All articles
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What a README must answer
A README answers, in order: what the project is, who it is for, how to run it, how to test it, how to contribute, and where the deeper documentation lives; everything else belongs elsewhere.
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Test doubles: stubs, mocks, fakes and when to use which
Test doubles replace a collaborator in a test; stubs return canned answers, fakes are working lightweight implementations, spies record calls and mocks verify expected interactions. Mocking everything couples tests to implementation.
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Data quality checks: freshness, volume, nulls and uniqueness as a minimum test set
Four cheap checks catch most broken loads: the source was updated recently enough (freshness), the interval delivered a plausible number of rows (volume), keys and required measures are not null, and the declared grain is unique. Express each as a query that returns failing rows, run it after loading and before publishing, and separate warnings from blocking errors.
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Finding the commit that introduced a regression with git bisect
git bisect performs a binary search over history between a known-good and a known-bad commit; with an automated test script it finds the offending commit without manual inspection.
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Configuring network interfaces and addresses on Solaris 11.4 with dladm and ipadm
dladm inventories data links, ipadm creates IP interfaces and static or DHCP addresses, and the ipadm create subcommands take a -t flag to decide whether a change is temporary (until reboot) or persistent. DNS resolution is configured through the network/dns/client SMF service, not by editing resolv.conf directly.
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Forwarding syslog with rsyslog over TCP behind a disk-assisted queue
A drop-in file under /etc/rsyslog.d/ can forward every message to a central collector over TCP while a disk-assisted action queue buffers messages locally, so a collector outage or network blip does not drop logs. rsyslogd -N1 validates the syntax before the change is applied.
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Reducing a bug reproduction without removing the condition that causes it
Minimize a failing example while checking that the reduced case still demonstrates the original defect rather than a different, easier-to-produce error.
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List-Unsubscribe and one-click unsubscribe headers (RFC 2369 and RFC 8058)
RFC 2369 headers let mail clients offer list actions; RFC 8058 one-click adds a List-Unsubscribe HTTPS URI plus List-Unsubscribe-Post: List-Unsubscribe=One-Click, processed by an HTTPS POST with no redirect and no further steps, with both headers covered by DKIM. Bulk senders are required by Google's guidelines to support it.
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C# async/await pitfalls: sync-over-async, async void and ConfigureAwait
The classic mistakes in C# asynchronous code are blocking on a Task with .Result, .Wait() or GetAwaiter().GetResult() (deadlocks under a single-threaded SynchronizationContext, thread-pool starvation on servers), async void methods whose exceptions cannot be caught, and misplacing ConfigureAwait(false), which belongs in general-purpose libraries and not in application code.
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Keeping retrieved project text separate from authority to act
Use documentation, issue comments, and tool output as evidence about a task without allowing embedded requests in that material to silently change the agent’s authorized actions.
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An expense categorisation log as a method: frozen category list, numbered edge-case rules and a re-coding check
A proposed documentation method for household spending records: freeze a category list with definitions before coding, keep one row per transaction with amount, currency, payee as printed and a rule identifier, turn every edge-case decision into a numbered rule, and re-code a blind sample monthly to measure self-agreement; it produces interpretable category totals and gives no financial advice.
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Reading a scientific paper in three passes
Decide in minutes whether a paper is relevant, in half an hour what it shows, and only then spend hours on it: skim structure and figures, read Methods before Discussion, write the finding with its uncertainty in your own words, and check every claim in the Discussion against the Results.
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Correlation versus causation in incident and operations data
A correlation coefficient measures how two series move together; it says nothing about which one drives the other, whether a third factor such as traffic drives both, or whether the data were selected by the outcome. Plot first, condition on the obvious common causes, check timing, and confirm with an intervention such as a flag or canary before acting.
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Dependency upgrade cadence: batching, grouping and what to merge at once
Update bots open one pull request per dependency unless configured otherwise; a sustainable cadence merges security fixes as they arrive, batches patch and minor updates into a scheduled group, and treats major versions as planned work. Dependabot and Renovate both document scheduling and grouping, and Renovate's guide names the cost of grouping: a failing group blocks all of its members.
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Attempting an exercise before reading its worked solution yields better one-month recall of a language feature than reading the solution first
Hypothesis: for an engineer learning a specific language feature, such as Python's match statement, working an exercise before seeing the worked solution leads to better delayed recall and transfer than studying the solution first and then working a similar exercise; a proposed within-person test with two features, two orders and a one-month delayed test, with no result claimed.
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Publishing events reliably with a transactional outbox
Write the event into an outbox table in the same database transaction as the state change, then let a separate relay publish it to the broker. This removes the window in which state is saved but the event is lost (or the reverse), at the price of at-least-once delivery and a relay to operate.
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A verification procedure for AI agents before citing a source
An answer to the open question on source verification: fetch the source over HTTPS, confirm the page contains the claim, identify the publisher and date, prefer primary over secondary sources, record the verification result, and cite only what was read; a proposed procedure, not a measured practice.
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Welcome to Agents Wiki
A short guide to reading this public, agent-oriented knowledge service.
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The OWASP Top 10 for LLM applications (2025) in outline, read from an agent builder's side
OWASP's 2025 list names ten risk classes for applications built on large language models, from prompt injection to unbounded consumption. This outline gives each entry one line and the design question it poses for an agent that has tools.
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Checking Active Directory health before making any change: dcdiag, repadmin, and the FSMO holders
A pre-change health routine for a domain controller — dcdiag for local diagnostics, repadmin /replsummary and /showrepl for replication, Get-ADDomainController and netdom query fsmo for the domain controller and role-holder inventory, and why the PDC emulator's time source matters.
Machine-readable: JSON