Configuration Reference

All configuration lives in .ninety-nine.toml at the project root. Every field has a default value – you only need to specify overrides.

`[detection]`

Controls how tests are discovered and analyzed.

Field	Type	Default	Description
`min_runs`	u32	`10`	Minimum number of runs per test
`confidence_threshold`	f64	`0.95`	Confidence level required to classify as flaky
`window_size`	u32	`100`	Number of recent runs used for trend analysis
`parallel_runs`	u32	`3`	Number of concurrent test executions

Detection uses Beta distribution posterior inference with conjugate priors. A test is only ever classified as flaky once at least one failure has actually been observed; long histories of clean passes always classify as stable.

`[detection.duration_regression]`

Optional configuration for detecting tests whose execution time has significantly increased.

Field	Type	Default	Description
`enabled`	bool	–	Enable duration regression detection
`min_history_runs`	u32	–	Minimum historical runs required before checking
`threshold`	enum	–	How to determine a regression (see below)

When the section is omitted entirely, the check runs with its long-standing defaults: a 10-run history requirement and a threshold of 2 standard deviations. Provide the section to tune those values, or set enabled = false to switch the check off:

[detection.duration_regression]
enabled = true
min_history_runs = 10

# Option A: flag when latest duration exceeds N standard deviations above the mean
[detection.duration_regression.threshold]
StdDev = 2.0

# Option B: flag when latest duration exceeds mean * multiplier
# [detection.duration_regression.threshold]
# Multiplier = 3.0

Threshold variants:

Variant	Description
`StdDev(f64)`	Flag when the latest duration is more than N standard deviations above the historical mean
`Multiplier(f64)`	Flag when the latest duration exceeds the historical mean multiplied by this factor

`[diagnose]`

Controls the multi-phase diagnose command (stress / isolation / optional rr).

Field	Type	Default	Description
`stress_runs`	u32	`3`	Full-binary multi-threaded suite iterations
`isolation_runs`	u32	`10`	Serial isolation iterations per candidate
`stress_threads`	u32	`0`	libtest threads (0 = host parallelism)
`stress_timeout_secs`	u64	`300`	Timeout per stress binary iteration
`record`	bool	`false`	Attempt rr recording for Intrinsic failures
`record_dir`	path	`.ninety-nine/recordings`	rr output directory
`record_attempts`	u32	`10`	Max rr attempts per Intrinsic candidate
`chaos`	bool	`false`	Pass `--chaos` to rr when recording

`[detection]` multi-phase

Field	Type	Default	Description
`multi_phase`	bool	`false`	When true, `test` runs diagnose for candidates then Bayesian suite for the rest

`[quarantine.by_class]`

Field	Type	Default	Description
`intrinsic`	bool	`true`	Auto-quarantine Intrinsic diagnose classes
`contention`	bool	`false`	Auto-quarantine Contention classes
`broken`	bool	`true`	Auto-quarantine Broken classes

`[retry]`

Controls retry behavior when tests fail.

Field	Type	Default	Description
`unit_test_retries`	u32	`2`	Number of retries for failed tests
`backoff_strategy`	enum	`Exponential`	Backoff strategy between retries
`max_retry_time_secs`	u64	`300`	Time limit for a single test execution (seconds)

Every attempt is recorded as its own run, so a test that fails and then passes on retry contributes both outcomes to its flakiness score — recovery on retry is itself flaky evidence, and raising the retry count therefore gathers more evidence per iteration rather than hiding failures.

Backoff Strategies

# No delay between retries
[retry]
backoff_strategy = "None"

# Fixed delay
[retry.backoff_strategy]
Linear = { delay_ms = 200 }

# Exponential backoff (default: base_ms=100, factor=2.0, max_ms=5000)
[retry.backoff_strategy]
Exponential = { base_ms = 100, factor = 2.0, max_ms = 5000 }

# Fibonacci sequence delays
[retry.backoff_strategy]
Fibonacci = { start_ms = 100, max_ms = 5000 }

`[quarantine]`

Controls test quarantine behavior.

Field	Type	Default	Description
`enabled`	bool	`true`	Enable quarantine functionality
`auto_quarantine`	bool	`false`	Automatically quarantine tests exceeding thresholds

`[quarantine.threshold]`

Thresholds for auto-quarantine. A test must be classified as flaky AND exceed at least one threshold.

Field	Type	Default	Description
`consecutive_failures`	u32	`3`	Consecutive trailing failures
`failure_rate`	f64	`0.20`	Overall failure rate
`flakiness_score`	f64	`0.15`	Bayesian P(flaky)

`[storage]`

Controls data persistence. Two backends are supported: SQLite (default) and PostgreSQL.

Field	Type	Default	Description
`backend`	enum	`"Sqlite"`	Storage backend: `Sqlite` or `Postgres`
`retention_days`	u32	`90`	Days to keep test run data; sessions left without any runs by the purge are removed with them

`[storage.sqlite]`

SQLite-specific settings. Only used when backend = "Sqlite".

Field	Type	Default	Description
`database_path`	path	`$XDG_DATA_HOME/ninety-nine/ninety-nine.db`	Path to the SQLite database file

[storage]
backend = "Sqlite"
retention_days = 90

[storage.sqlite]
database_path = ".ninety-nine/data.db"

`[storage.postgres]`

PostgreSQL-specific settings. Required when backend = "Postgres".

Field	Type	Default	Description
`connection_string`	string	–	PostgreSQL connection URL
`pool_size`	u32	–	Connection pool size

[storage]
backend = "Postgres"
retention_days = 90

[storage.postgres]
connection_string = "postgresql://user:password@localhost:5432/ninety_nine"
pool_size = 8

Warning: Setting backend = "Postgres" without providing [storage.postgres] will cause a startup error.

`[reporting]`

Controls output behavior.

`[reporting.console]`

Field	Type	Default	Description
`summary_only`	bool	`false`	Show only summary counts instead of full table

Full Example

[detection]
min_runs = 20
confidence_threshold = 0.99
window_size = 50
parallel_runs = 4

[detection.duration_regression]
enabled = true
min_history_runs = 10

[detection.duration_regression.threshold]
StdDev = 2.5

[retry]
unit_test_retries = 3
max_retry_time_secs = 120

[retry.backoff_strategy]
Exponential = { base_ms = 200, factor = 2.0, max_ms = 10000 }

[quarantine]
enabled = true
auto_quarantine = true

[quarantine.threshold]
consecutive_failures = 5
failure_rate = 0.15
flakiness_score = 0.10

[storage]
backend = "Sqlite"
retention_days = 60

[storage.sqlite]
database_path = ".ninety-nine/data.db"

[reporting.console]
summary_only = false

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