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David Crawshaw

David Crawshaw

@david-crawshaw · 19 positions · On ppll ↗

Software engineer; co-founder and former CTO of Tailscale, previously on the Go team at Google.

David Crawshaw did not write this page.

We collected these quotes from things they published elsewhere, and every quote links to where it was said. They have no account here and have not endorsed this site. Quotes are word for word; the short line under each one is our own restatement, not their wording. Their own site. Is this you? Claim it or ask us to remove it. Or tell us what is wrong here.

9 of David Crawshaw's claims fit 9 mental models. Most often: Activation energy, Cheaper means more, not less, Everything decays without maintenance.

Models they name

Their own words name the idea.

Activation energy

Starting is the hardest part, and the bigger the change, the more energy it takes to begin.

Used by 5 others

Most projects fail before they even begin because the activation energy required to start is too high.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale Most projects fail before they start. They fail because the activation energy is too high. jsonfile: a quick hack for tinkeringcrawshaw.io · 6 Feb 2024All korrents from this piece
    Most projects fail before they start. They fail because the activation energy is too high.

Incentives

Look at what people are rewarded for; it explains more behaviour than what they say, your own included.

Used by 89 others

A person directing an AI agent rather than writing code themselves has no incentive to actually read the resulting code or engage seriously with reviewer feedback.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale There is no incentive for the human driving the agent to actually read the code or spend time thinking about what the reviewer says. The agent principal-agent problemcrawshaw.io · 7 May 2026All korrents from this piece
    There is no incentive for the human driving the agent to actually read the code or spend time thinking about what the reviewer says.

S-curves and diminishing returns

Most growth slows as it matures; the question is whether the curve is flattening or something new is restocking it.

Used by 27 others

Local AI models will eventually catch up to frontier models once frontier progress hits diminishing returns.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale At some point frontier models will face diminishing returns, local models will catch up, and we will be done being beholden to frontier models. Eight more months of agentscrawshaw.io · 8 Feb 2026All korrents from this piece
    At some point frontier models will face diminishing returns, local models will catch up, and we will be done being beholden to frontier models.

Signalling

Much of what people do is a message about themselves, and a signal is believed only when it costs something to send.

Used by 16 others

Code review as a review mechanism depends on reviewers being able to infer effort from reading code, and AI-agent-generated code erases that signal.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale the reviewer is the principal, the contributor is the agent, and code review only worked because the reviewer could cheaply infer effort from reading the code. Agents collapse that signal. The agent principal-agent problemcrawshaw.io · 7 May 2026All korrents from this piece
    the reviewer is the principal, the contributor is the agent, and code review only worked because the reviewer could cheaply infer effort from reading the code. Agents collapse that signal.

Trade-offs

Every choice gives something up, so name the cost; and check, because some trade-offs everyone assumes are not real.

Used by 66 others

Programming is fundamentally the practice of making tradeoffs about what matters and what doesn't.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale Programming is the art of tradeoffs. You have to decide what matters and what does not. jsonfile: a quick hack for tinkeringcrawshaw.io · 6 Feb 2024All korrents from this piece
    Programming is the art of tradeoffs. You have to decide what matters and what does not.

Models we see in what they say

Our reading: their claim applies the idea without naming it. The claim is theirs; filing it here is ours.

Cheaper means more, not less

Make something cheaper to use and people use so much more of it that the total goes up (Jevons paradox).

Used by 16 others

Everything decays without maintenance

Institutions, code, cities and knowledge run down by default; keeping something alive is work that has to be paid for.

Used by 30 others

Most software has too few users or too short a lifespan for long-term maintenance costs to matter.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale Very few programs ever reach the point that they are heavily used and long-lived. Almost everything has few users, or is short-lived, or both. How I program with Agentscrawshaw.io · 8 Jun 2025All korrents from this piece
    Very few programs ever reach the point that they are heavily used and long-lived. Almost everything has few users, or is short-lived, or both.

Leaky abstractions

A shortcut that hides the details works until it doesn't; when it breaks, someone has to know what is underneath.

Used by 10 others

Cloud abstraction problems cannot be fixed by adding more abstraction layers on top.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale You cannot solve the fundamental problems with cloud abstractions by building new abstractions on top. I am building a cloudcrawshaw.io · 22 Apr 2026All korrents from this piece
    You cannot solve the fundamental problems with cloud abstractions by building new abstractions on top.

Skin in the game

Trust the judgment of people who pay for being wrong over people who only comment.

Used by 9 others

Making the person who directs an AI agent also own the deployment removes the principal-agent misalignment that agent-driven code review creates.

  1. David Crawshaw Software engineer; co-founder and former CTO of Tailscale there is no principal-agent problem, because the human driving the machine takes on the responsibility for its actions by owning the deployment. The agent principal-agent problemcrawshaw.io · 7 May 2026All korrents from this piece
    there is no principal-agent problem, because the human driving the machine takes on the responsibility for its actions by owning the deployment.