Skip to main content

311 posts tagged with "ai-agents"

View all tags

Personalization Belongs in a Dotfile, Not a Vector Store

· 12 min read
Tian Pan
Software Engineer

The first time a product team needs per-user agent behavior, somebody usually says "we should fine-tune" or "let's wire up persistent memory." A week later they have a vector database, a feedback-loop pipeline, and a roadmap item to monitor learned-state drift. They have built an ML system to solve a problem that, in nine cases out of ten, is a config file.

Look at what users are actually asking for: terser responses, bullets instead of prose, my company's name in the disclaimer, default to my preferred model, don't escalate to a human under $100, here is the project I am working on this week, never use emoji. None of that needs a model that has learned anything. It needs settings. The dotfile pattern — a versioned, declarative, per-user configuration repo — solved this for shells, editors, and CLIs forty years ago, and it is the right shape for AI agents in 2026.

Persona Overlays: When One Agent Needs Many Voices for Different Customer Cohorts

· 11 min read
Tian Pan
Software Engineer

A Fortune 500 procurement lead opens your support agent and asks why the SOC 2 report references a control your product no longer implements. Your agent answers in the same chipper voice it uses with hobbyists on the free tier — three exclamation points, an emoji, and a cheerful suggestion to "ping our team" with no escalation path or citation. The procurement lead forwards the screenshot to her CISO with one line: "This is who they sent to handle our compliance question." You lose the renewal not because the answer was wrong, but because the voice was wrong for the room.

Most teams ship one agent persona because the org chart has one support team. The customer base, however, is rarely that uniform. Enterprise buyers expect formality, citations, and named escalation paths. Self-serve users want quick answers and zero friction. Developers want code, not paragraphs. The single-persona agent reads as condescending to one cohort and unprofessional to another, and "let users pick a tone" punts a product decision to the user that the user shouldn't have to make.

The Pre-Launch Blast Radius Inventory: The Document Your Agent Team Forgot to Write

· 10 min read
Tian Pan
Software Engineer

The first hour of an agent incident is always the same. Someone notices the agent did something it shouldn't have — invoiced the wrong customer, deleted a calendar event for the CEO, posted a half-finished apology in a public Slack channel — and the response team starts asking questions nobody has written answers to. Which downstream system holds the audit log? Which on-call rotation owns that system? Was the call reversible, and within what window? Who owns the credential the agent used, and does that credential also let it touch other systems we haven't checked yet? The team that wrote the agent rarely owns those answers, because the answers live in the systems the agent calls, and nobody at launch wrote them down in one place.

That document is the blast radius inventory, and it is the artifact most agent teams discover the absence of during their first incident. It is not a security checklist, not a tool schema, not a runbook. It is an enumerated list of every external system the agent can touch and every fact you need on the worst day of that system's life. Teams that ship agents without one are betting that incident-response context can be reconstructed faster than the blast spreads, and that bet keeps losing as agents get more tools and the tools get more powerful.

The Abandon Primitive: Why Your Agent Loop Needs a First-Class Way to Quit a Plan

· 11 min read
Tian Pan
Software Engineer

Look at the loop primitives most agent frameworks ship: continue, return, retry, and a step budget that hard-stops the run. Notice what is missing. There is a path that says "the work succeeded," a path that says "the model wants to keep going," and a path that says "we ran out of money or patience and shot the loop in the head." There is no first-class path that says "the plan I am executing is wrong, and I want to throw it away and start a different one." The abandon primitive — an explicit, structured way for the planner to declare its current trajectory hopeless — is the missing verb in the agent loop's grammar, and its absence is responsible for a category of failures that are usually misdiagnosed as "the model needs more reasoning."

A planner three steps into a doomed branch keeps refining the same wrong plan because the loop's only exits are succeed, retry the last step, or hit the budget. None of those are "give up on the strategy and try a different one." So the agent does what the loop allows: it edits its plan in place, calls one more tool, asks for one more clarification, and burns through its step budget converging on a non-solution. When the wall finally hits, the user sees a polite failure message that is not an answer to their question. The cost of those wasted steps is real — production data suggests 5–10% of token spend on agent systems goes into retries that produce nothing usable, and that figure is dominated by long doomed branches, not isolated tool errors.

Your LLM Bill Is Half Your Agent's COGS — The Other Half Is The Part Nobody Is Monitoring

· 10 min read
Tian Pan
Software Engineer

The first time a finance team asks an AI product team to forecast unit economics, the conversation goes the same way. The team pulls up the inference dashboard, points at the monthly token spend, and says "that's our COGS." The CFO multiplies by projected volume, draws a line on a chart, and asks where the gross margin curve crosses 70%. Six weeks later, when the actual P&L lands, the inference number on the dashboard is correct and the gross margin is twenty points lower than the forecast. Nobody is lying. Inference was just half of what the agent actually costs.

The other half is distributed across line items that nobody on the AI team owns. The vector database bill grows quietly because retrieval volume tracks usage and re-indexing costs are billed against compute, not storage. The observability platform's invoice arrives from the platform team's budget. Embedding regeneration shows up as a CI cost. Telemetry storage is filed under data warehouse. Human review is in customer-success headcount. None of these line items is alarming on its own — and that is exactly why the integrated number is the one that surprises everyone.

Agents as Cron Jobs: When Scheduled Triggers Beat Conversational Loops

· 10 min read
Tian Pan
Software Engineer

Most "agents" in production today are background jobs wearing a chat interface. They do not need a user typing into them. They need a trigger, a state file, and a way to resume after the inevitable timeout. The conversational loop — request, tool call, request, tool call, indefinitely — is a demo affordance that quietly became the default execution model, and it is the wrong model for the majority of agentic work that ships.

The decision is not philosophical. It shows up on the bill, in the on-call pager, and in the percentage of runs that finish at all. A conversational loop holds a model session open across many turns, accumulates context, and dies if any link in the chain fails. A scheduled trigger fires at a deterministic boundary, runs to completion or to a checkpoint, and writes its state somewhere durable before exiting. One is a phone call. The other is a job queue. Treating the two as interchangeable is how a $200/month feature becomes a $40,000/month feature without anyone changing the prompt.

Agent Credential Blast Radius: The Principal Class Your IAM Model Never Enumerated

· 11 min read
Tian Pan
Software Engineer

The security org spent a decade killing off the "service account that can do everything." Scoped tokens, short-lived credentials, JIT access, per-action audit — the whole least-privilege playbook landed and stuck. Then the AI team wired up an agent, the prompt asked for a tool catalog, and the engineer requested the broadest OAuth scope the platform would issue. The deprecated pattern is back, wearing new clothes, and this time the principal calling the API is a stochastic loop nobody is sure how to scope.

The agent has read-write on the calendar, the file store, the CRM, and the deploy pipeline because the API surface couldn't be enumerated up front. The token is long-lived because no one wired the refresh path. The audit log records the bearer, not the action. And IAM owns human and service identity, the platform team owns workload identity, the AI team owns the agent's effective permissions, and the union of those three sets is owned by no one.

The Agent Permission Prompt Has a Habituation Curve, and Your Safety Story Lives on Its Slope

· 10 min read
Tian Pan
Software Engineer

There is a number that should be on every agent product's safety dashboard, and almost nobody tracks it: the per-user approval rate over time. Ship a permission prompt for "may I send this email" or "may I run this query against production," and the curve goes the same way every time. Day one, users hesitate, read, sometimes click no. By week two, the prompt is the fifth one this hour, the cost of saying no is doing the work yourself, and the click-through rate converges to something north of 95%. The team's safety story still claims that the user approved every action. The user, in any meaningful cognitive sense, did not.

This is not a UX problem that better copy can fix. It is the same habituation phenomenon that flattened cookie banners, browser SSL warnings, and Windows UAC dialogs, applied to a substrate that operates orders of magnitude faster than any of those. A consent gate is a security control with a half-life. Ship it without measuring how fast it decays, and you ship a checkbox the user is trained to ignore by week two — and a compliance narrative that depends on a click that no longer means anything.

The Human Attention Budget Is the Constraint Your HITL System Silently Overspends

· 10 min read
Tian Pan
Software Engineer

The 50th decision your reviewer makes this morning is not the same quality as the first. The architecture diagram does not show this. The capacity model does not show this. The dashboard tracking "approvals per hour" actively hides it. And yet the entire premise of your human-in-the-loop system — that a person catches what the model gets wrong — is silently degrading from the moment the queue begins to fill.

Most HITL designs treat reviewer time as an infinite, fungible resource. The team sets a confidence threshold, routes everything below it to a human queue, and declares the system "safe." Six weeks later, the approval rate has crept up to 96%, the queue is twice as deep as the staffing model assumed, and a sample audit shows that reviewers are clicking "approve" on edge cases they would have flagged on day one. The system has not failed. It has rubber-stamped its way into looking like it is working.

Pagination Is a Tool-Catalog Discipline: Why Agents Burn Context on List Returns

· 11 min read
Tian Pan
Software Engineer

Every well-designed HTTP API in your stack returns paginated results. Nobody loads a million rows into memory and hopes for the best. Yet the tools your agent calls return the entire list, and the agent dutifully reads it, because the function signature says list_orders() -> Order[] and the agent has no protocol for "give me the next page" the way a human user has scroll-and-load-more.

The agent burns tokens on rows it could have skipped. The long-tail customer with 50K records hits context-window failures the median customer never sees. The tool author cannot tell from the trace whether the agent needed all those rows or simply could not ask for fewer. And somewhere in your eval suite, the regression that would have flagged this never runs because every test fixture has fewer than 100 records.

Pagination is not a UI affordance. It is a load-shedding primitive — and the agent that consumes a tool without it is reimplementing every SELECT * FROM orders mistake the API designers in your company spent a decade learning to avoid.

Agent Memory Drift: Why Reconciliation Is the Loop You're Missing

· 11 min read
Tian Pan
Software Engineer

The most dangerous thing your long-running agent does is also the thing it does most confidently: answer from memory. The customer's address changed last Tuesday. The ticket the agent thinks is "open" was closed yesterday by a human. The product feature the agent has tidy explanatory notes about shipped in a different shape than the spec the agent read three weeks ago. None of this is hallucination in the textbook sense — the model is recalling exactly what it stored. The world simply moved while the agent was looking elsewhere.

Most teams treat memory like a write problem: what should the agent remember, how do we summarize, what's the embedding strategy, how do we keep the store from blowing up. That framing produces architectures that grow more confident as they grow more wrong. The harder problem — the one that determines whether your agent stays useful past week three — is reconciliation: the explicit, ongoing loop that compares what the agent thinks is true against what the underlying systems say is true right now.

Agent Traffic Is Not Human Traffic: Designing APIs for Two Species of Caller

· 11 min read
Tian Pan
Software Engineer

The API you shipped two years ago was designed for a single species of caller: a person, behind a browser or a mobile client, clicking once and waiting for a response. That assumption is now wrong on roughly half of every interesting endpoint. The other half of the traffic is agents — your own, your customers', third-party integrations using your endpoints as tools — and they have different physics. They burst. They retry forever. They parallelize. They parse error strings literally. They act on behalf of a human who will not be available to clarify intent when something breaks.

Most of the production weirdness landing in postmortems this year traces back to one architectural mistake: treating both species as the same caller class. Rate limits sized for human pacing get blown apart by an agent's parallel fanout. Error messages designed to be human-readable get parsed wrong by an agent that retries forever on a 400. Idempotency assumptions that humans satisfy by default get violated when an agent retries the same payload from a recovered checkpoint. Auth logs lose the ability to distinguish "the user did this" from "the user's agent did this on the user's behalf."

The fix is not a smarter WAF or a bigger rate-limit bucket. It is a deliberate API design that names two caller classes, treats their traffic as different shapes, and records the delegation chain so accountability survives the indirection.