Anthropics — Engineering Performance
11 engineers now deliver what 57 would have in Q1 2025.
Performance snapshot
Today's rolling 90-day reading for Anthropics, compared with the start of the series. Pick a window to move that comparison point.
Avg. perf / dev / mo
+4410.9%
0.05 → 2.08 ETV
Active engineers
+450.0%
2.0 → 11.0
Features
+3.9pp
25.2% → 29.1%
vs. 500 OSS index
0.54x
0.05x → 0.54x · −46% below
Engineering capacity
Effective engineers behind Anthropics, against its pre-AI baseline. Each subject has its own: Anthropics's is 0.40 ETV / dev / mo, its first reading in Q1 2025. Per-engineer ETV divided by that gives a capacity multiple, and that multiple applied to the engineers active in the trailing 90 days turns it into engineer-equivalents. The line is the real headcount, so the gap between line and area is what the leverage is worth. Because each baseline is its own, every subject opens at 1.0x on its first day: multiples measure improvement and are not comparable between subjects.
Anthropics vs. 500 OSS Performance Index
Per-engineer ETV for Anthropics against the pooled 500 OSS Performance Index. Both lines are 90-day rolling averages scaled to a 30-day month, so they share one axis and can be read against each other at any point. Pick a window to zoom the chart to it. Latest reading: Anthropics is 46% below the index (2.08 vs 3.85 ETV/dev/mo). At the start of the tracked period the gap was 95% below.
Behind the numbers
Written summary of the work completed each month.
During August 2026, the team recorded 280 commits, delivering core enhancements across the buffa protocol buffer engine and tool execution runners across multiple SDKs. Delivery remained steady in line with the recent run rate, though the Fixes score rose to 16 (+104% vs 8-score 5-month average) while the Features score shifted to 19 (-42% vs 33-score 5-month average). Key improvements centered on memory bounds enforcement, shared descriptor pools, and multi-turn pause handling.
Highlights
- Optimized macOS sandbox profile generation in ee6b2eba (Dylan) by folding literal deny paths into alternation regexes, reducing profile size from 960 KB to 71 KB for 800 children.
- Introduced shared descriptor pool capabilities across `buffa-build` and code generator plugins in 03585645 (Harrison) and 41349983 (Harrison), eliminating per-package descriptor duplication.
- Optimized constant generation in `buffa-codegen` via c7169eb4 (Tim) by emitting single byte-string literals for
FILE_DESCRIPTOR_SET_BYTES, achieving up to 21x speedups and $O(1)$ token complexity. - Expanded marketplace integrations by onboarding plugins including
scandit-sdked404106 (abibbs-ant),hubspot-sales54055099 (tobin),gc-ai588a12db (tobin),unstructured-foundatione7dc7006 (tobin), anddynatrace4d2a5994 (tobin).
Observations
- BetaToolRunner required synchronized cross-SDK bug fixes to handle
pause_turnand compaction stop reasons across PHP 8f0533c6 (dtmeadows-ant), C# c1f6f630 (dtmeadows-ant), Ruby 06944d21 (dtmeadows-ant), Kotlin/Java 5ec58b82 (dtmeadows-ant), TypeScript 36e12854 (dtmeadows-ant), and Go 9c311c1f (dtmeadows-ant). - Memory budget enforcement was systematically extended across the buffa ecosystem to prevent unbounded memory growth, covering reflective dynamic decoding fed7e0ae (Iain), lazy view parsing 642ac657 (Iain), textproto parsing 9cb5fdd3 (Iain), and generated view decoding e3738fa1 (Iain).
- Compared to the 5-month average, Fixes score increased +104% (16 vs 8 5-month average) while Features score dropped 42% (19 vs 33 5-month average), reflecting an emphasis on protocol correctness and memory safety across 280 commits.
- `buffa-codegen` required multiple namespace isolation fixes, including qualifying
::serde::paths in ca173c28 (Minh) and::core::fmtpaths in 47d412a7 (Harshit) to prevent compiler shadowing issues.
Based on 280 commits37.1 ETVUpdated Sep 30, 2026, 4:01 PM
Repositories
Where each repository stands: average performance per engineer per month over the last 90 days, with the rolling 90-day curve behind it. The range picks the window (past 90d): it sets how much of the curve you see, the Δ across it, and the span the work mix is measured over. Ranked highest first.
buffa
Avg performance
6.01 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
knowledge-work-plugins
Avg performance
1.51 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
claude-agent-sdk-python
Avg performance
1.47 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
sandbox-runtime
Avg performance
0.69 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-php
Avg performance
0.67 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
claude-code-action
Avg performance
0.57 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
claude-plugins-community
Avg performance
0.04 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
claude-plugins-official
Avg performance
0.03 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
claude-code
Avg performance
0.01 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-python
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-typescript
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-csharp
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-go
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-ruby
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
anthropic-sdk-java
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
—
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
Performance Composition
Each month's output split by type of work: Features (new value), Maintenance (sustaining systems), Tests, Docs, and Fixes (rework). The yellow line is output per engineer, so when it rises each engineer is delivering more, whatever the team size did. Unit: Engineering Throughput Value (ETV).
Cost per Performance Unit
−98%
If performance per engineer more than doubled, each unit of engineering performance now costs approximately 98% less than at the baseline 90-day window (ending 2025-04-01). Treat this as a direction, not a price: the exact figure depends on fully-loaded engineer cost, but which way it moved is not in doubt.
Effective Capacity Added
+485 engineers
At today's productivity, the current 11-person team delivers the performance equivalent of 496 engineers at the baseline 90-day rolling window (ending 2025-04-01). That's roughly 485 engineers worth of capacity added through productivity gains, not hiring.
CapEx vs OpEx
Each month's work split two ways. CapEx (capitalizable investment) is the work that builds the asset: Features, plus the Tests that prove it works and the Docs that explain it. OpEx (operating expense) is keeping it running: Maintenance and Fixes. The yellow line is the CapEx share, so a rising line means more of the month went into building new rather than sustaining what exists. Unit: Engineering Throughput Value (ETV).
Hours per Repository
Trailing 90-day window (64 working days). Org-level capacity is allocated to each repo by its share of org performance, then split CapEx / OpEx by that repo's own Features + Tests + Docs vs Maintenance + Fixes mix.
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 0.0%
- OpEx %
- 100.0%
Feature Contribution
Who shipped each month's new feature work, as a share of that month's total. Bands of similar width mean new value is coming from across the team; one band that stays wide means most of it rests on the same person. Named engineers shipped the most Features over the period. Everyone else is grouped as Others.
Iain McGinniss
74 ETV · 56% share
Qing Wang
7 ETV · 5% share
Ashwin Bhat
7 ETV · 5% share
Bryan Thompson
6 ETV · 5% share
Tobin South
6 ETV · 4% share
Robert Craigie
5 ETV · 4% share
Quarterly Summary
Engineers and the Features / Maintenance / Tests / Docs / Fixes mix for each quarter. Cost / Perf Unit is what one unit of performance costs against Q2'25. Engineers vs headcount is measured against this org's own pre-AI baseline instead, its first reading in the index, so it agrees with the capacity tile and chart above.
- Engineers
- 7
- Cost / Perf Unit
- 0%
- Engineers vs headcount
- +1 engineer
- Work mix
- 36% Features
- Engineers
- 9
- Cost / Perf Unit
- −43%
- Engineers vs headcount
- +9 engineers
- Work mix
- 39% Features
- Engineers
- 12
- Cost / Perf Unit
- −27%
- Engineers vs headcount
- +6 engineers
- Work mix
- 43% Features
- Engineers
- 16
- Cost / Perf Unit
- −74%
- Engineers vs headcount
- +52 engineers
- Work mix
- 59% Features
- Engineers
- 18
- Cost / Perf Unit
- −80%
- Engineers vs headcount
- +81 engineers
- Work mix
- 37% Features