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311 posts tagged with "ai-agents"

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The Agent Undo Button Is a Saga, Not a Stack

· 10 min read
Tian Pan
Software Engineer

A user clicks "undo" on an agent action that fanned out to twelve tool calls. The agent sent two emails, created a calendar invite, updated a CRM record, charged a card, and posted to a Slack channel. Three of those operations are non-reversible by API. Two are reversible only by an inverse operation that fires its own downstream notification. The remaining seven each have their own definition of idempotency that the planner never reconciled. The undo button you shipped looks reassuring. It quietly succeeds about 60% of the time and silently fails the rest.

This is not a UX bug. It is a saga-pattern problem that distributed-systems engineers have been working on for thirty years, and ignoring that lineage is the most expensive way to discover it.

The Carbon Math of Agent Workflows: A Token Budget Is Now an ESG Disclosure

· 10 min read
Tian Pan
Software Engineer

A stateless chat completion sips electricity. A median Gemini text prompt clocks in at about 0.24 Wh; a short GPT-4o query is around 0.3–0.4 Wh. These numbers are small enough that nobody puts them on a board deck.

An agent task is not a chat completion. A typical "go research this customer and draft a reply" workflow can fan out to 30+ tool calls, 10–15 model invocations, and a context window that grows with every step. The energy cost compounds with the call graph. By the time the agent returns, you have not consumed one unit of inference — you have consumed fifty to two hundred. Suddenly the per-task footprint is in the same order of magnitude as a video stream.

That arithmetic is about to matter outside the engineering org. The EU's CSRD makes Scope 3 emissions disclosure mandatory for in-scope companies, with machine-readable iXBRL reporting required from 2026. The SEC dropped Scope 3 from its final rule, but any multinational with EU operations still has to answer the question. Procurement teams have started adding "what is the carbon footprint per user task of your AI feature?" to vendor questionnaires. Most engineering teams cannot answer it, because nobody instrumented it.

The Chargeback Ledger for Compound AI Systems

· 10 min read
Tian Pan
Software Engineer

The first time the CFO asks "what does the assistant cost us per month," the engineering team produces a number. The second time, a different team produces a different number. The third time, finance produces a third number, and somebody opens a spreadsheet that re-derives the bill from spans because nobody trusts any of the previous answers. This is the moment a compound AI system stops being an architecture problem and becomes an accounting problem.

The shape of the failure is structural. A single user request to "summarize my last quarter's customer feedback" triggers an agent owned by team A, which calls a retrieval tool maintained by team B, which calls a model hosted by provider X, which streams results back through a re-ranking tool from team C, which calls a different model from provider Y. One click; five owners; two invoices that arrive a month apart. Standard FinOps primitives — cost centers, allocation tags, account-level rollups — were designed to slice infrastructure that already had stable owners. They do not compose cleanly across an internal call graph that crosses team boundaries on every request.

The 2026 State of FinOps report puts 98% of FinOps teams on the hook for AI spend, and the same survey lists real-time visibility into AI costs as the top tooling gap. That gap is not "we cannot see the bill." The gap is "we cannot see who caused what slice of the bill, fast enough that anyone changes their behavior before the bill arrives."

Your Agent Has Two Release Pipelines, Not One

· 10 min read
Tian Pan
Software Engineer

A team I worked with shipped a "small prompt tweak" on a Wednesday afternoon. The same PR also added one new tool to the agent's registry — a convenience wrapper around an internal admin API that the prompt would now occasionally invoke. The eval suite passed. The canary looked clean. By Thursday morning a customer's billing record had been mutated by an agent acting on a prompt-injected support ticket, the audit trail showed the admin tool firing exactly as designed, and the on-call engineer's first instinct — roll back the prompt — did nothing useful, because the credential had already been used and the row had already been written.

The post-mortem framed it as a security review failure. It wasn't. It was a release-pipeline failure. The team had shipped two completely different asset classes — a behavioral nudge to the model and a new authority granted to the agent — through the same review, the same gate, and the same rollback story, as if they were the same kind of change. They aren't. And once you see them as two pipelines, most "agent governance" debates become much less mysterious.

The Ghost Employee in Your Audit Log: Agents With Borrowed Credentials Break IAM

· 10 min read
Tian Pan
Software Engineer

Pull up your SSO logs from this morning. Every Slack message, every GitHub PR, every calendar invite, every CI run, every Jira comment your AI agent produced — they all show the same thing the human-typed events show: a person's name, a session token, a green "successful authentication" line. Forensically, you have no way to tell which actions came from a human and which came from an agent the human launched and walked away from. That is the ghost employee problem, and almost every team that shipped agents in the last twelve months has it.

The shortcut that creates the problem is structural, not negligent. When you wire an agent into a tool, the easiest credential is the one already in the engineer's environment — their personal access token, their OAuth session, their device-bound SSO cookie. The alternative is a platform project: provision a first-class identity, federate it across every downstream service, wire it into the audit pipeline, build per-instance revocation. None of that ships in a sprint, and none of it shows up on a feature roadmap. So the agent borrows.

When Your CLI Speaks English: Least Authority for Promptable Infrastructure

· 13 min read
Tian Pan
Software Engineer

A platform team I talked to this quarter shipped a Slack bot that wrapped kubectl and accepted English. An engineer typed "clean up the unused branches in staging." The bot helpfully deleted twelve namespaces — including one whose name matched the substring "branch" but which happened to host a long-lived integration environment that the mobile team had been using for a week. No exception was thrown. Every individual call the bot made was a permission the bot legitimately held. The post-mortem could not point to a broken access rule, because no rule was broken. The bot did exactly what its IAM policy said it could do.

The Unix philosophy was a containment strategy hiding inside an aesthetic preference. Small tools with narrow surfaces meant that the blast radius of any single command was bounded by the verbs and flags it accepted. rm -rf was dangerous because everyone agreed it was; kubectl delete namespace required the operator to type out the namespace, and the typing was the gate. The principle of least authority was easy to enforce because authority was lexical: the shape of the command told you the shape of the action.

Then the wrappers started accepting English. Now "the shape of the command" is whatever the LLM decided it meant.

Reviewing Agent PRs Is a Different Job, Not a Faster One

· 10 min read
Tian Pan
Software Engineer

A senior engineer pulls up an agent-authored PR. The diff is clean. The tests pass. The naming is consistent. They skim it, leave a thumbs-up, and merge. Two months later, a different senior engineer is rewriting that module because the abstraction it introduced quietly leaks state across three call sites and the test suite never noticed because it asserted what the code does, not what the spec required.

This pattern is the dominant failure mode of code review in 2026. The reviewer instincts that worked on human-authored PRs — probe the author's intent, look for the bug they didn't think of, check whether the test reflects the design — break down on agent PRs because the bugs cluster in different places and the artifacts the reviewer sees are no longer the artifacts that matter.

The data backs the intuition. CodeRabbit's December 2025 analysis of 470 GitHub PRs found that AI-co-authored code produces about 1.7× more issues than human-authored code, with logic and correctness errors at 1.75×, security findings at 1.57×, and algorithmic and business-logic errors at 2.25× the human rate. Critical issues climb 1.4× and major issues 1.7×. The diffs read fluent, and that fluency is precisely the problem.

Shadow MCP: The Tool Servers Your Security Team Has Never Heard Of Are Already Running on Your Engineers' Laptops

· 13 min read
Tian Pan
Software Engineer

Your security team has a complete inventory of every SaaS subscription on the corporate card, every OAuth app with admin consent, every device on the corporate Wi-Fi. They have zero visibility into the seven processes bound to 127.0.0.1 on your senior engineer's laptop right now — a "deploy assistant" with a long-lived staging API token, a "ticket triager" subscribed to a customer-data Slack channel, a "release notes generator" with read access to the production analytics warehouse. None of it is on a vendor list. None of it shows up in the SSO logs. All of it is running on credentials the engineer already had, doing things nobody approved them to do.

This is shadow MCP, and it is the fastest-growing unmanaged authorization surface in the enterprise. The Model Context Protocol made it trivially cheap to wire any tool into any LLM, and engineers — being engineers — wired the obvious things first. Saviynt's CISO AI Risk Report puts the number at 75% of CISOs who have already discovered unsanctioned AI tools running in their production environments. The GitHub MCP server crossed two million weekly installs in early 2026. The Postgres MCP server, which gives an LLM a SQL prompt against any database the developer can reach, is north of 800,000 weekly installs. None of those numbers represent enterprise IT decisions.

The Expensive-to-Undo Tool Taxonomy: One Approval Gate Per Risk Class

· 9 min read
Tian Pan
Software Engineer

The "send email" tool and the "delete account" tool are sitting behind the same modal. Your user has clicked "Approve" forty times today, none of those clicks involved reading the diff, and the next click — the one that ships an irreversible mutation to a production database — will look identical to the forty before it. This is the failure mode of binary tool approval, and it is the default in almost every agent framework shipped today.

The framing problem is that "needs human approval" is treated as a single boolean attached to a tool, when it is actually a five-or-six-class taxonomy that depends on what kind of damage the tool can do and how recoverable the damage is. Teams that ship safe agents stop asking "does this tool need a confirm dialog" and start asking "what risk class does this tool belong to, and what gate corresponds to that class." The right number of approval gates is not one and not many. It is one per risk class, and you have to enumerate the classes before you can build the gates.

Your Tool Catalog Is a Power Law and You're Optimizing the Long Tail

· 11 min read
Tian Pan
Software Engineer

Pull a week of tool-call traces from any production agent and the shape is the same: three or four tools handle 90% of the calls, and a couple of dozen others split the remaining 10%. The catalog is a power law, but the framework treats it like a uniform list. Every tool description ships in every system prompt, every selection rubric weights tools equally, every eval samples the catalog as if a search-files call and a refund-issue call were drawn from the same distribution. They are not.

The cost of that flatness is invisible until it isn't. A team adds the eighteenth tool, the planner's accuracy on the original three drops two points, nobody can localize the regression to a specific change because everything moved at once, and the eval suite — itself uniform across the catalog — averages the slip into a number that still looks fine. Meanwhile the tokens spent describing tools the model will not call this turn now exceed the tokens spent on the user's actual prompt.

Tool-Composition Privilege Escalation: Your Security Review Cleared the Nodes, Not the Edges

· 10 min read
Tian Pan
Software Engineer

read_file is safe. send_email is safe. Your security review cleared each one against its own threat model: read-only access to a known directory, outbound mail through an authenticated relay with rate limits and recipient logging. Each passed. Both got registered. Then the agent composed them, and a single line of injected text in a customer support ticket turned the pair into an exfiltration tool that the original review had no language to describe.

The danger does not live in any node of the tool graph. It lives in the edges. Every per-tool security review you ran produced a verdict on a vertex; the actual permission surface of your agent is the set of paths through the catalog, and that set grows quadratically while your review process scales linearly. By the time your agent has fifteen registered tools, you have reviewed fifteen things and shipped roughly two hundred reachable two-step compositions, none of which any human auditioned.

The 95% Reliability Illusion: Why Your 10-Step Agent Fails 40% of the Time

· 12 min read
Tian Pan
Software Engineer

There is a moment in almost every agent project review that ends the conversation. Someone draws a small chart: end-to-end task success rate on the y-axis, number of tool-using steps on the x-axis. The line slopes down hard. The room goes quiet because everyone in it had been arguing about prompts, models, and retrieval strategies — and the chart is saying that none of those debates matter as much as the simple fact that the chain has too many links.

The math is one of the oldest results in reliability engineering, ported into a domain that pretends it is new. If every step in a pipeline succeeds independently with probability p, then n steps in series succeed with probability p to the n. Plug in numbers that sound healthy on a status report: 95% per-step reliability, ten steps, end-to-end success rate of 60%. Twenty steps gets you 36%. Thirty steps gets you 21%. The agent that "works 95% of the time" is the same agent that fails on a third of real user requests, because real user requests are not single steps.