Report

Weave AI Impact Report:
Q2 2026

Published August 2026 | Reporting period: April to June 2026
Router savings and codebase expertise extend into July.
System-measured benchmarks from 1,400+ engineering organizations. No surveys.

Executive summary

18 months into the agentic era, the question has flipped from "is AI making engineers faster?" to "where did the speed go?" This quarter's system data from 1,470 organizations and 21,409 engineers gives an unusually direct answer: in the median organization, output per engineer rose 1.8x in the three quarters from Q3 2025 to Q2 2026, and nearly every metric leaders use to steer that gain is now measuring the wrong thing.

0 20 40 60 80 100 0-10 engineers 11-20 engineers 21-50 engineers 51-100 engineers 101+ engineers Q3 25 Q4 25 Q1 26 Q2 26 W E A V E E N G I N E E R I N G I N D E X Output per engineer rose 1.8x in three quarters Median monthly output per engineer by team size, Q3 2025 to Q2 2026. Every bucket's median rose, from 2.0x in the smallest organizations to 1.5x in the largest. 22.9% of the cohort shipped less per engineer at the end of the window than at the start Source: Weave platform data, Q3 2025 - Q2 2026; constant cohort of 607 orgs active in all four quarters, each pinned to its Q2 2026 size bucket. weaveos.com

Scroll sideways or zoom to read the full chart.

Four themes define the quarter:

1. Value and volume have decoupled

Volume and value now move on separate curves. Since January 2025 merged PR volume is up 6x and the median merged PR grew from 36 lines to 109, while the value each PR carries rose 59%: three times the code for half again the value. The input side inflated further still, with tokens consumed per unit of shipped output up 14x since January. Platform-wide, AI's share of merged output value crossed the halfway mark in June at 52%, up from 41% in April. Every volume metric (lines, tokens, PRs, adoption) overstates progress; only complexity-weighted output survives as a ruler.

0k 100k 200k 300k 400k 459k 0.0x 0.5x 1.0x 1.5x 1.59x Jan 25 Apr 25 Jul 25 Oct 25 Jan 26 Apr 26 Jun 26 L E G A C Y M E T R I C I N D E X PR volume is up 6x, and each PR carries 59% more value Merged PRs per month across the platform, above, against output value per PR indexed to Jan 2025, below. Both panels are zero-based and share the x-axis. 9.8x more output value a month than Jan 2025, the two rates compounded Source: Weave platform data, Jan 2025 - Jun 2026. Output value per PR is indexed to Jan 2025 at 1.00x. weaveos.com

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2. The waste is not where you think

Of every $100 in AI session spend, only $26 ends in a clean ship: a session that completes its work and whose code merges. Another $29 merges without a completion signal, $20 completes and never merges, $17 carries no classified outcome, and $8 ends abandoned or blocked. Fewer than 4 in 10 agent sessions with a classified outcome complete. Of the tool calls that fail, the largest classified bucket at 41% is a file, path, or resource the agent expected and did not find, though an unclassified bucket of the same size sits beside it. The highest-leverage fix we can measure is boring: sessions that invoke a codified skill add 5.4x more lines.

W E A V E A I I M P A C T I N D E X · A G E N T S $20 of every $100 in session spend completes unmerged AI session spend allocated by what happened to the session and its code, Q2 2026. $26 of every $100 is unambiguously shipped, completed and merged $26 $29 $20 $17 $8 Code merged, $54 Code never merged, $46 PER $100 Shipped: completed and merged $26 Merged, no completion signal $29 Completed, never merged $20 No classified outcome $17 Abandoned or blocked $8 Source: Weave session telemetry joined to merged PRs, Q2 2026; 21,907 sessions, $458k. Segments rounded individually; may not sum to totals. weaveos.com

Scroll sideways or zoom to read the full chart.

1.8x
growth in output per engineer at the median organization over nine months, constant cohort; 22.9% of it shipped less
6x vs 59%
growth in merged PR volume against growth in the value each PR carries, since January 2025
$26
of every $100 of session spend ends in a completed session whose code merges

3. The quality panic is aimed at the wrong layer

The industry expected AI volume to break the quality gates. It hasn't: revert rate fell below 1% while monthly merged PR volume reached 432,000, and the median wait for review is at least 2.5x shorter than its 2025 peak. AI-signed review events grew 16x between Q4 2025 and Q2 2026, though they are still 1.1% of all reviews. The real structural risk is concentration: the top 10% of engineers produce roughly 40% of output at every organization size, and in 100+ engineer organizations 14% of the team holds half the codebase expertise.

4. Spend became governable, but most orgs haven't started

Routing is the AI cost lever that requires no behavior change from engineers. In July 2026, the most recent complete month, the Weave Router saved 58% against list price, and open-weight models generated 61% of those savings on 31% of routed traffic. Almost nobody is doing it yet: fewer than 1% of engineers on the platform routed a request in July, the Weave Router's second month of general availability. Read that as a starting line rather than a weakness. The lever is two months old, and routing is only now starting to look like a normal line item instead of an experiment. The spending gap between the top 1% of engineers by output ($34/day) and the bottom half ($2/day) is not where the waste sits; ungoverned defaults are.

The bottom line for leaders

The gain is real, and it is table stakes; your competitors got it too. What separates organizations now is conversion: measuring value instead of volume, aiming enablement at the bottom half of the distribution, engineering agent context instead of prompt phrasing, and routing every request like the purchasing decision it is. The rest of this report is the benchmark grid, segmented by organization size, so you can locate yourself against peers rather than averages.

<1%
revert rate in June 2026, on 432,000 merged PRs after bot and noise exclusions
58%
saved against list price by the Weave Router in July, the most recent complete month
61%
of those savings came from open-weight models, on 31% of routed traffic

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