Grasp · Comprehension Index Scan Report

Who still understands tokio-rs/tokio?

Computed from git metadata only; no source code contents were read.
touch-weighted · 3-year history window · last commit 60d ago · scores are comparable only against same-mode scans

Grasp Score

touch-weighted living knowledge across the repo

Active humans

23 / 388

contributors active in last 90 days vs. all-time

AI-attributed minimum

≥ 0.2%

hard evidence only. Just 4% of commits here carry any attribution signal, so the real share is higher

Inactive share

55.9%

work by authors with no commit in the window; silence, not proof of departure

Composition

64/26/8/2%

source / tests / docs / config share of scored work

Living, source only

47%

the headline recomputed over hand-written source alone

Score stability

volatile

90-day-cliff variant reads 0%–52% across 60/90/180-day activity windows; read the width before the middle value

Squash-merged history: 99% of the commits analysed here collapsed a whole pull request into one commit by one author. Squashing credits a single person for everyone's work and can strip the co-author trailers that name the rest (measured across heavy squashers, roughly a quarter to a third of squash commits still carry them, and those are credited), so for this repository the concentration figures are an upper bound, the bus factors are a lower bound, and the AI-attribution minimum is lower than it would be with the same work merged conventionally. That information is destroyed at merge time and cannot be recovered from the repository, so it is reported rather than corrected. Comparisons against a project that does not squash are comparisons across two different record-keeping systems.

Dark-code ranking

Modules ranked by comprehension risk: the unknown share, amplified by ongoing change and thin ownership. The green meter is living knowledge.

Module	Risk	Living knowledge	AI-attr.	Inactive	Bus	Heat/180d
tokio/src/sync	MED 55	41%	0%	66%	1	34
tokio/src/net	MED 53	42%	1%	66%	1	32
tokio/tests	MED 51	49%	0%	57%	1	130
tokio-util	MED 51	47%	0%	59%	1	44
tokio/src/runtime	MED 50	50%	0%	57%	1	172
tokio-stream	LOW 48	52%	0%	50%	1	51
tokio/src/io	LOW 47	47%	1%	57%	1	30
tokio/src/task	LOW 47	42%	0%	65%	1	9
tokio/src/time	LOW 46	42%	0%	65%	1	7
tokio/src/process	LOW 46	39%	0%	68%	1	1
benches	LOW 43	45%	0%	57%	1	6
.github	LOW 42	54%	0%	50%	1	35
tokio-macros	LOW 42	50%	0%	53%	1	18
tokio/src/macros	LOW 42	48%	0%	62%	1	10
(root)	LOW 41	55%	0%	47%	1	31
tokio/src	LOW 41	46%	0%	66%	1	4
examples	LOW 40	49%	0%	57%	1	8
tokio	LOW 40	60%	0%	37%	1	54
tokio/src/util	LOW 37	53%	0%	49%	1	10
tokio/src/fs	LOW 37	57%	0%	49%	1	22

One commit touched 81% of every file changed in this window. Wide, shallow commits, a formatter run or a license-header pass, add weight for their author across the whole surface while changing little. Worth looking at what that commit was before crediting the score to its author.

Public-repo caveat: "departed" includes drive-by contributors, overstating attrition relative to a company repo with a real roster. Engagement is a proxy for comprehension. Treat it as a potential indicator rather than a diagnosis.