Timeline

Posts by month and year

Browse the archive chronologically, with counts grouped by year and month.

95 Total dated posts

2026

53 posts

May 2026

23 posts
  1. Agentic Systems Are Distributed Systems With an Unreliable Planner Agentic Systems A 33-part engineering series on distributed systems, agentic systems, harness engineering, and production harness agents.
  2. Ambiguous Outcomes Are the Core Distributed Systems Problem Agentic Systems The hard state in distributed systems is not failure, but not knowing whether the effect already happened.
  3. Idempotency Is Durable Intent Agentic Systems Idempotency works when it preserves a decision across retries, crashes, and uncertain outcomes.
  4. Reconciliation Is Where Correctness Becomes Real Agentic Systems A system is not correct because it accepted a command; it becomes correct when it can compare intent with reality and repair the gap.
  5. What I Wish More Engineers Understood About Power Life A clear-eyed model of power, trust, incentives, and responsibility in engineering organizations.
  6. Leases, Ownership, and Fencing Agentic Systems A lease only says who probably owns work right now; fencing is what stops stale owners from writing after they lose it.
  7. Backpressure Is a Product Boundary Agentic Systems Backpressure is where a system tells the truth about what it can accept, delay, prioritize, or refuse.
  8. Queues Are Not Reliability Agentic Systems A queue can preserve work and decouple timing, but it does not make processing correct by itself.
  9. Deadlines Beat Timeouts Agentic Systems Timeouts protect individual calls; deadlines protect the whole promise the system made.
  10. Replay Changes Everything Agentic Systems Replay turns production failures from arguments about logs into experiments against recorded inputs, decisions, and effects.
  11. Sagas Without Fantasy Rollbacks Agentic Systems A serious saga design treats compensation as forward recovery, not a pretend undo button.
  12. Control Plane vs Data Plane Failures Agentic Systems Separating control plane and data plane behavior keeps management failures from casually breaking committed work.
  13. Agents Are Unreliable Planners Attached to Real Tools Agentic Systems A production frame for treating agent plans as tentative while tool effects stay real.
  14. Tools Are Capabilities, Not Functions Agentic Systems A practical model for designing agent tools around authority, scope, and side effects.
  15. The Agent Action Lifecycle Agentic Systems A concrete lifecycle for turning uncertain agent intent into bounded, verified effects.
  16. Context Provenance Matters More Than Prompting Agentic Systems Why agent reliability depends on knowing where context came from, when it was captured, and what it is allowed to justify.
  17. Agent State Should Live Outside the Model Agentic Systems A practical argument for storing task state, approvals, actions, and verification outside the conversation window.
  18. Stop Conditions Are Safety Features Agentic Systems How explicit stop conditions keep agent systems from turning uncertainty into expanding side effects.
  19. Agents Need Read/Write Separation Agentic Systems Why useful agent autonomy starts by separating observation from mutation.
  20. Human Approval Is a Protocol Agentic Systems How to make human approval precise enough to govern agent actions instead of decorating them.
  21. Agent Observability Should Follow Decisions, Not Tokens Agentic Systems A decision-centered observability model for debugging agent behavior after real side effects.
  22. Why I Write Before I Decide Life How writing turns vague opinions into inspectable engineering decisions.
  23. The Model Should Not Be the Policy Engine Agentic Systems Why agent systems should keep policy enforcement outside the model even when the model helps interpret intent.

April 2026

16 posts
  1. A Harness Is a Controlled World Agentic Systems Agent harnesses earn trust by controlling the world around the model, not by asking the model to explain itself.
  2. Grade State, Not Speech Agentic Systems Agent quality should be judged by the state it leaves behind, because fluent explanations can hide unsafe actions.
  3. Replay Is the Difference Between Debugging and Guessing Agentic Systems Replay turns failed agent runs into inspectable infrastructure events instead of arguments about prompts.
  4. Test the Refusal Path Agentic Systems Safe agent systems need tested refusal paths, because declining action is a production behavior with side effects.
  5. Failure Injection for Agents Agentic Systems Agent harnesses should inject ordinary tool and state failures so teams can verify behavior before production does it for them.
  6. Regression Suites Should Be Built From Bad Runs Agentic Systems The most valuable agent regression cases come from real failures converted into replayable behavior contracts.
  7. Golden Behaviors Beat Golden Text Agentic Systems Agent tests should preserve required behavior instead of freezing exact prose that can pass while actions regress.
  8. Harnesses Must Catch Overreach Agentic Systems Agent harnesses need explicit overreach checks because the most dangerous failures often look like extra helpfulness.
  9. Watcher Agents Agentic Systems Watcher agents are read-only harness components that notice unsafe drift and propose interventions without taking ownership of the work.
  10. Adversary Agents Agentic Systems Adversary agents should create hostile fixtures and boundary tests, not become theatrical opponents in production workflows.
  11. Auditor Agents Agentic Systems Auditor agents review decision traces against policy and state, producing evidence-backed findings instead of vague confidence.
  12. Replay Agents Agentic Systems Replay agents reconstruct failed runs from durable traces so engineers can debug causes instead of arguing from summaries.
  13. The Career Value of Being Easy to Reason About Life Why reliability, clarity, and low-surprise behavior compound into senior leadership trust.
  14. Blast-Radius Agents Agentic Systems Blast-radius agents decompose risky agent work into reviewable units without deciding the organization's appetite for risk.
  15. Ambition Needs a Control Plane Life How to keep ambition useful by adding constraints, feedback, and explicit tradeoffs.
  16. Burnout Is a Throughput Bug Life A systems model for burnout that treats recovery as capacity planning, not weakness.

March 2026

5 posts
  1. Observability Pillars Engineering Notes from Parin's archive.
  2. The Personal Operating System of a Principal Engineer Life A practical operating model for attention, energy, writing, relationships, and technical leverage.
  3. How to Build Taste as an Engineer Life How engineers develop judgment by studying consequences, constraints, and user pain.
  4. The Case for Boring AI Infrastructure Engineering Why queues, caches, eval stores, audit logs, and boring controls beat magic in production AI.
  5. Latency, Tokens, and Trust in AI UX Engineering Why AI user experience depends on cost, waiting, uncertainty, and visible recovery paths.

February 2026

4 posts
  1. The Cost Model Every AI Product Needs Projects & Notes A unit-economics lens for token cost, latency, quality, and human review in AI products.
  2. Why Data Quality Problems Look Like Engineering Problems Engineering A taxonomy for separating data truth, pipeline behavior, model symptoms, and product expectations.
  3. Feedback Loops Beat Model Launches Engineering How feedback design determines whether AI systems improve, stagnate, or quietly drift.
  4. The ML Model Is Rarely the System Boundary Engineering A systems view of model behavior, data pipelines, fallbacks, product semantics, and human review.

January 2026

5 posts
  1. Evaluation Is the Product in AI Systems Engineering Why durable AI products are built around eval loops, not model launch announcements.
  2. AI Code Review Needs a Threat Model Engineering How to review machine-generated changes for subtle correctness, security, and maintainability risks.
  3. The Agent Loop I Trust for Production Code Projects & Notes A practical loop for using coding agents without outsourcing engineering judgment.
  4. Prompting Is Not the Hard Part of Agentic Development Engineering Why context design, verification, decomposition, and ownership matter more than clever prompts.
  5. Why AI Agents Need Smaller Interfaces Than Humans Engineering How narrow tools, explicit contracts, and small write scopes make agents safer and more useful.

2025

34 posts

December 2025

5 posts
  1. The New Skill Is Reviewing Machine Work Engineering A review rubric for AI-generated code that focuses on intent, contracts, failure modes, and tests.
  2. Agentic Coding Changes the Bottleneck, Not the Responsibility Engineering Why AI-assisted development moves senior responsibility toward framing, review, and integration.
  3. When Speed Becomes a Culture Smell Engineering The difference between healthy urgency and speed used to hide poor choices.
  4. DDD Engineering Notes from Parin's archive.
  5. The Founder-Friendly Engineer Is Not a Yes-Man Engineering How to support founder urgency while protecting the system from avoidable damage.

November 2025

5 posts
  1. Hiring for Ownership When the System Is Still Moving Engineering Signals for hiring engineers who can own ambiguous systems without needing stable ground.
  2. The First 90 Days After a Technical Pivot Engineering How to reset architecture, morale, and delivery after the product direction moves.
  3. Startup Engineering Is the Art of Choosing Which Fires Stay Lit Engineering A startup operating model for separating existential fires from noisy but survivable ones.
  4. Why Senior Engineers Should Read P&L Statements Projects & Notes How revenue, margin, cost, and risk make technical prioritization sharper.
  5. Promotion Packets Are Written One Decision at a Time Engineering How principal-level evidence accumulates through durable decisions, not last-minute brag documents.

October 2025

4 posts
  1. The Dangerous Comfort of Being the Smartest Person in the Room Life Why senior engineers must trade cleverness for systems that make other people sharper.
  2. How to Make Executives Trust Engineering Judgment Engineering A communication model for translating engineering risk into business choices without theater.
  3. Influence Is Built Before the Meeting Engineering Why senior influence comes from pre-wiring context, risks, and tradeoffs before rooms fill up.
  4. The Quiet Power of Writing the Decision Record Projects & Notes How lightweight decision records create memory, alignment, and better reversibility.

September 2025

4 posts
  1. The Architecture Review That Actually Works Engineering A review format that tests assumptions, failure modes, and operating ownership instead of style.
  2. How to Disagree With a Staff Engineer Without Making It Political Engineering A conflict model for keeping senior technical disagreement attached to evidence and risk.
  3. A Principal Engineer's Guide to Saying No Engineering How to refuse unsafe work while preserving momentum, trust, and options.
  4. Technical Debt Is Often Unpriced Strategy Debt Engineering A sharper way to discuss debt when the real issue is changing strategy, incentives, or ownership.

August 2025

5 posts
  1. Why Platform Teams Accidentally Become Gatekeepers Engineering How internal platforms drift from leverage engines into approval queues, and how to pull them back.
  2. The Best API Design Happens Before the API Exists Engineering A review method for designing APIs from lifecycle, failure, and ownership before endpoint shape.
  3. Backward Compatibility Is an Organizational Skill Engineering How compatibility survives when teams plan contracts, migrations, and deprecation paths together.
  4. Feature Flags Are Distributed Systems in Disguise Engineering The hidden consistency, cleanup, and ownership risks inside flag-driven delivery.
  5. The Difference Between Latency Budgets and Latency Wishes Engineering A practical model for converting performance goals into owned budgets across a request path.

July 2025

4 posts
  1. Observability Without Ownership Is Expensive Decoration Engineering Why dashboards only become useful when somebody owns the question they are supposed to answer.
  2. Incident Reviews Should Change Roadmaps, Not Just Runbooks Engineering How to make incident reviews produce prioritization changes instead of better-formatted regret.
  3. The Reliability Work Nobody Wants to Fund Engineering A framing for turning invisible reliability labor into risk reduction leaders can evaluate.
  4. Idempotency Is a Product Requirement Engineering Why safe retries depend on product semantics, user-visible effects, and organizational ownership.

June 2025

5 posts
  1. The Queue Is Not the Architecture Engineering How to reason about async workflows by ownership, ordering, failure semantics, and reconciliation.
  2. Unit economics Projects & Notes Business metrics for engineers who want their technical decisions to connect to the P&L.
  3. Good Distributed Systems Are Designed Around Boredom Engineering Why predictable recovery paths matter more than clever steady-state architecture.
  4. The Hidden Cost of Just One More Service Engineering A principal-engineer checklist for deciding when a service boundary is worth its operational tax.
  5. Why Most Migrations Fail Before Code Starts Engineering The migration risks that show up in ownership, sequencing, and rollback design long before implementation.

May 2025

2 posts
  1. Architecture Is Mostly Deciding What Must Not Change Engineering A practical way to separate durable constraints from implementation details before design hardens.
  2. The Principal Engineer's Real Job Is Reducing Ambiguity Engineering A field guide to turning vague technical anxiety into decisions, owners, and reversible next steps.

2024

8 posts