kandev/docs/specs/platform/startup-configuration-parity.md

status, created, owner

status	created	owner
shipped	2026-08-20	kandev

Startup Configuration Parity

Why

Kandev has two startup configuration paths. Some settings use typed YAML and environment variables. Other settings read only environment variables at their consumer. Operators must then maintain service-specific environment setup even when they already use config.yaml.

This split also causes inconsistent launcher behavior. For example, the launcher can replace a database path that the backend would otherwise read from YAML. A stable configuration contract must apply before the launcher starts the backend and continue through every managed process.

What

Kandev gives every stable, operator-facing startup setting a canonical YAML key. Each setting keeps its current environment variable as a compatible override.

The effective startup precedence is:

1. A command-line launch flag, when that setting has one.
2. An explicit environment variable.
3. The selected config.yaml value.
4. The existing built-in or profile default.

For settings that also have a database override, the environment variable and YAML value both take precedence over the database value. The full order is environment variable, YAML, database override, then profile or built-in default.

Kandev selects the first existing configuration file in this order:

1. config.yaml in the process working directory.
2. <KANDEV_HOME_DIR>/config.yaml, or ~/.kandev/config.yaml when the home directory has no explicit override.
3. /etc/kandev/config.yaml.

Kandev does not merge these files. If the first existing candidate is invalid or unreadable, startup fails and reports that file. Kandev does not continue to a lower-priority candidate.

The home directory is bootstrap configuration. A launch flag or the explicit KANDEV_HOME_DIR environment variable selects it before Kandev searches for the home configuration file. A configuration file in the working directory or in /etc/kandev can set homeDir. The selected home configuration file cannot use homeDir to relocate itself.

Configuration changes require a restart. Kandev does not watch configuration files.

Canonical additions

The existing typed configuration keys remain canonical. The following stable environment-only settings gain YAML keys:

YAML key	Type and valid YAML value	Default	Compatible environment variable
server.trustedProxies	List of valid IP or CIDR strings	Empty list	KANDEV_TRUSTED_PROXIES
tasks.preparationTimeout	Positive Go duration string	10m	KANDEV_TASK_PREPARATION_TIMEOUT
credentials.file	File path string. Empty disables the provider.	Empty	KANDEV_CREDENTIALS_FILE
limits.ghMaxConcurrent	Positive integer	8	KANDEV_GH_MAX_CONCURRENT
limits.gitMaxConcurrent	Positive integer	12	KANDEV_GIT_MAX_CONCURRENT
limits.lspMaxConnections	Positive integer	8	KANDEV_LSP_MAX_CONNECTIONS
messageQueue.maxPerSession	Integer of zero or greater. Zero disables the cap.	10	KANDEV_QUEUE_MAX_PER_SESSION
agentctl.idleTimeout	Nonnegative Go duration string. Zero disables reaping.	1h	KANDEV_ACP_IDLE_TIMEOUT
agentctl.idleReaperInterval	Positive Go duration string	1m	KANDEV_ACP_IDLE_REAPER_INTERVAL
agentctl.notificationQueueCapacity	Integer from 1024 through 131072	131072	KANDEV_ACP_NOTIF_QUEUE
planning.coalesceWindowMs	Integer of zero or greater	300000	KANDEV_PLAN_COALESCE_WINDOW_MS
office.schedulerTickMs	Positive integer	5000	KANDEV_OFFICE_SCHEDULER_TICK_MS
observability.otlpEndpoint	Endpoint string. Empty disables tracing.	Empty	OTEL_EXPORTER_OTLP_ENDPOINT
launcher.webPort	Integer from 1 through 65535, or absent for automatic selection	Automatic	KANDEV_WEB_PORT
launcher.healthTimeoutMs	Positive integer	45000 in release, 600000 in dev	KANDEV_HEALTH_TIMEOUT_MS
launcher.noBrowser	Boolean	false	KANDEV_NO_BROWSER

YAML uses native lists, integers, and booleans as shown above. Duration values use strings so their units remain visible. The trusted proxy environment value keeps its comma-separated syntax. Numeric and boolean environment values keep their current string syntax and compatibility parsing.

The launcher also honors the existing YAML keys homeDir, server.host, server.port, database.path, and logging.level. server.port is the YAML equivalent for KANDEV_BACKEND_PORT, compatibility variable KANDEV_PORT, and the internal backend port handoff.

The published configuration reference lists every supported stable startup environment variable. Each row names its YAML equivalent or a justified exclusion.

Stable secrets

Stable startup secrets get the same YAML parity as other stable startup settings. This includes existing typed database, authentication, and office secrets. It does not include credentials that users manage in the product UI or database.

Kandev never logs secret values. On Unix systems, Kandev warns when the selected configuration file contains a secret and group or other users can read it. The warning does not block startup. Public guidance recommends owner-only mode 0600 and an environment-based secret manager where available.

Configuration ownership

One typed configuration catalog maps stable operator settings to YAML keys, environment variables, defaults, sensitivity, and owning runtime component. Completeness tests prevent a stable setting from bypassing this catalog.

Kandev does not copy YAML values into public process environment variables. The launcher reads the bootstrap subset from the same catalog. The backend loads the full typed configuration. Managed agentctl processes receive the resolved settings that they own through explicit startup configuration.

Message queue source

When messageQueue.maxPerSession comes from YAML, the Settings UI treats it as an operator lock. The API reports configuration as the source. The UI names the configuration file as the source and does not claim that an environment variable set the value.

The existing responsive Settings layout remains unchanged. Desktop and mobile users receive the same source and lock behavior.

Failure modes

Condition	Behavior
No configuration candidate exists	Kandev starts with environment, profile, and built-in values.
The first existing candidate is unreadable	Startup fails and names the selected file.
The first existing candidate has invalid YAML or an invalid typed value	Startup fails and names the setting and file.
A legacy environment value is invalid	Kandev keeps that setting's current compatibility behavior.
A home configuration file contains homeDir	Startup fails with a relocation error.
A configuration file contains a secret and has broad Unix read permissions	Kandev warns without revealing the value, then continues.
A managed agentctl process cannot receive valid resolved configuration	Its launch fails instead of silently using a different value.

Scenarios

• GIVEN ~/.kandev/config.yaml contains server.trustedProxies, WHEN Kandev starts behind the listed proxy, THEN it trusts forwarded headers from that proxy without an environment variable.
• GIVEN YAML and an environment variable set the same option, WHEN Kandev starts, THEN the environment value wins.
• GIVEN a launch flag, environment variable, and YAML set the backend port, WHEN Kandev starts, THEN the launch flag wins.
• GIVEN working-directory, home, and system configuration files exist, WHEN Kandev starts, THEN it reads only the working-directory file.
• GIVEN the working-directory file is absent and the home file exists, WHEN Kandev starts, THEN it reads only the home file.
• GIVEN the first existing file is invalid, WHEN Kandev starts, THEN startup fails without reading a lower-priority file.
• GIVEN database.path is set in the selected file, WHEN the launcher starts the backend, THEN the backend uses that path.
• GIVEN a stable startup secret is set in YAML, WHEN Kandev starts, THEN the owning component receives it and logs do not expose it.
• GIVEN a secret-bearing file is readable by other users on Unix, WHEN Kandev loads it, THEN the logs contain a permission warning without the secret value.
• GIVEN messageQueue.maxPerSession is set in YAML, WHEN a desktop or mobile user opens Message Queue settings, THEN the field is locked and identifies configuration as its source.
• GIVEN agentctl timeout or tracing settings are set in YAML, WHEN Kandev launches agentctl through a supported executor, THEN that process uses the resolved values.
• GIVEN an internal, generated, test, or debug-only environment variable, WHEN the configuration completeness test runs, THEN its recorded exclusion satisfies the catalog without creating a public YAML key.

Out of scope

• A .env file loader.
• A public --config flag.
• Merging multiple configuration files.
• Live reload or a file watcher.
• A Settings UI editor for startup configuration.
• YAML keys for profile selectors, mocks, E2E controls, or debug-only controls.
• YAML keys for generated tokens, launcher-to-child wiring, packaging metadata, bundle discovery, workspace or session injection, or deprecated no-op values.
• YAML keys for credentials managed in the product UI or database.
• Replacing standard platform detection when an existing typed setting already controls the result, such as DOCKER_HOST with docker.host.

Decision: Startup configuration uses one typed source model.