Product + Technical Spec: Target User Usability Harness

Product + Technical Spec: Target User Usability Harness (v0)

Status: PRD draft (not implemented).

Objective

Build a repeatable harness that simulates a target-user usability panel to surface pain points before human testing:

• import realistic photo sets,
• provide project context and constraints,
• drive Mother + Abilities over multiple turns,
• capture explicit "open pondering" and friction observations each turn,
• take UI screenshot evidence at key junctures so simulated users can react to visible state,
• produce scored, reproducible run artifacts with clustered pain-point evidence.

This harness is not a replacement for live user interviews; it is a pre-screening signal generator for likely UX friction in common scenarios.

Screenshot Requirement (Required)

• Every turn is driven by a screenshot captured from the app state.
• The simulator chooses actions from the latest image + events, not from hidden internal state alone.
• Screenshot paths are immutable and versioned in run artifacts.
• Reflection records must include which screenshot drove the decision and what changed since last capture.

Usability Framing

The harness should answer:

• Where do users stall or issue repeated fallback instructions?
• Which abilities are difficult to discover or sequence correctly?
• Which steps cause avoidable retries, confusion, or explicit user uncertainty?
• What error or ambiguity patterns recur across personas and scenarios?
• Which interface actions are too slow or feel fragile for target workflows?

Feasibility Snapshot

Feasibility is high because the required primitives already exist:

• brood-rs chat --out ... --events ... supports multi-turn interaction.
• Abilities already exist as slash commands (/diagnose, /argue, /bridge, /swap_dna, /triforce, etc.).
• events.jsonl is append-only and machine-readable.
• Native CLI + events.jsonl contracts already support deterministic multi-step experiment runs and telemetry capture.
• desktop/src/canvas_app.js already has snapshot capture helpers that write image files under runDir for intent/inference flows.

The missing piece is orchestration for persona-driven user behavior and pain extraction, not core model capability.

v0 Scope

• Adapter: CLI-first (brood-rs chat PTY) for speed and determinism.
• Persona + scenario pack input (JSON) with explicit usability hypotheses and expected friction points.
• Agentic turn loop with explicit reflection logging.
• Pain-point capture and severity scoring as first-class output.
• Ability coverage tracking and stop conditions.
• Scorecard per scenario and aggregate usability report.
• Key-juncture screenshot capture and reaction coupling.

Proposed Pain Output Contract

Every scenario run should produce:

• A per-turn friction stream with structured tags.
• A scenario-level pain summary grouped by category.
• Actionable mitigations where confidence allows, as suggestions for backlog triage.

Non-Goals (v0)

• Pixel-perfect desktop UI automation (v0 supports coarse scripted UI gestures only).
• Perfect simulation of human behavior.
• Using reflection text as hidden reasoning. Reflection is explicit, user-visible artifact data.

Pain Taxonomy (v0)

• discoverability: user does not know which ability or flow to use next.
• intent_ambiguity: unclear how to translate goal into a command.
• setup_friction: import/context/setup actions are too cumbersome.
• error_recovery: recoveries from provider or ability failures are slow/confusing.
• control_confidence: user is uncertain whether output matches goal.
• speed_timing: waiting or latency creates stress.
• sequence_break: user cannot compose a correct multi-step sequence.
• output_quality_gap: produced results are off-spec and require multiple retries.
• handoff_confusion: user is unsure how to continue after an intermediate output.

Architecture

Components:

• Scenario pack loader: validates persona/scenario config.
• Session runner: executes one scenario against one persona.
• Chat adapter: sends utterances/commands to brood-rs chat, tails events.jsonl.
• Screenshot adapter: captures, versions, and records app screenshots for each turn.
• Policy layer: chooses next action from scenario goals + recent events + latest screenshot.
• Reflection writer: writes explicit turn reflections to reflections.jsonl with pain tags.
• Pain extractor: normalizes and validates friction observations and aggregates them by scenario.
• Evaluator: computes success and rubric scores from artifacts/events/reflections.

Suggested code placement:

• rust_engine/crates/brood-cli/src/main.rs (CLI-side orchestration hooks)
• docs/target_user_harness.schema.json (config contract)
• docs/target_user_harness_pain.schema.json (if formalized later for shared validator usage)

Run Artifacts

For each scenario run:

• session.json: resolved persona/scenario/policy.
• events.jsonl: raw engine events (from Brood run dir).
• transcript.jsonl: adapter-level IO (user_input, assistant_output, command).
• screenshots.jsonl: ordered screenshot events (phase, path, turn, pre_or_post).
• reflections.jsonl: explicit per-turn pondering.
• pain_points.jsonl: structured friction annotations with taxonomy tags + severity.
• scorecard.json: rubric + pass/fail result.
• summary.json: compact outcome for dashboarding.
• usability_report.md: concise, human-readable pain-point review and priority list.

Across the full harness invocation:

• ux_improvements.md: prioritized cross-scenario UX improvements with evidence counts and suggested success metrics.
• ten_x_competitive_edge.md: candidate feature bets and problem-solving angles that could create a 10x competitive advantage.

State Machine

States:

1. init
2. capture_snapshot
3. start_chat
4. import_inputs
5. plan_turn
6. act
7. observe
8. reflect
9. score_checkpoint
10. done
11. error

Transitions:

• init -> capture_snapshot for initial baseline screenshot.
• capture_snapshot -> start_chat when scenario initializes and screenshot is saved.
• start_chat -> import_inputs when PTY and events are live.
• import_inputs -> capture_snapshot before turn planning begins.
• capture_snapshot -> plan_turn after bootstrap imports are reflected in UI.
• plan_turn -> act when next action is chosen.
• act -> capture_snapshot immediately after dispatch.
• capture_snapshot -> observe after screenshot write.
• observe -> reflect after event delta window closes.
• reflect -> capture_snapshot before next action (except terminal states).
• capture_snapshot -> score_checkpoint when scenario is done or failed.
• score_checkpoint -> plan_turn while stop condition is unmet.
• score_checkpoint -> done on success, budget exhaustion, or max turns.
• Any state -> error on unrecoverable adapter/engine failure.

Screenshot policy:

• Capture pre_action and post_action in each turn where available.
• Capture mandatory junctions: boot, import completion, generation completion, failure branch, and completion.
• In CLI mode, default capture strategy is auto: source-dir image, then live macOS window capture, then synthetic fallback.

Stop conditions:

• Success criteria satisfied.
• max_turns reached.
• max_cost_usd reached.
• max_runtime_s reached.
• Consecutive failure threshold reached.

Action Model

Three action forms are supported:

• utterance: natural language sent to Mother.
• command: explicit slash command to an Ability.
• ui: coarse desktop interaction (for desktop_ui adapter), such as focus, click, drag, keystroke, and wait.
  • Includes Mother controls: mother_next_proposal, mother_confirm_suggestion, mother_reject_suggestion.

Supported command.name in v0:

• use
• diagnose
• describe
• canvas_context
• blend
• bridge
• swap_dna
• argue
• extract_rule
• odd_one_out
• triforce
• recast
• quality
• fast
• cheaper
• better

Interpretation:

• Use utterance when simulating ambiguous user intent.
• Use command when simulating power-user behavior and explicit Ability invocation.
• Use ui when you need visible interaction traces (e.g., clicking canvas controls, moving images) before screenshot capture.
• ui actions are treated as setup/interaction steps and do not consume max_turns; max_turns gates chat/command turns.

Open Pondering Contract

Each turn must write one reflection record:

• turn: integer
• action_taken: normalized action record
• observed_signals: key events/artifacts in that turn
• what_worked: short text
• what_failed: short text
• open_questions: array of unresolved user-style questions
• next_hypothesis: what the simulated user will try next
• confidence: float 0.0..1.0
• screenshot_path: screenshot used for reasoning.
• screenshot_phase: pre_action or post_action
• screenshot_delta: list of notable visual changes.
• pain_points: array of objects
  • category: one of the taxonomy values
  • severity: 0.0..1.0
  • symptom: short sentence describing user pain
  • evidence: event/event-id references or transcript snippets
  • likely_cause: optional diagnosis hypothesis
• mitigation_hint: suggested improvement to reduce this pain in one sentence

This keeps usability issues explicit, auditable, and easy to triage across scenarios.

Scoring (v0)

Per scenario score is weighted:

• goal_progress (35%)
• artifact_quality_proxy (20%)
• ability_usage_quality (12%)
• efficiency_cost_time (12%)
• resilience (8%)
• reflection_quality (5%)
• friction_profile (18%)

friction_profile is derived from:

• weighted pain-point severity per scenario,
• pain recurrence on unresolved questions,
• count of distinct taxonomy categories triggered.

Pass gate:

• goal_progress >= 0.7
• at least one required ability used
• no fatal adapter errors
• friction_profile >= 0.6 (higher is better; pain-adjusted score)

Benchmark Scenarios (v0)

1. image_feature_regression_triage

• Persona: product engineer shipping in-app image features.
• Inputs: source image + failing release output + target reference.
• Goal: isolate likely failure causes and produce one improved direction.
• Required abilities: diagnose, canvas_context, argue.
• Likely pain targets: error_recovery, intent_ambiguity, sequence_break.

2. creative_direction_iteration_lane

• Persona: creative technologist / design-infra operator.
• Inputs: primary subject + two style references.
• Goal: create two distinct directions, then select one production-safe path.
• Required abilities: swap_dna, bridge, argue.
• Likely pain targets: discoverability, control_confidence, output_quality_gap.

3. multi_provider_cost_reliability_sweep

• Persona: AI agency/studio ops lead.
• Inputs: client source + campaign reference + known baseline output.
• Goal: produce a client-ready output and a cheaper fallback path.
• Required abilities: cheaper, blend, argue.
• Likely pain targets: speed_timing, output_quality_gap, handoff_confusion.

4. agent_intake_discoverability_check (secondary but intentional)

• Persona: founder/devrel owner optimizing agent discoverability.
• Inputs: screenshots of llms.txt entrypoints, intake contract, visibility probe.
• Goal: validate what an external agent can infer and identify one doc improvement.
• Required abilities: describe, canvas_context, extract_rule.
• Likely pain targets: discoverability, intent_ambiguity, setup_friction.

Rollout Plan

Phase 1 (engine-level):

• Implement CLI adapter and deterministic loop.
• Add screenshot-aware transcript/transition model and dryrun policy.
• Run scenario pack using dryrun and one live provider profile.

Phase 2 (evaluation hardening):

• Add score calibration and failure taxonomy.
• Add aggregate report for multi-run comparisons and recurring pain clusters.
• Add screenshot integrity checks and screenshot-derived reaction evidence.

Phase 3 (desktop fidelity):

• Ship desktop adapter that captures live app screenshots at each transition state.
• Add deterministic desktop playback harness and comparison snapshots.

Risks and Mitigations

• Simulation drift from real users. Mitigation: calibrate scenario pack from real anonymized usage motifs.
• Agent over-optimizes rubric. Mitigation: separate actor policy from evaluator policy/model.
• Flaky provider/network responses. Mitigation: retries, bounded backoff, and deterministic seeds where possible.

Acceptance Criteria

• Run all benchmark scenarios from one JSON pack.
• Produce complete artifact bundle per scenario.
• Emit structured pain record each turn, including screenshot evidence fields.
• Generate deterministic summary for repeated seeded runs.
• Aggregate recurring pain themes into a usability summary with severity ranking.
• Capture all required screenshots with stable filenames and references.
• Complete without manual intervention in desktop adapter mode.