Task Duration Estimates

Table of Contents

1. Overview
2. Running Task ETA
   1. Display states
3. Pre-run Hover Tooltip
   1. Tooltip format
4. Statistics Tab: Typical Duration
5. How It Works
   1. Exponential Moving Average (EMA)
   2. Variability (Coefficient of Variation)
   3. Known Limitations
6. Requirements

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Added in v1.8.0

Overview

Task Duration Estimates surface how long a task is expected to take using an Exponential Moving Average (EMA) computed from its recent execution history. No new data is collected — all estimates derive from the recentDurations ring buffer already stored by Task History.

Estimates appear in three complementary places:

Surface	When shown	What you see
Running task tree item	While a task is executing	~Xs remaining or Longer than expected (~Xs est.) replaces the file-path description
Pre-run hover tooltip	Before a task is started (idle)	Estimated duration: ~Xs (based on N runs, variability: Low/Moderate/High)
Statistics tab	Any time (requires ≥ 3 runs)	A dedicated Typical Duration row in each task’s metrics card

A minimum of 3 completed runs is required before any estimate is shown. Tasks with fewer runs display no ETA information.

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Running Task ETA

While a task is executing, its description in the task tree updates every second to show the time remaining based on the EMA estimate at the moment the task started.

Display states

Condition	Tree item description
Time remaining > 0	~Xs remaining
Task has exceeded the estimate	Longer than expected (~Xs est.)
Fewer than 3 historical runs	(unchanged — shows the file path as normal)

The ETA is computed once when the task starts and is not recalculated mid-run, so subsequent history updates do not alter the live display.

When the task finishes, the description reverts automatically to the original file-path text on the next render cycle. The task tree item itself is never mutated — the ETA is applied as a read-only projection, so stale text can never persist.

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Pre-run Hover Tooltip

Hovering over an idle task that has at least 3 completed runs shows a tooltip with the EMA estimate and a variability indicator.

Tooltip format

Estimated duration: ~45s (based on 12 runs, variability: Low)

The variability label describes how consistent the task’s run times are:

Label	Meaning
Low	Task finishes within ~15% of its typical duration — very predictable
Moderate	Run time varies by up to ~40% — reasonably consistent
High	Run time is highly variable — ETA is less reliable

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Statistics Tab: Typical Duration

The Statistics tab in the Task History panel includes a Typical Duration row in every per-task metrics card. This row shows the EMA alongside the variability bucket, making it easy to compare estimated vs. average duration.

When fewer than 3 runs have been recorded the cell displays —.

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How It Works

Exponential Moving Average (EMA)

The estimate is computed from the task’s recentDurations ring buffer (last 100 runs by default, configurable via workspaceTasks.metrics.maxDurationSamples).

\[\text{EMA}_t = 0.3 \cdot x_t + 0.7 \cdot \text{EMA}_{t-1}\]

• Seeded from the oldest sample: $\text{EMA}_0 = x_0$
• Iterates oldest → newest so recent runs carry more weight (α = 0.3)
• Returns the EMA in milliseconds; undefined when fewer than 3 samples exist

Variability (Coefficient of Variation)

\[\text{CV} = \frac{\sigma}{\mu}\]

CV range	Label
< 0.15	Low
0.15 – 0.40	Moderate
≥ 0.40	High

Known Limitations

• recentDurations includes both successful and failed runs. Short-lived failures can pull the EMA down. The variability label provides a visible signal when this is the case.
• The metrics key used for the pre-run tooltip is constructed from taskType, label, and workspace folder name. For tasks launched via Quick Open or with non-standard sources the key may not match, in which case no tooltip is shown.

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Requirements

• Minimum 3 completed runs — estimates are suppressed entirely for tasks with fewer than 3 entries in recentDurations
• Metrics must be enabled — set workspaceTasks.metrics.scope to workspace, global, or both (default: workspace)

See Metrics Configuration for storage and retention settings.