(get_db_path('.'))
ctx = get_spec_context(conn, phase_id=<phase_id_or_None>)
print(json.dumps(ctx, indent=2, default=str))
conn.close()
"

Pass the --phase <id> value as phase_id, or None if not specified.

If result contains "error", display it and stop — tell the user to run /meridian:plan first.

Store: phase_id, phase_name, description, acceptance_criteria, tech_stack, phase_dir, slug, initial_scores, initial_ambiguity.

Step 2: Check for Existing SPEC.md

PYTHONPATH=$MERIDIAN_HOME uv run --project $MERIDIAN_HOME -- python -c "
from pathlib import Path
from scripts.spec_phase import check_spec_artifact
result = check_spec_artifact(Path('<phase_dir>'))
print('exists' if result else 'missing')
"

If exists:

• --auto: proceed with "Update it" automatically. Log: [auto] SPEC.md exists — updating.

• Otherwise: use AskUserQuestion:

  • header: "Spec Phase"
  • question: "SPEC.md already exists for Phase : . What do you want to do?"
  • options: ["Update it", "View it", "Skip (use existing)"]

  If "View": display the SPEC.md content, then offer ["Update it", "Skip"]. If "Skip": print Existing SPEC.md unchanged. Run /meridian:discuss --phase <id> to continue. and exit. If "Update": continue.

Step 3: Scout Codebase

Before any questioning, understand current state:

1. Read .planning/PROJECT.md, .planning/REQUIREMENTS.md, .planning/ROADMAP.md (or check if they exist at those paths)
2. Read the phase's description and acceptance_criteria from context
3. Grep the codebase for code/files relevant to this phase goal — look for:
   • Existing implementations of similar functionality
   • Integration points where new code will connect
   • Test coverage gaps relevant to the phase
   • Prior phase artifacts (SUMMARY.md, VERIFICATION.md, RESEARCH.md) in phase_dir

Synthesize: what exists today vs what the phase must deliver. Hold this internally — use it to ask precise, grounded questions.

Step 4: Initial Ambiguity Assessment

Use the initial_scores from Step 1 context. Display:

## Initial Ambiguity Assessment — Phase <N>: <phase_name>

<format_scores output>

If --auto AND initial_ambiguity ≤ 0.20 AND all minimums met: Skip interview — derive SPEC.md from roadmap + requirements context. Log: [auto] Phase requirements are already sufficiently clear — generating SPEC.md. Jump to Step 7.

Step 5: Socratic Interview Loop

Run up to 6 rounds. Each round: 2–3 focused questions. One AskUserQuestion call per round.

Track current scores (start from initial_scores). Track round_number (starts at 1).

Interview perspectives by round:

• Round 1: Researcher — ground in current reality

  • "What exists in the codebase today related to this phase?"
  • "What's the delta between today and the target state?"
  • "What triggers this work — what's broken or missing?"

• Round 2: Researcher + Simplifier — surface minimum viable scope

  • "What's the simplest version that solves the core problem?"
  • "If you had to cut 50%, what's the irreducible core?"

• Round 3: Boundary Keeper — lock the perimeter

  • "What explicitly will NOT be done in this phase?"
  • "What adjacent problems are tempting to solve but shouldn't be?"
  • "What does 'done' look like — what's the final deliverable?"

• Round 4: Failure Analyst — find invalidating edge cases

  • "What's the worst thing that could go wrong if we get requirements wrong?"
  • "What does a broken version of this look like?"
  • "What would cause a verifier to reject the output?"

• Rounds 5–6: Seed Closer — lock remaining undecided territory

  • Focus questions on the lowest-scoring dimensions
  • "We have at — what would make it completely clear?"

For each round:

1. Ask questions via AskUserQuestion:

   • header: "Spec Round — "
   • question: "<2-3 focused questions formatted clearly>"
   • (free-text response — use the freeText: true option or plain question if AskUserQuestion doesn't support free text; display questions as text and await user response)

2. After user answers, update dimension scores based on what was clarified:

   • Each clear answer to a boundary question → increase boundary_clarity
   • Each clear constraint → increase constraint_clarity
   • Each testable AC → increase acceptance_criteria
   • Clearer goal statement → increase goal_clarity

3. Display updated scores:

After round <N>:
<format_scores output>

4. Gate check:

PYTHONPATH=$MERIDIAN_HOME uv run --project $MERIDIAN_HOME -- python -c "
import json
from scripts.spec_phase import gate_passed, compute_ambiguity
scores = <current_scores_as_dict>
passed, failing = gate_passed(scores)
ambiguity = compute_ambiguity(scores)
print(json.dumps({'passed': passed, 'failing': failing, 'ambiguity': ambiguity}))
"

If gate passes:

• --auto: jump to Step 7.

• Otherwise: AskUserQuestion:

  • header: "Spec Gate Passed"
  • question: "Ambiguity is — requirements are clear enough to write SPEC.md. Proceed?"
  • options: ["Yes — write SPEC.md", "One more round", "Done talking — write it"]

  If "Yes" or "Done talking": jump to Step 7. If "One more round": continue.

If max rounds (6) reached and gate NOT passed:

• --auto: proceed to Step 7, flagging unresolved dimensions in Ambiguity Report. Log: [auto] Max rounds reached. Writing SPEC.md with <N> dimensions below minimum.

• Otherwise: AskUserQuestion:

  • header: "Max Rounds Reached"
  • question: "After 6 rounds, ambiguity is . Dimensions still below minimum: . What would you like to do?"
  • options: ["Write SPEC.md anyway — flag gaps", "Keep talking", "Abandon"]

  If "Write": proceed to Step 7. If "Keep talking": continue (no round limit). If "Abandon": print Spec abandoned. No SPEC.md written. and exit.

Step 6: Derive SPEC.md Content

Before writing, synthesize from everything gathered:

Goal statement (1-2 sentences, specific and measurable):

• Based on phase description + interview clarifications

Requirements (list of 3-8 items):

• Each must be: one specific testable statement
• Format: "Current state: X. Target state: Y. Verified by: Z."
• No vague requirements ("should be fast", "improve UX")
• Good: "CLI command exits code 1 + stderr on invalid input"
• Good: "API responds < 200ms p95 under 100 concurrent requests"

In scope (explicit list of what this phase produces):

• Concrete deliverables, not wishes

Out of scope (explicit list of what it does NOT do, with brief reasoning):

• At least 2-3 items per phase to prevent scope creep

Constraints (performance, compatibility, data, tooling):

• Empty list is acceptable if none apply

Acceptance criteria (pass/fail checkboxes):

• Must be objectively verifiable
• No "looks good", "feels right", "seems reasonable"

Step 7: Write SPEC.md

PYTHONPATH=$MERIDIAN_HOME uv run --project $MERIDIAN_HOME -- python -c "
import json
from pathlib import Path
from scripts.db import connect, get_db_path
from scripts.spec_phase import write_spec_md, mark_spec_complete
conn = connect(get_db_path('.'))
path = write_spec_md(
    phase_dir=Path('<phase_dir>'),
    phase_name='<phase_name>',
    phase_id=<phase_id>,
    goal='''<goal_statement>''',
    requirements=<requirements_as_list>,
    in_scope=<in_scope_as_list>,
    out_of_scope=<out_of_scope_as_list>,
    acceptance_criteria=<ac_as_list>,
    constraints=<constraints_as_list>,
    final_scores=<scores_as_dict>,
    unresolved_dimensions=<unresolved_list_or_empty>,
)
mark_spec_complete(conn, <phase_id>, <ambiguity_score>, <requirement_count>)
conn.close()
print(str(path))
"

Step 8: Display Summary

## Spec Complete: <Phase Name>

Artifact: <phase_dir>/SPEC.md
Requirements locked: <N>
Ambiguity: <final_score> (gate: ≤ 0.20) [PASS / PASS with gaps]

Next: /meridian:discuss --phase <phase_id>
  discuss-phase will detect SPEC.md and focus on implementation decisions only.

Gate Behavior

/meridian:plan and /meridian:execute can check for SPEC.md using spec_gate():

PYTHONPATH=$MERIDIAN_HOME uv run --project $MERIDIAN_HOME -- python -c "
import json
from pathlib import Path
from scripts.spec_phase import spec_gate
result = spec_gate(Path('<phase_dir>'))
print(json.dumps(result, indent=2))
"

• passed: true → proceed normally
• passed: false → print the warning string; user can bypass with --skip-spec

This is a soft gate — it warns but does not block execution.

Critical Rules

• Scout codebase BEFORE the first question — grounded questions only
• Max 2–3 questions per round — never frontload all questions at once
• SPEC.md is NEVER written if user selects "Abandon"
• Do NOT ask about HOW to implement — that is discuss-phase territory
• Every requirement must have current state, target state, and acceptance criterion
• Boundaries section is MANDATORY — cannot be empty
• Acceptance criteria must be pass/fail — no subjective criteria