The most valuable engineer isn't shipping features

Makers build new things. Menders tend what already exists, and most professional software work is mending. In this closing keynote from Rails World 2026, Robby Russell (Planet Argon) talks about the "local workshop" every mature Rails app builds on top of the framework: the patterns, shortcuts, workarounds and oral traditions that teams quietly learn to compensate for, and that AI coding agents now have to rediscover every time their context resets.

Drawing on client work, years of podcast interviews and conversations in conference hallways, Robby shares agrees that while producing code has gotten cheaper, deciding what belongs, what can be trusted and what should change still takes human judgment.

Transcript

1. The most valuable engineer isn't shipping features robby russell - planet argon
2. Four answers to the same question
3. Receive. Transform. Validate. Send.
4. ...software.
5. Nobody designed the confusion
8. How far do we go?
10. tt Which pa ern is best?
11. Assess their situation
12. Our verdict?
13. "We're doing it this way now." - nobody, 2019
14. Who were they to choose?
15. There was always another ticket...
16. And then you notice things
17. It all still works
18. "Huh?" - you
19. Nobody is alarmed
20. "Yeah, that's a little weird." - your future coworker
22. We learn where not to step HERE BE DRAGONS
23. ...and so we compensate
26. I am a... mender
27. Most software isn’t a blank canvas
28. We inherit more than we invent
29. Changing without breaking
30. The Lie
31. The Lie: This takes you away from the work.
32. The work around the work.
33. Reading the sediment
34. Field Notes
35. Field Correspondent
36. The work did not disappear
38. A common place to begin
39. You know where to look
40. You know where to look
41. The local workshop
42. Comparison creates judgment
43. What kind of weird is this?
44. What kind of weird is this? • Is this conventional Rails? • A deliberate adaptation? • An expired constraint? • An unfinished experiment? • Or an accident that’s become tradition?
45. Think of your app
46. "Yeah… That's a little weird." - you
47. The agent inherits the workshop
48. The advantage has limits
49. Shared leverage, local friction
50. The framework stops h ere
51. The repository is evidence
52. Equally plausible prior art
53. "Make CI Faster." - you, in codex
54. "Make CI Faster." • Better caching • Split a job • Remove unnecessary work • Save a minute
55. How far can it go?
56. fi The constraint is con dence
58. Make the change easier
59. Separate tidying from behavior
60. More changes. More queues. • The behavior changes • A cleanup PR • A doc update • Better tests • A dependency bump
61. "The genie produces code at a pace no human reviewer can match." - Kent Beck, December 2025
62. Output outruns evaluation
63. We've seen this before
64. The Mythical Agentic Man-Month?
65. Agents don't take feedback personally
66. A QUICK UX STUDY 🚿
69. The shower did not improve.
70. The friction we stop seeing • rm -rf tmp/cache for the fth time today • "Anybody deploying to staging right now?" • Restart the server... again. • Redis, then Sidekiq, then the server • The cron job that's actually a person with a calendar reminder • Seed data has never been useful • db:reset isn't useful • Forty scopes. Three of them identical • Don't double-click that bu on • The node_modules directory you delete monthly • bin/setup hasn't been used in years • The staging seed that's a prod dump from 2024 • The queue named default, doing everything • The class named after a company you stopped integrating with • data-turbo="false" on that one fi tt fi form • The jQuery that's still there for one datepicker • schema.rb or structure.sql, depending on who merged last • "Don't merge until I'm back" • Your shell alias nobody else has • STI that should have been two tables • The doc that is a Slack thread • Looking at your phone while the rst page renders after starting the server • # rubocop:disable, from a previous style guide • Not trusting staging because of one if Rails.env.production?
71. Humans learn to compensate
72. Agents keep rediscovering it
73. So what do we do?
74. Improving the workshop
75. Austin Story Senior Engineering Director Doximity
76. Brian Scanlan Senior Principal Engineer Fin (fka Intercom)
77. Many teams don’t have this
78. Who improves the workshop?
79. Who improves the workshop? • Who notices the friction? • Who fixes the onboarding scripts? • Who chooses the preferred pattern? • Who builds the generator? • Who turns the workaround into a tool?
80. Somebody has to...
85. The next mission should need less heroism
86. The gadget isn’t the outcome
87. A common hesitation
88. Sound familiar?
89. Reasonable questions
90. Reasonable stewardship
91. You do not need permission to do your job well. - Robby Russell, here... today...
92. Start smaller than you think • Name the friction • Find an accomplice • Improve one thing
95. What’s one drawer you could organize?
96. Curiosity needs structure.
97. A Framework
98. FAFO
99. Sometimes you just have to poke it.
100. WUTS
101. Wonder U T S
102. Wonder Unpack T S
103. Wonder Unpack Tinker S
104. Wonder Unpack Tinker Share
105. A curiosity framework.
107. Curiosity is a signal
108. WONDER Notice before you judge.
109. What made you pause?
110. What made you pause?
111. UNPACK Understand before you prescribe.
112. UNPACK • When was this introduced? • What problems was it solving? • What constraints shaped it? • Who depended on it then?
113. UNPACK 🚫⏭ fi Huh? "I know how to x this."
114. UNPACK • Trace one request end to end • Observe it happen in production • Measure how often it runs • Find the PR that introduced it • Ask someone who remembers why
115. Is there a statute of limitations on code decisions?
117. UNPACK Sometimes the weird thing is there for a good reason
118. TINKER Learn before you commit.
119. TINKER • Write down what you expect • Add one log line and wait • Turn one thing off • Compare two approaches • Put it behind a feature flag
120. TINKER The goal is information
121. SHARE Turn learning into leverage.
122. Sharing isn't... "Hey, I learned something weird today."
123. SHARE • Document the behavior • Explain the constraint • Name the canonical examples • Comment the why, not the what • Add it to bin/setup • Write the lint rule • Create the diagram • Improve the helper • Update the generator • Record the decision • Demonstrate the tool • Invite another engineer • Watch someone else use it • ...you get the idea
125. Wonder ✅ Unpack ✅ Tinker ✅ Share ⛔
126. Four answers to the same question ...all equally plausible prior art
127. order.save Background jobs Callbacks Inventory update Audit trails Notifications Broadcast Cache invalidation
128. order.save wonder unpack tinker • What actually happens when saving? share
129. order.save wonder unpack tinker share • What callbacks fire? • What jobs get enqueued? • What gets broadcast? • What notifications go out? • What gets written to the audit log? • What caches get invalidated? • What external systems get updated?
130. order.save wonder unpack tinker share • Disable one callback • Make one responsibility explicit • Measure
131. order.save wonder unpack tinker share
132. Let's try another one
134. app/middleware/utf8_sanitizer.rb wonder unpack • Is this still needed? tinker share
135. app/middleware/utf8_sanitizer.rb Huh? wonder unpack tinker share • Why is it here? • When was it added? • What were the circumstances at the time?
136. app/middleware/utf8_sanitizer.rb Huh? wonder unpack tinker share • Add logging • Track occurrences + Rails.logger.info("[utf8_sanitizer] scrubbed: #{env["HTTP_USER_AGENT"]}")
137. app/middleware/utf8_sanitizer.rb wonder unpack tinker share • Preserve the context “Still required by partner webhook traffic.”
138. Not everything old is wrong.
139. Observe where people compensate
140. Your development environment is a product
141. 🧑💻 👀
142. Familiar friction becomes invisible
144. YOUR
147. That gap is part of the workshop Our job isn't to choose a side. We need to shrink it. Today With work Large gap. More is documented. Less is guessed. Over time More shared understanding.
148. Where do devs struggle most when joining your Rails app? Ruby on Rails Community Survey 2026 ~1,800 responses
149. Where do devs struggle most when joining your Rails app? 1. DOMAIN MODEL + BUSINESS LOGIC (29%) 2. OLD OR INHERITED CODE (21%) Ruby on Rails Community Survey 2026 ~1,800 responses
150. Where do devs struggle most when joining your Rails app? 1. DOMAIN MODEL + BUSINESS LOGIC (29%) 2. OLD OR INHERITED CODE (21%) 3. LACK OF DOCUMENTATION (11%) Ruby on Rails Community Survey 2026 ~1,800 responses
152. Improving the Workshop Three kinds of investments
153. PRACTICE Make the path obvious 01
154. Make the path obvious Two paths... "Find the most recent one... and copy it."
155. Make the path obvious Two paths... "Find the most recent one..." ⚠ It was an experiment.
156. Make the path obvious Two paths... Team Judgment │ ▼ "Find the most recent one..." % bin/rails generate integration │ ▼ Integration Class Configuration Error Handling Tests Example Payload Documentation
157. The decision isn’t trapped in someone’s memory. It’s executable. Humans Agents Reviewers
158. Repository Instructions Canonical Example Generator / Template ↓ ↓ ↓ This is how we work here. This is the one we mean. Start here. . . . T N E M G D U J D SHARE ! E L B A T U C E X E E MAD
159. Don't make the agent guess
160. PRACTICE Make feedback worth believing fast trustworthy frequent 02
161. NOBODY WROTE THIS …but everyone learns it
162. NOBODY WROTE THIS …but everyone learns it
163. Agents use the same hidden manual
165. Make feedback proportional
166. In Another Life...
168. @clairetrashtours
169. PRACTICE Make mistakes reversible 03
170. fi "Let's nd out!" ?
171. When recovery is expensive…
173. Make mistakes cheaper to reverse 🟢 Feature Flags 🚀 Staged Rollouts ↩ Reversible Migrations 🔐 Limited Credentials 🧪 Safe Sandboxes 🌎 Disposable Preview Environments
174. Cheap recovery changes behavior Cheap Recovery Expensive Recovery ↓ ↓ More Experiments Fear ↓ ↓ More Learning Delay ↓ ↓ Better Systems 🤗 Stagnation 😕
175. Yesterday's choices become tomorrow's examples
176. Every example carries equal weight
177. Deletion is an architectural decision.
178. Some improvements barely look like work
179. Or explaining why it stays
180. Which one is "best"?
181. "We're doing it this way now." - you... next week?
182. You inherit all of it.
183. Notice what makes you pause
184. Somebody else will end up here, too
186. Improve the workshop. robby russell - planet argon