qyl

Question Your Logs — AI Observability Platform

Landing page: https://ancplua.github.io/qyl/

What qyl Does

Collects	OTLP receiver with idempotent ingestion (retry-safe)
Instruments	Roslyn source generators for zero-config GenAI telemetry
Visualizes	Real-time dashboard with SSE streaming
Integrates	MCP server and GitHub Copilot for AI agent observability

Tech Stack

Layer	Technology
Runtime	.NET 10.0 LTS, C# 14
Frontend	React 19, Vite 7, Tailwind CSS 4
Storage	DuckDB (columnar, upsert-based)
Protocol	OpenTelemetry 1.40 GenAI Semantic Conventions
Schema	TypeSpec → OpenAPI → C#/DuckDB/TypeScript

Components

Package	Purpose
qyl.collector	OTLP receiver, DuckDB storage, REST API, embedded dashboard
qyl.copilot	GitHub Copilot integration with AG-UI tool rendering
qyl.hosting	App orchestration framework (QylRunner)
qyl.servicedefaults	.NET instrumentation library with OTel setup
qyl.servicedefaults.generator	Roslyn source generator for GenAI/DB interceptors
qyl.instrumentation.generators	DuckDB insert + interceptor source generators
qyl.mcp	MCP server for AI agent integration
qyl.protocol	Shared types (BCL-only, no dependencies)

Quick Start

Hosted

https://qyl-api-production.up.railway.app

Docker

docker build -f src/qyl.collector/Dockerfile -t qyl .
docker run -d -p 5100:5100 -p 4317:4317 -v ~/.qyl:/data qyl

From Source

git clone https://github.com/ANcpLua/qyl.git
cd qyl
dotnet run --project src/qyl.collector

Instrument Your .NET App

Add the service defaults package to automatically instrument GenAI calls:

// Program.cs
builder.AddQylServiceDefaults();

This auto-instruments:

• IChatClient calls (Microsoft.Extensions.AI)
• Token usage, latency, model info
• Full OTel 1.40 GenAI semantic conventions

Set the exporter endpoint:

export OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:5100"

Use with Any OTel App

qyl accepts standard OTLP from any language/framework:

# Point any OpenTelemetry SDK at qyl
export OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:5100"
export OTEL_EXPORTER_OTLP_PROTOCOL="http/protobuf"

Supported protocols:

• OTLP/HTTP (port 5100)
• OTLP/gRPC (port 4317)

Architecture

+------------------+                     +------------------+
|  Your .NET App   |                     |  Any OTel App    |
| (servicedefaults)|                     |  (Python, Go..)  |
+--------+---------+                     +--------+---------+
         |                                        |
         |               OTLP                     |
         +----------------+-----------------------+
                          v
            +----------------------------+
            |       qyl.hosting          |
            |      (QylRunner)           |
            +-------------+--------------+
                          | orchestrates
                          v
            +----------------------------+
            |       qyl.collector        |
            |        (ASP.NET)           |
            +---+------+------+-----+---+
                |      |      |     |
      +---------+  +---+---+  |  +--+--------+
      v            v       v  |  v            v
+----------+ +----------+ |  | +----------+ +----------------+
|  DuckDB  | | Dashboard| |  | |   MCP    | |  qyl.copilot   |
| (storage)| | (React)  | |  | | (agents) | | (GitHub Copilot)|
+----------+ +----------+ |  | +----------+ +-------+--------+
                           |  |                      |
                     +-----+--+-----+          SSE / AG-UI
                     | Insights     |                |
                     | Materializer |                v
                     +--------------+        GitHub Copilot

AG-UI Tool Rendering

qyl.copilot exposes observability tools to GitHub Copilot via SSE streaming with AG-UI event conventions.

Tools (via ObservabilityTools):

Tool	Description
search_spans	Search spans by service name, status, time range
get_trace	Get all spans for a trace ID
get_genai_stats	GenAI usage statistics (requests, tokens, costs)
search_logs	Search logs by severity, body text, time range
get_storage_stats	Storage statistics (span/log/session counts, size)
list_sessions	List spans belonging to a session
get_system_context	Pre-computed system context (zero query cost)

Each tool is wrapped by DelegatingAIFunction which applies CopilotMetrics (counters, histograms) and CopilotInstrumentation (OTel spans).

Endpoints:

Method	Path	Purpose
POST	/api/v1/copilot/chat	Chat (SSE streaming)
GET	/api/v1/copilot/workflows	List workflows
POST	/api/v1/copilot/workflows/{name}/run	Execute workflow (SSE)
GET	/api/v1/copilot/status	Auth status
GET	/api/v1/copilot/executions	Execution history
GET	/api/v1/copilot/executions/{id}	Execution details

SSE events use AG-UI convention: tool_call and tool_result event names.

Insights Materializer

Background service that pre-computes system context every 5 minutes (10-second warmup delay).

Materializer	Computes
TopologyMaterializer	Service discovery, AI model usage
ProfileMaterializer	Latency percentiles (P50/P95/P99), token costs, trends
AlertsMaterializer	Error spikes, cost drift, slow operations

Results are stored in the materialized_insights table and served via get_system_context with zero query cost at read time.

Ports

Port	Protocol	Purpose
5100	HTTP	REST API, Dashboard, OTLP/HTTP
4317	gRPC	OTLP/gRPC ingestion

Environment Variables

Variable	Default	Purpose
QYL_PORT	5100	HTTP API port
QYL_GRPC_PORT	4317	gRPC OTLP port (0=disable)
QYL_DATA_PATH	./qyl.duckdb	DuckDB file location
QYL_TOKEN	(none)	Auth token
QYL_MAX_RETENTION_DAYS	30	Telemetry retention
QYL_MAX_SPAN_COUNT	1000000	Max spans before cleanup
QYL_MAX_LOG_COUNT	500000	Max logs before cleanup
QYL_CLEANUP_INTERVAL_SECONDS	300	Cleanup interval
QYL_OTLP_CORS_ALLOWED_ORIGINS	*	CORS origins (CSV)

GenAI Telemetry

qyl captures OpenTelemetry 1.40 GenAI semantic conventions:

Attribute	Description
gen_ai.provider.name	Provider (openai, anthropic, etc)
gen_ai.request.model	Model name
gen_ai.usage.input_tokens	Prompt tokens
gen_ai.usage.output_tokens	Completion tokens
gen_ai.response.finish_reasons	Stop reason

TypeSpec-First Design

All types are defined in TypeSpec and generated downstream:

core/specs/*.tsp
       ↓ (tsp compile)
core/openapi/openapi.yaml
       ↓ (nuke Generate)
   ┌───┴───┬───────┬────────┐
   ↓       ↓       ↓        ↓
  C#    DuckDB    TS    JSON Schema

Never edit *.g.cs or api.ts — edit TypeSpec and regenerate.

Idempotent Ingestion

Spans use ON CONFLICT (span_id) DO UPDATE — SDKs can safely retry on network errors without creating duplicates. Mutable fields (tokens, status, cost) are updated; immutable fields (trace_id, name, start_time) are preserved.

Development

# Full build (TypeSpec → Docker)
nuke Full

# Regenerate types from TypeSpec
nuke Generate --force-generate

# Run tests
dotnet test

# Dashboard dev server (hot reload)
cd src/qyl.dashboard && npm run dev

# Collector only
dotnet run --project src/qyl.collector

Project Structure

core/                                   # TypeSpec schemas (source of truth)
eng/                                    # NUKE build system
src/
  qyl.collector/                        # Backend API service
  qyl.copilot/                          # GitHub Copilot integration (AG-UI)
  qyl.dashboard/                        # React frontend
  qyl.hosting/                          # App orchestration (QylRunner)
  qyl.mcp/                             # MCP server
  qyl.protocol/                         # Shared types (BCL-only)
  qyl.servicedefaults/                  # OTel instrumentation library
  qyl.servicedefaults.generator/        # Roslyn source generator
  qyl.instrumentation.generators/       # DuckDB insert + interceptor generators
tests/                                  # Test projects

License

MIT