Configuration

The Extractor and Interpreter add cratis-prologue.json through the shared Cratis.Prologue.Configuration package. The Extractor binds capture settings under prologue and YARP’s reverseProxy section. Batch interpretation binds llm; service interpretation also binds prologue.mongo. The Receiver uses standard ASP.NET configuration, including appsettings.json and environment variables, and binds prologue.mongo.

Where the file comes from

• The Extractor and Interpreter look for cratis-prologue.json in their working directory. Override the path with PROLOGUE_CONFIG, or pass another base path when calling AddPrologueConfiguration() in a custom host.
• The file is the baseline; environment variables override it. Properties have double-underscore environment equivalents such as Prologue__Output__Kind, Prologue__SqlServer__0__ConnectionString, and ReverseProxy__Clusters__monitored__Destinations__primary__Address.
• The Receiver follows standard ASP.NET precedence instead. Configure MongoDB in its appsettings.json or with Prologue__Mongo__ConnectionString, Prologue__Mongo__Database, and Prologue__Mongo__Collection.
• A missing cratis-prologue.json is allowed; type defaults and environment variables still apply.

Root shape

Property	Type	Purpose
prologue	PrologueOptions and storage options	Capture sources, correlation, output, and MongoDB storage for the applicable host
llm	LlmOptions	Optional language-model refinement bound by the Interpreter
reverseProxy	YARP configuration	Routes and clusters for the HTTP capture source — see YARP’s configuration docs

prologue

Property	Type	Default	Purpose
prologueId	guid	empty guid	Associates captures with one interpretation session when explicitly configured
output	OutputOptions	—	Where captures are written
correlation	CorrelationOptions	—	The correlation time window
sqlServer	array of SqlServerOptions	[]	SQL Server databases to watch via CDC
postgres	array of PostgresOptions	[]	PostgreSQL databases to watch via logical replication
openTelemetry	OpenTelemetryOptions	—	OTLP proxy configuration
mongo	MongoOptions	—	Capture and service-session storage used by the Receiver and service Interpreter

prologue.output

Property	Type	Default	Purpose
kind	"Api" | "Json"	"Api"	Whether captures are posted to a Receiver or written to JSON files
api.endpoint	string	"http://localhost:5005"	Receiver base address, used when kind is "Api"
json.directory	string	"./captures"	Folder to write rolling .jsonl capture files to, used when kind is "Json"
json.maxEntriesPerFile	int	10000	Entries per file before the Extractor rolls to a new one

prologue.correlation

Property	Type	Default	Purpose
windowMilliseconds	int	2000	How long after a command the correlator keeps grouping database transactions and telemetry into the same capture — see How Prologue works

prologue.sqlServer[]

Property	Type	Default	Purpose
name	string	"sqlserver"	Label for this database in captures
connectionString	string	—	Connection string; needs permission to enable CDC
enableChangeDataCapture	bool	true	Whether the Extractor enables CDC on the database itself
tables	array of string	[]	Table allowlist; empty captures every user table
pollIntervalMilliseconds	int	500	How often the Extractor polls for new CDC changes

prologue.postgres[]

Property	Type	Default	Purpose
name	string	"postgres"	Label for this database in captures
connectionString	string	—	Connection string; needs permission to create a replication slot and publication, and wal_level = logical on the server
slot	string	"prologue_slot"	Replication slot name
publication	string	"prologue_publication"	Publication name

prologue.openTelemetry

Property	Type	Default	Purpose
enabled	bool	false	Whether the OTLP proxy is active
serviceNames	array of string	[]	Service name allowlist; empty captures telemetry from every service
attributeKeys	array of string	[]	Attribute keys whose values are captured; all observed keys remain visible while other values are dropped
upstream.http	string	—	Upstream OTLP/HTTP collector to forward telemetry to
upstream.grpc	string	—	Upstream OTLP/gRPC collector to forward telemetry to

Leave both upstream addresses empty to make the Extractor a terminal collector rather than a forwarding proxy.

prologue.mongo

The Receiver and service-mode Interpreter bind these settings through Cratis.Prologue.Storage. The service also stores interpretation checkpoints in the configured database.

Property	Type	Default	Purpose
connectionString	string	"mongodb://localhost:27017"	MongoDB connection used for captures and service checkpoints
database	string	"Prologue"	Database containing Prologue collections
collection	string	"captures"	Capture collection used by the Receiver and Interpreter

llm

Property	Type	Default	Purpose
enabled	bool	false	Whether the Interpreter refines the heuristic model with a language model
kind	"Ollama" | "OpenAI" | "AzureOpenAI" | "OpenAICompatible" | "Anthropic"	"Ollama"	Which provider to call
endpoint	string	"http://llm:11434"	Provider endpoint; the hosted providers (OpenAI, Azure OpenAI, Anthropic) default to their public endpoint if you don’t set one
accessToken	string	—	API key for the hosted providers; not needed for a local Ollama endpoint
modelId	string	an Ollama model tag	The model to call — for AzureOpenAI, this is the deployment name, not a model name
refinementTimeout	duration	2 minutes	How long the Interpreter waits for a refinement response before giving up and keeping the heuristic result

See Running the Interpreter for a worked example.

Next

• Capture sources — what triggers a capture per source.
• Point Prologue at your system — a complete worked cratis-prologue.json.