-rw-r--r-- 10m Agent runtime An unknown outcome is its own state
A process crashes mid-execution. The audit log shows the action was authorized. The runtime logs show it was attempted.
Writing
root@amaltsev >:~/writing$ ls -la
69 notes on agent runtime security, embedded Rust, and the parts of a system that break in production.
Subjects
mode posts name subject
drwxr-xr-x 24 Agent runtime/ The argument that an agent is two systems joined by a seam, and that the seam needs its own authority, budget and evidence.
drwxr-xr-x 26 Embedded/ Twenty-six posts on embedded Rust: firmware, peripherals, and the edge inference built on top of them.
drwxr-xr-x 9 Systems/ What is under the application: the compiler, the memory model, the web server, the toolchain.
drwxr-xr-x 8 Making/ The things built because they were interesting: a shooter, a Solana program, a cross-stitch generator, a pomodoro timer.
drwxr-xr-x 2 Silicon/ Two long reads on what the hardware is actually made of, written around the firmware series for the same reason.
Subject
Tags
All writing
mode date min topic name
-rw-r--r-- 10m Agent runtime Four valid permissions and one chain nobody approved
Every step is in scope. The chain is a bulk data export to an external recipient. The agent executes them in order, because the task it was given was "produce a customer report".
-rw-r--r-- 13m Agent runtime Testing agent security policies against adversarial inputs
A policy has a test suite. The tests pass. Then someone finds an input that gets through, and the retrospective is always the same shape.
-rw-r--r-- 7m Agent runtime How to build an audit trail for AI agent tool calls that survives an auditor
Most agent audit logs are a table someone can UPDATE. That records what the system believed at write time.
-rw-r--r-- 10m Agent runtime Operator control lives in state the agent cannot reach
The worker is on another pod. The queue keeps delivering jobs. Another worker picks up the in-flight execution.
-rw-r--r-- 9m Agent runtime Agents cannot widen their own authority
There is a question most governance frameworks never ask, because it does not come up until an agent can write code, configure integrations or modify its own workflows.
-rw-r--r-- 9m Agent runtime Authority is durable, and evidence expires on its own clock
An agent is authorized to issue refunds up to five hundred dollars. The permission is valid, and the agent uses it correctly.
-rw-r--r-- 11m Agent runtime A tool name is a label: MCP authorization binds to identity
The trust list has an entry that says delete_user is allowed. What the agent calls is delete_user. Same string, two different things.
-rw-r--r-- 10m Agent runtime Scope an agent's permissions to the credential it holds
Three agents, one platform. The support agent reads the CRM, opens tickets, and refunds up to fifty dollars.
-rw-r--r-- 12m Agent runtime Reducing approval fatigue without removing the control
A team wants an agent that issues refunds. Security is nervous. There are exactly two options on the table, and both are bad.
-rw-r--r-- 15m Agent runtime Which fields are material? What makes a digest mean something
A tool is described by a JSON schema: its parameters, their types, what it accepts. This vocabulary fits an interface.
-rw-r--r-- 8m Agent runtime An approval is durable security state
The sequence is short. An agent submits an action for approval. The operator approves it. The agent crashes.
-rw-r--r-- 10m Agent runtime Binding a human approval to the exact payload it authorized
Every framework ships a human-in-the-loop step. A human sees a card, the human clicks approve, the tool runs.
-rw-r--r-- 11m Agent runtime How human-in-the-loop approvals get bypassed on agents
A team ships a human-in-the-loop approval step. The tests pass, the demo works, the security review signs off.
-rw-r--r-- 11m Agent runtime Six enforcement paths, six declared defaults
Fail-closed is a one-sentence rule: when the rule cannot be evaluated, refuse. Every enforcement system claims it.
-rw-r--r-- 10m Agent runtime The iteration cap lives inside the agent, and that is the problem
A tool starts returning poor results. The agent notices, retries, gets poor results again, retries. Four hundred calls later it either trips a provider rate limit or exhausts the budget.
-rw-r--r-- 6m Agent runtime Atomic budget reservation in Redis Lua: pattern and failure modes
Between the get and the decrby, every other agent in the system reads the same stale balance and draws the same conclusion.
-rw-r--r-- 7m Agent runtime How to enforce a hard budget on every LLM call your agent makes
Every "control your LLM spend" guide reaches the same place: you set a monthly cap somewhere and hope the number on the dashboard means something.
-rw-r--r-- 8m Agent runtime An agent budget is an authorization decision
The first version of this always looks the same. There is a number, the number grows, and when the number crosses a threshold the request is rejected.
-rw-r--r-- 13m Agent runtime Agent security layers: what each category can and cannot catch
Almost every comparison of agent security tools lines up vendors on a feature grid and lets the reader decide.
-rw-r--r-- 10m Agent runtime Every authorization is an instance of a permission category
Same agent. Same tool. Same permission. A support agent with refund access approves a twenty-dollar refund, which is exactly what it is there for.
-rw-r--r-- 9m Agent runtime Intercepting tool calls without patching framework internals
The request that shows up repeatedly in agent framework issue trackers is a developer who wants to inspect and block a tool call before it executes.
-rw-r--r-- 8m Agent runtime Treat an agent as two systems joined by a seam
An agent produces a perfectly acceptable response and then sends the wrong payment, deletes the wrong resource, modifies the wrong record, or calls a tool with a mutated argument.
-rw-r--r-- 8m Agent runtime The AI pipeline is not optional
Most production AI systems have an excellent model and a mess around it. I have seen GPT-4, Claude and Gemini sitting behind hardcoded prompts, zero validation and no separation of concerns.
-rw-r--r-- 4m Embedded From device to system: communication, backend, and dashboard for an embedded AI product
This final article connects the embedded AI device to the real world. It describes how inference results leave the MCU, travel through MQTT and HTTP, land in a Rust backend.
-rw-r--r-- 4m Embedded TinyML on MCU: from dataset to real-time inference in Rust firmware
The TinyML lifecycle on a microcontroller, from dataset preparation and model training to TensorFlow Lite Micro on bare metal, with the model bound into Rust firmware through a custom FFI wrapper.
-rw-r--r-- 10m Embedded Hardware and firmware organization: the foundation of an AI device on the ESP32-S3
This article covers the hardware I use in my AI device project, why I chose it, and how I structured the firmware in Rust.
-rw-r--r-- 2m Embedded Why overspecialization is over, and how I decided to create my own AI device on MCU
This series covers the building of an ESP32-S3 device with ML built right into the firmware, along with the decisions, compromises, and challenges that came up along the way.
-rw-r--r-- 2m Making From image to pattern: building a cross-stitch generator as a CLI tool
This project converts raster images into cross-stitch and needlepoint patterns. The output is a structured, printable and editable SVG pattern, with full control over the size and the color palette.
-rw-r--r-- 1m Embedded nrf52833 BBC micro:bit note
A playground for the micro:bit v2.21: GPIO, I2C, SPI, UART, ADC and PWM experiments on the nrf52833.
-rw-r--r-- 2m Embedded MCU Synchronization
Synchronization is what keeps the processor, the peripherals, the timers and the interrupts operating in a consistent and accurate manner, based on a common clock source.
-rw-r--r-- 4m Embedded Interrupts (ISR, IVT, NVIC)
An interrupt lets the microcontroller respond to an important event without spending cycles polling its peripherals.
-rw-r--r-- 2m Embedded MCU Clock System
The clock system is the basis for timers and interrupts. It sets the pace of every digital component of the microcontroller.
-rw-r--r-- 3m Embedded Timers
Timers are hardware modules of the microcontroller for actions with time counting and event generation without the participation of the main code.
-rw-r--r-- 3m Embedded PWM (Pulse Width Modulation)
The classic way to do that is to reduce the voltage through a rheostat or a potentiometer. That is inefficient, since part of the energy is lost as heat.
-rw-r--r-- 2m Embedded Basic Embedded Rust Flow (Cortex-M)
A step-by-step template for a Cortex-M Rust project: config.toml, rust-toolchain.toml, memory.x, probe-rs, defmt and the panic handler.
-rw-r--r-- 3m Embedded MCU Peripherals
Microcontroller peripherals are functional blocks integrated into the chip that enable it to interact with the outside world or carry out specific tasks, often without involving the processor core.
-rw-r--r-- 3m Embedded MCU Registers
A processor register is a quickly accessible location available to a computer's processor.
-rw-r--r-- 3m Embedded CPU and Peripheral I/O Communication: Approaches and Trade-offs
A microcontroller talks to its peripherals through one of a small number of I/O models, and the choice decides how much of the CPU's time the transfer costs, how quickly the peripheral gets serviced.
-rw-r--r-- 3m Embedded MMIO (Memory-Mapped I/O)
MMIO (Memory-Mapped I/O) is a way for the central processing unit (CPU) to interact with peripheral hardware devices.
-rw-r--r-- 6m Embedded Debugging firmware
Software development runs in a cycle: write, run, check, fix. On a desktop, debugging is simplified by built-in logs, breakpoints and step-by-step code execution directly in the IDE.
-rw-r--r-- 5m Embedded I2C (Inter-Integrated Circuit)
I2C (Inter-Integrated Circuit) is a low-speed two-wire master-slave serial protocol, widely used for short-distance data transmission over a data bus (SDA) with a clock synchronization line (SCL).
-rw-r--r-- 4m Embedded SPI (Serial Peripheral Interface)
SPI (Serial Peripheral Interface) is a low-speed four-wire master-slave full-duplex serial protocol, widely used as a faster alternative to UART/I2C for transferring data between an intelligent…
-rw-r--r-- 2m Embedded UART (Universal Asynchronous Receiver / Transmitter)
UART (Universal Asynchronous Receiver / Transmitter) is a low-speed two-wire asynchronous multi-duplex serial protocol.
-rw-r--r-- 2m Embedded Serial Protocols
Digital systems are built on bits, and beyond using bits they often have to move them between two components, an MCU and a sensor or an LCD, for instance.
-rw-r--r-- 6m Embedded Embedded crates ecosystem
In general, developing programs for an MCU is aimed at obtaining some information from the surrounding world, performing necessary calculations with this data and interacting back.
-rw-r--r-- 2m Embedded RP2040 Pico W Lab note
A playground for the Raspberry Pi Pico W: Wi-Fi, GPIO, I2C, SPI, UART, ADC and PWM experiments on the RP2040.
-rw-r--r-- 19m Embedded Building Trustworthy Embedded Systems with Rust
Firmware for hardware that cannot be patched in the field has a different cost of failure than an application you can restart.
-rw-r--r-- 4m Embedded GPIO (General Purpose Input / Output)
GPIO stands for general purpose input/output. It is a type of pin found on an integrated circuit that does not have a specific function.
-rw-r--r-- 16m Systems Understanding Memory Management in Rust: From Dynamically Sized Types to Fat Pointers
Rust handles memory through its type system, and a handful of questions follow.
-rw-r--r-- 7m Embedded From Rust source to embedded executable: the compilation process for embedded systems
This is the second part of my exploration into the stages and optimizations of Rust compilation, focusing now on embedded systems development.
-rw-r--r-- 6m Silicon The aesthetics of semiconductor destruction: understanding the PN junction
The PN junction is the fundamental building block of many semiconductor devices, from diodes to transistors and solar cells.
-rw-r--r-- 18m Embedded Critical compression of embedded firmware: understanding cargo size and linker strategies in Rust
Embedded Rust firmware is size constrained because the microcontroller has very little memory to spend.
-rw-r--r-- 6m Silicon Semiconductors: from atoms to crystals
Semiconductors sit between conductors and insulators, and their behavior comes down to how electrons are arranged in atoms.
-rw-r--r-- 17m Systems From Rust source code to optimized executable: inside the Rust compiler pipeline
Rust turns source code into a machine-executable binary through a pipeline of intermediate representations.
-rw-r--r-- 1m Making On-Chain Key-Value Storage note
An Anchor program that stores and updates user-defined key-value entries on-chain, a small favorites manager.
-rw-r--r-- 1m Making Anchor CPI: Cross-Program Invocation on Solana note
Two Anchor programs where one calls the other through a CPI, with a System Program transfer alongside it.
-rw-r--r-- 1m Making Game on Solana: Guess the Number note
A minimalist on-chain guessing game built with Rust and Anchor: the contract picks a number, the player guesses it.
-rw-r--r-- 1m Making Simple Solana Counter Program note
A minimal native Rust Solana program that increments and decrements an on-chain counter owned by the user's keypair.
-rw-r--r-- 3m Systems Actix-web AI Agent
RestOn is an agent that generates backend code from a text query. It is built in Rust on top of Actix-web.
-rw-r--r-- 2m Systems Rust Toolchain: A Complete Guide to Managing and Configuring Your Rust Environment note
How to manage Rust with rustup: release channels, toolchain overrides, components and build profiles.
-rw-r--r-- 2m Systems std web_server note
A multi-threaded HTTP server written with the Rust standard library only: thread pool, TCP listener and static file serving.
-rw-r--r-- 2m Systems Actix-Web Server note
An async RESTful notes service built with Actix-Web, Tokio, SQLx and SQLite: the architecture, the routes and the setup.
-rw-r--r-- 1m Making TUI Inventory App note
A terminal inventory manager built with Rust and Cursive: create, list and delete items, persisted in a flat JSON file.
-rw-r--r-- 1m Making TUI Pomodoro App note
A keyboard-driven Pomodoro timer built with Rust and Cursive, with a configurable session length and a minimal interface.
-rw-r--r-- 1m Systems Wasm-based Application: Tax Calculator note
A Rust and wasm-bindgen experiment: build a WebAssembly tax calculator and serve it from a static page.
-rw-r--r-- 2m Making Exploring C++ Game Development with Unreal Engine 5 note
Three C++ games built in Unreal Engine 5 - Dungeon Raider, Toon Tanks and ISSRiot - and what they taught me about level design.
-rw-r--r-- 1m Systems Android Emulator Launcher note
A Java Swing desktop app that creates and launches Android emulators, downloads missing system images and lists running devices.
-rw-r--r-- 1m Systems HTML Scraper note
A Spring Boot pipeline that fetches a page, parses it with Jsoup, maps the data to POJOs and writes an Excel file.
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