Call `d2 --layout=tala` and the engine does not settle on an arrangement directly. It runs a search that uses randomness, evaluates three seeds by default, and keeps the highest-scoring result [8]. Scoring criteria include symmetry, median distance and flow [6]. Two candidate layouts are therefore computed and thrown away on every render [1].
Determinism holds, under one narrow condition. Fixed input with fixed seeds produces the same output [9]. Input is exactly the thing that does not stay fixed when diagrams live in text. Add a single node and much of the diagram can reorganize [10]. Dagre and ELK tend to hold more of the previous layout through a small edit [11].
Where that lands depends on what you commit. If only the `.d2` file is in git and SVGs are generated at build time, a reshuffle costs you nothing. If the rendered file is checked in, adding one service box can rewrite most of it, and whoever approves the pull request has to read a new picture to verify a one-line change. Long, directional graphs are a separate matter: Wang said he often prefers Dagre or ELK for those, and TALA runtime can grow nonlinearly as diagrams get larger [12].
The v0.9.0 release notes report SVG rendering approximately 10 times faster across the project's end-to-end corpus [15]. Read the harness before you plan around the number. D2's benchmark repository times the complete command-line process, including rendering and writing the output file, rather than layout time alone [13]. The repository also states that its results came from one desktop session with uncontrolled background activity, and should be treated as reproducible project benchmarks rather than a controlled independent performance study [14]. For that figure to transfer, your corpus has to resemble the project's and your bottleneck has to be rendering rather than layout. It says nothing about TALA's layout cost, which is the part that scales badly.
Credit where the engineering is honest: the announcement documents the seed randomness, the edit instability, the weak fit for directional graphs and the nonlinear runtime [8][10][12]. That section does not usually survive contact with a pricing page. It is also the kind of disclosure that only becomes cheap to make once the engine stops being a product, which is the trade the week actually contains.
The source now sits inside the D2 repository beside the Dagre and ELK implementations instead of in the archived proprietary TALA repository [3], and selection is a flag: `--layout=tala` [2]. Proprietary TALA and the paid D2 Studio editor were what funded D2's development, according to Wang's September 7 announcement [5]. That line is closed [4]. So the escalation path for a bad TALA score is now a patch against the D2 repository, merged on the schedule of a maintainer who has said his time commitment is limited [16].
