schematic-reader

name	schematic-reader
description	Search schematic PDFs by text/OCR, then confirm details with region crops and OCR — not full-page re-reads.
metadata	{"sylo":{"category":"documents","icon":"file-search"}}

Schematic reader workflow

Use targeted search → region crop + OCR → brief answer. Full-page renders locate the sheet; region tools read wire numbers and terminal labels.

Industry pattern (engineering-drawing pipelines): detect/crop regions first, then run vision/OCR on the crop — full-page passes garble small text and invite hallucination.

Tools

Tool	When
search_schematic_pdf	Always first — locate pages; render_on_best_hit: true for a coarse full-page PNG
render_schematic_page	Know the page; need layout context (one call only)
render_schematic_region	Wire numbers / terminal labels too small on full page — default 300 DPI crop
ocr_schematic_region	Deterministic text tokens near a terminal block; pass queries for wire/tag numbers

Specific questions (wire, cable, port, tag)

1. Narrow search — 1–3 queries from the question (e.g. ["DGT-300+", "S-"]). Do not re-scan the whole drawing set.
2. Snippets locate pages only. PDF text is often garbled — never treat snippet order as terminal wiring.
3. One full-page look — at most one render_schematic_page (or render_on_best_hit) per question to find the area. If small text is unreadable, stop re-examining that PNG.
4. Region next — render_schematic_region + ocr_schematic_region on the same bbox (normalized 0–1 fractions of page). Example bbox around lower-right detail: {"x0":0.55,"y0":0.35,"x1":0.98,"y1":0.85}.
5. Cross-check — prefer answers where OCR matched_tokens and region vision agree. If they disagree, widen bbox or raise dpi once — do not loop.
6. Brief answer — 2–4 sentences or a short table. State verification level (see below).

Anti-rumination (required)

• One look per unique image path — never re-reason over the same PNG/DPI/bbox.
• No hypothesis recycling — if you already guessed an answer from color codes or pinout, do not re-derive it in later thinking; either verify with region OCR or label it Inferred.
• Budget per question: ≤1 full-page render, ≤2 region render/OCR pairs, ≤3 search_schematic_pdf calls.
• When stuck: ask one clarifying question or report what OCR/vision could not read — do not spend minutes on the same page.

Answer calibration (required)

Tag every wire/tag answer:

Level	When to use
Verified (schematic)	OCR matched_tokens clearly show the wire at the terminal, or region crop vision unambiguously shows the label
Inferred (convention)	Color code, standard pinout, or industry practice — not read from the drawing
Unreadable	Region OCR empty and region vision ambiguous — say so; do not guess

Never present Inferred as Verified. Example: "1242 (Verified — OCR on Actual Value S- terminal)" vs "likely 1242 (Inferred — WHITE is often S- on 4-wire cells; OCR did not confirm)".

Survey / attached PDF (“what’s in this?”)

• Broader query list is fine to prove the tool and build a sheet index.
• JSON includes page_count and hit_count. hits is capped by max_results (default 8).
• No region renders until the operator asks a detail question.

Parameters

• bbox — {x0,y0,x1,y1} or [x0,y0,x1,y1] as fractions of page size (0–1). Use padding: 0.02 if labels clip.
• render_schematic_region / ocr_schematic_region — default 300 DPI on the crop.
• ocr_schematic_region.queries — e.g. ["1242", "S-", "1240"] to surface wire numbers in matched_tokens.
• use_ocr: true on search — scanned PDFs with empty text layer.
• Cached PNGs: .schematic-reader/ beside the PDF.

Rules

• Never render all pages.
• Never re-read the same full-page image hoping clarity improves.
• Snippets locate pages; region OCR + crop vision confirm numbers.

Examples

Wire to terminal: “What wire goes to S- on DGT-300+?”

{
  "pdf_path": ".../drawing.pdf",
  "query": ["DGT-300+", "S-"],
  "render_on_best_hit": true
}

Then region on page from top hit:

{
  "pdf_path": ".../drawing.pdf",
  "page": 14,
  "bbox": { "x0": 0.5, "y0": 0.4, "x1": 0.98, "y1": 0.88 },
  "queries": ["1240", "1241", "1242", "1243", "S-"]
}

Run ocr_schematic_region with the same page/bbox/queries. Answer from matched_tokens when confident; otherwise Unreadable or Inferred with explicit label.

Survey: attached PDF → index queries, max_results: 12, no render until a detail question.