# Universal Sign Language Dictionary (USL)

USL is the PlatPhormNews public universal-symbol and signage reference layer.

- Base URL: https://usl.platphormnews.com
- Symbols: 204 canonical records
- Categories: 15 canonical categories
- Public access: homepage, symbol browsing, search, filtering, Learn, Quiz, Statistics, API docs, OpenAPI, llms, RSS/feed, sitemap, and read-only MCP introspection
- Auth: public-safe Phase 1 reads do not require a key; future protected backend actions use PLATPHORM_API_KEY only
- Storage: static canonical symbol/category data; quiz progress and favorites are browser-local where used
- Scope: universal public symbols, accessibility icons, public signage, wayfinding, safety, transportation, facilities, commerce, medical, environment, communication, emoji-adjacent symbols, and cross-cultural visual communication
- Safety: USL is not a full signed-language interpreter and does not replace natural signed languages
- Emoji integration: 192 symbols have emoji.platphormnews.com links; standalone public symbols are labeled
- Standards: ISO 7001, Unicode, and IEC 60417 reference links are included; official inclusion is claimed only when canonical data has a matching code
- Model support: degraded; no invented AI output is generated
- MCP endpoint: https://usl.platphormnews.com/api/mcp
- API docs: https://usl.platphormnews.com/api/docs
- OpenAPI: https://usl.platphormnews.com/openapi.yaml
- RSS: https://usl.platphormnews.com/rss.xml
- Sitemap: https://usl.platphormnews.com/sitemap.xml
- Trace: W3C trace context and safe PlatPhorm trace headers are accepted and emitted on API/MCP/cron responses


## Categories
- Transportation (transportation): 17 symbols
- Accessibility (accessibility): 12 symbols
- Safety & Warning (safety-warning): 20 symbols
- Information (information): 13 symbols
- Facilities (facilities): 18 symbols
- Wayfinding (wayfinding): 12 symbols
- Technology (technology): 12 symbols
- Commerce (commerce): 12 symbols
- Medical (medical): 14 symbols
- Environment (environment): 14 symbols
- Prohibition (prohibition): 15 symbols
- Food & Beverage (food-beverage): 12 symbols
- Communication (communication): 11 symbols
- Weather & Nature (weather-nature): 12 symbols
- Sports & Recreation (sports-recreation): 10 symbols

## API Endpoints
- GET /api/health: Public health summary
- GET /api/v1/health: Public health summary with API envelope
- GET /api/docs: Public API documentation
- GET /openapi.yaml: OpenAPI YAML
- GET /openapi.json: OpenAPI JSON
- GET /api/v1/symbols: List canonical symbols
- GET /api/v1/symbols/{slug}: Get one canonical symbol
- GET /api/v1/categories: List canonical categories
- GET /api/v1/categories/{slug}: Get one canonical category
- GET /api/v1/search: Search canonical symbols
- GET /api/v1/quiz: Quiz capability and local-progress policy
- GET /api/v1/quiz/questions: Generate public-safe quiz questions from canonical symbols
- POST /api/v1/quiz/score: Score a quiz attempt without server persistence
- GET /api/v1/statistics: Canonical data statistics
- GET /api/v1/standards: Reference standards
- GET /api/v1/integrations/emoji: Emoji-linked symbols
- GET /api/v1/integrations/status: Cross-site integration status
- GET /api/mcp: MCP metadata and usage
- POST /api/mcp: MCP JSON-RPC 2.0 endpoint

## MCP Tools
- list_symbols
- get_symbol
- search_symbols
- list_categories
- get_category
- list_standards
- get_statistics
- generate_quiz
- score_quiz
- get_emoji_links
- explain_symbol
- get_health
- get_info
- get_route_compliance
- get_discovery_compliance
- create_docs_report
- create_sheet_report
- create_deck_summary

## MCP Resources
- usl://symbols
- usl://symbol/{slug}
- usl://categories
- usl://category/{slug}
- usl://standards
- usl://quiz
- usl://statistics
- usl://emoji-links
- usl://faq
- usl://openapi
- usl://llms
- usl://trust-policy

## MCP Prompts
- explain_universal_symbol
- generate_symbol_quiz
- compare_symbols
- explain_wayfinding_symbol
- explain_accessibility_symbol
- create_usl_learning_plan
- generate_symbol_reference_card
- human_machine_usl_handoff

## Learning Topics
- Universal Symbols Are Visual References: USL catalogs public symbols, accessibility icons, signage patterns, and emoji-adjacent symbols. It does not replace natural signed languages.
- Standards References: ISO, Unicode, and IEC links are reference links. A symbol is only described as linked to a standard when the canonical record contains that code.
- Accessibility And Wayfinding: Accessible labels, alt text, usage notes, and category filters help humans and agents understand the intended public context.