nanodevice_e2e_design

nanodevice_e2e_design -- End-to-End Device Design

A device-agnostic methodology for designing nanodevices on material regions in KLayout. The agent follows 7 reasoning steps, deriving device-specific physics rules from context and user input. No device type is hardcoded.

This is a pure-text orchestrator skill. No scripts directory. The agent uses MCP tools and sub-skills at each step.

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Pipeline Overview

#	Step	What the agent does	Skip when
1	QUERY	Check if required info is missing; ask only if needed	User provided everything in initial prompt
2	PREPARE	Run flake detection + GDS alignment if microscope images provided; otherwise verify existing layout	No images provided / layout already prepared
3	ANALYZE	Study material regions, compute overlaps/exclusions, identify design-relevant zones	Never
4	DESIGN	Create device geometry via execute_script	Never
5	ROUTE	Use auto_route tool to connect device contacts to bonding pads	Device has no external contacts
6	EVALUATE	Run nanodevice DRC + metric evaluator, visually inspect failures, iterate	Never
7	SAVE	Export GDS + write result.json summary	Never

Each step has a gate condition. Maximum 2 retries per step. If a step fails after retries, report to the user.

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Step 1: QUERY

Check the user's initial prompt against this checklist. Only ask about missing items -- skip this step entirely if all required info is provided.

Parameter	Required?	Notes
Device type	Yes	What to build (Hall bar, FET, QD, etc.)
Material regions	Yes	Which layers have which materials, or microscope images to detect them
Layer assignments	Yes	Which layers to use for each design component
pixel_size	If images provided	Microns per pixel, needed for detection/alignment
Device-specific constraints	If any	Gates, contacts, pin count, dimensions
Output path	No	Defaults to source directory

Gate: All required parameters are known. Proceed.

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Step 2: PREPARE

Conditional step -- only runs if microscope images are provided.

If microscope images are provided:

1. Validate pixel_size via validate_pixel_size tool
2. Dispatch subagent to run nanodevice_flakedetect pipeline (align, detect, combine)
3. Dispatch subagent to run nanodevice_gdsalign if a GDS template is provided
4. Dispatch subagent to run nanodevice_flakedetect_commit to insert material polygons into KLayout

If starting from an existing layout:

• Verify expected material regions are present via get_layout_info

Gate: Material regions exist as polygons on their designated layers in KLayout.

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Step 3: ANALYZE

Prerequisite: Material contours must exist as polygons in KLayout, and any reference images must be loaded as background overlays. If they are not present, go back to PREPARE or ask the user.

The agent studies available geometry to inform design decisions:

1. Use get_layout_info to identify which layers have material regions
2. Use execute_script with pya.Region to compute overlaps, exclusions, bounding boxes
3. Use screenshot to visually inspect material regions and plan device placement
4. Identify which material zones are relevant for the specific device type

The agent derives material analysis logic from its physics knowledge of the device type. For example:

• A Hall bar needs graphene-graphite overlap for the channel
• A QD needs a gate-definable region
• A JJ needs a superconductor-insulator-superconductor stack

⚠️ Coordinate-frame contract (read before touching any flake coords)

If nanodevice_gdsalign has run, the flake polygons already committed in KLayout (the flake layers — L10-L13 by default, but confirm the mapping from your own commit) are in the GDS reference frame and are the single source of truth. Build the device against THOSE — read them back with pya.Region in absolute coordinates; do not re-derive flake geometry from raw JSON, and treat the committed flake layers as read-only reference (do not clear and re-insert flakes from an image-frame source).

• The ONLY valid JSON flake source after gdsalign is traces_gds.json → per-entry contour_gds. NEVER read contour_um (the un-warped image frame): it places the device hundreds of um off the GDS template and scores ~0 (the QH07 failure). Do not invent a device_geom.json with a hand-labeled frame.
• On session recovery (live layout empty / result.gds missing), rebuild flakes from traces_gds.json::contour_gds ONLY — never from contour_um.
• If the markers/flakes look off-frame, that is an alignment failure: re-run gdsalign (see its validated-commit contract), do not patch coordinates by hand.

Gate: The agent has identified where the device should be placed and what material constraints apply, working in the GDS reference frame (the committed L10-L13 flakes).

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Step 4: DESIGN

Create device geometry using execute_script. What to create depends on the device type -- the agent applies its physics knowledge:

• Design the active region (mesa, channel, dot, junction, etc.)
• Place contacts appropriate to the device type
• Place gates if needed (topgate, sidegate, backgate, split-gate, etc.)
• Ensure all components respect material region boundaries from ANALYZE

The skill does NOT prescribe dimensions, shapes, or layer numbers. The agent derives these from:

• Device type and physics requirements
• Available material regions from ANALYZE
• Layer assignments agreed in QUERY
• User-specified constraints

Use screenshot after each major geometry addition to visually verify placement.

Gate: Device geometry is present on designated layers. Visual inspection via screenshot confirms correct placement.

Frame guard (mandatory): before passing this gate, assert with pya.Region that the active region (mesa/channel) overlaps the material region the device physics requires — the SAME region you identified in ANALYZE (for a Hall bar that is the graphene∩graphite overlap; for a single-material device it is that one flake region; for a JJ/QD it is whatever its stack needs). Read those regions from the committed flake layers using the layer numbers YOU assigned (do not hard-code L11/L13 — confirm the mapping from your own commit). Procedure: (1) confirm the target flake layer(s) are non-empty — an absent material is a detection/commit problem, not a frame error, so skip the guard for it; (2) if the target region is non-empty but its overlap with the active region is empty, the device is in the wrong frame — STOP, fix the coordinate source (see the frame contract in ANALYZE) or re-run gdsalign, and do not proceed to ROUTE.

⚠️ Material-containment guard — contacts/arm-tips must land ON the flake (not just the mesa body)

The frame guard above only checks that the mesa body overlaps the flake. It does not catch a mesa whose probe arms / contact patches extend PAST the flake boundary — the central body still overlaps, so the frame guard passes, yet the arm-tip ohmic contacts sit in void and every material-keyed metric (contacts_in_regions, connectivity, mesa_probes, mesa_on_overlap) silently collapses. This is a distinct, common failure (it caps a structurally clean, correctly-framed device well below where it should score).

Principle — material-correctness outranks cosmetic shape. A device's contacts and the arm tips that carry them MUST sit inside the required flake region. Never lengthen a probe arm past the flake edge to satisfy a shape target (e.g. a low-solidity / "make the mesa concave" goal). Solidity, aspect ratio, and similar shape metrics are cosmetic and rank below keeping every contact on material. If the two conflict, shorten the arm and keep the contact on the flake.

Check before passing this gate (in addition to the frame guard): with pya.Region, intersect the contact-patch shapes (and the probe-arm tips, if separate) with the required flake region. If any contact patch's in-flake area fraction is below ~0.9, that arm is over-extended — pull it back so the patch is fully on the flake, then re-check. (Equivalently, once you have committed flakes you can run evaluate_design with arm_material_class / component_containment on the contact component and require a high fraction — the same measurement the official scorer makes.) Do not proceed to ROUTE while contacts hang off the flake.

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Step 5: ROUTE

If the device has contacts that need fan-out to bonding pads:

1. Place pin markers at contact positions via execute_script (on a temporary layer)
2. Place bonding pads if not already present (via execute_script)
3. Place pin markers at pad positions (on a temporary layer)
4. Call auto_route MCP tool with appropriate parameters:
   • pin_layer_a: contact pin layer
   • pin_layer_b: pad pin layer
   • output_layer: route layer
   • obstacle_layers: device geometry layers to avoid
   • Line width and safe distance as needed
   • For dense fan-out, use dry_run=true first to inspect the ordered-loop assignment, then use pin_pairs_override if the required device topology differs.
5. For failed pairs, write custom routing via execute_script
6. Clean up temporary pin marker layers

The agent decides routing topology, line widths, and obstacle avoidance based on device layout. The nanodevice_routing skill is available as a reference for multi-window EBL routing patterns, but is not required.

Gate: All contacts connected to bonding pads. No route crossings.

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Step 6: EVALUATE

Run the evaluate_design MCP tool as a nanodevice DRC + metric pass, with a check configuration composed by the agent based on what it designed.

Available check primitives:

Primitive	Args	Measures
component_overlap	component, region, region_op	Fraction of component area overlapping with region
component_containment	component, region, region_op	Fraction of component area contained within region
bulk_containment	component, bulk_region/materials, region_op, core_bbox	Fraction of a device body/core inside a caller-declared bulk region
arm_material_class	component, classes, containment_threshold	Fraction of shapes landing in exactly one material class
material_overlap_report	materials	Pairwise and multi-way material-region report
contact_isolation	component	Fraction of route pairs that don't cross (promotes crossing_pairs)
connectivity	contact_component, pad_component, route_component, tolerance	Fraction of contacts reaching pads
route_endpoints	route_component, target_components, tolerance	Fraction of route endpoints on valid targets
route_material_compat	(optional graphene/graphite keys)	Fraction of ohmic routes that stay OFF the opposing flake material (promotes violating_routes)
adjacency	component_a, component_b, tolerance	Fraction of A shapes within tolerance of B
solidity	component, threshold, direction	Shape solidity above/below threshold
spacing	component_a, component_b, min_distance	Fraction of pairs meeting min distance

The region arg can be a single layer_map key or a list of keys combined via region_op (union, intersection, difference).

Always include route_material_compat once routes exist (for devices with distinct ohmic materials, e.g. a Hall bar's graphene vs graphite contacts). A route that crosses the opposing flake material is an electrical short and is a common, easily-missed cause of a low score. The check returns violating_routes [{route_id, contact_kind, crossed_material, area_um2}] — reroute each violator (e.g. fan it out away from the opposing flake) and re-check, exactly as you use contact_isolation's crossing_pairs to fix route-route crossings.

Example check list for a Hall bar:

{
  "checks": [
    {"name": "component_containment", "args": {"component": "mesa", "region": ["graphene", "graphite"], "region_op": "intersection"}, "weight": 0.2},
    {"name": "adjacency", "args": {"component_a": "contact_patch", "component_b": "mesa", "tolerance": 2.0}, "weight": 0.15},
    {"name": "solidity", "args": {"component": "mesa", "threshold": 0.5, "direction": "below"}, "weight": 0.15},
    {"name": "contact_isolation", "args": {"component": "contact_route"}, "weight": 0.15},
    {"name": "connectivity", "args": {"contact_component": "contact_patch", "pad_component": "bonding_pad", "route_component": "contact_route"}, "weight": 0.15},
    {"name": "route_endpoints", "args": {"route_component": "contact_route", "target_components": ["contact_patch", "mesa", "bonding_pad"]}, "weight": 0.1},
    {"name": "spacing", "args": {"component_a": "contact_patch", "min_distance": 1.0}, "weight": 0.1}
  ]
}

Also take a screenshot for visual inspection.

• If score >= 0.80, proceed to SAVE
• If score < 0.80, identify lowest-scoring check and iterate
• Maximum 2 retries

Gate: Evaluation score >= 0.80 and visual inspection passes.

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Step 7: SAVE

BENCHMARK FORMAT WARNING: If this task is a benchmark run, the required result.json schema is defined in the task prompt itself. Re-read the task prompt and use the exact schema it specifies. Do NOT fall back to the nested general-purpose format below — a schema mismatch makes the evaluator score 0.0.

Save often — and make sure your BEST result is the one on disk

Follow the benchmark's own rule: save early, save often. A partial result always scores higher than no result; an agent that finishes a good device but times out before saving scores 0.0. So:

1. Save as soon as you have a complete, routed device, then re-save whenever you reach a higher EVALUATE score. Overwriting output/result.gds is free — save_layout writes it atomically (temp + rename), so a verifier never observes a half-written GDS; you do not need staging files.
2. Write result.json in the exact schema the task prompt specifies (it is usually a flat object with no score field — do not add one). Keep it in sync with the saved GDS.
3. Don't let a later, worse iteration become the final artifact. Only re-save when EVALUATE confirms the new design is at least as good; if an experiment makes things worse, revert the geometry before the next save.
4. Confirm the save landed. Read back output/result.gds size / get_layout_info. If a tool returns a suspicious, stale, or repeated result (a wedged bridge), call ping to check the server is alive, then re-save.

1. Save your BEST design atomically per the save-best block above (stage .new, promote both with one mv).
2. Write result.json — check if the task or benchmark specifies a required format first and use that exactly. If no format is specified, use this general-purpose default:

General format (non-benchmark):

• device_type: from QUERY
• layer_map: all layer assignments used (e.g. {"mesa": [{"layer": 20, "datatype": 0}], ...})
• score: final evaluation score from EVALUATE
• pixel_size: if applicable
• pipeline_status: per-step pass/fail/retry counts
• checks: the evaluation check configuration used
• feedback: design notes and any user interventions

Gate: GDS file written and result.json contains all required fields.

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Retry Protocol

Maximum 2 retries per step. When a gate fails:

Failed Step	Retry Action
PREPARE	Re-run detection with adjusted parameters
ANALYZE	Re-inspect with different region computations
DESIGN	Redesign failing component based on gate feedback
ROUTE	Re-route with adjusted parameters or manual fallback
EVALUATE	Re-run failing design sub-step per lowest-scoring check

If any step exhausts retries, stop and report to the user.

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MCP Wedged? Restart KLayout

MCP is the only path by design -- there is no standalone subprocess fallback. If an MCP call hangs, times out, or stops responding partway through the pipeline, the recovery is to restart KLayout, not to route around it.

Don't stand and wait. Restart KLayout:

1. pkill -f klayout -- kill any running KLayout processes.
2. open /Applications/klayout.app -- relaunch (standalone command; do not chain with &&).
3. Poll http://127.0.0.1:8765/mcp until the server responds (typically 5-10 s after launch).
4. Re-run the failed call.

Keeping MCP as the single canonical path forces real bugs to surface instead of being masked by a fallback. After the restart, resume the pipeline from the step that was in flight when the call wedged -- earlier completed steps remain valid in the saved layout if the layout was checkpointed; otherwise, restart from the last gate that was satisfied.

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What This Skill Prescribes

• Step ordering (QUERY -> PREPARE -> ANALYZE -> DESIGN -> ROUTE -> EVALUATE -> SAVE)
• Gate conditions before proceeding
• Retry protocol (max 2 per step)
• Which MCP tools to use: execute_script, auto_route, evaluate_design, screenshot, get_layout_info, save_layout, validate_pixel_size
• Query checklist for completeness

What This Skill Does NOT Prescribe

• Specific device geometries or dimensions
• Specific layer numbers (agreed with user)
• Specific material assumptions (agent derives from device type)
• Specific evaluation weights (agent composes per device)
• Specific routing topology (agent decides)

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Conventions

• Conda env: instrMCPdev (has opencv, numpy, scipy, sklearn, shapely, gdstk)
• Pixel coordinates: image origin at top-left; KLayout uses center origin with Y-flip
• Layer references: always as layer/datatype (e.g., 11/0)
• Output directory: defaults to source image directory if not specified
• Sub-skill dispatch: flakedetect and gdsalign sub-skills run as subagents reading their own SKILL.md