on call: Ajith, backend engineer
Bugs I hit, how I found the cause, and what I changed.
Real problems from Node.js, MongoDB, AWS, and Linux work, written up like incident reports, plus the AI developer tools I use.
- incidents
- 7
- resolved
- 7
- areas
- 5
$ whoami
ajith · backend engineer · node mongodb aws linux
$ tail -n 4 incidents.log
RESOLVEDSEP 17CLOUDWhy encodeURIComponent Breaks S3 CopyObject with Silent NoSuchKey Errors
RESOLVEDSEP 15NETSSH KEX Hang: A VPN Tunnel at MTU 1500 is not a Tunnel
$
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pinned write-ups
Building a Live Terminal Statusline for Claude Code: Tokens, Limits, and Responsive WrappingHow to design a resilient Bash statusline command for Claude Code that displays workspace context, token consumption, rolling rate limits, and ANSI color formatting without terminal overflow.
Silent Grouping: How a Missing Field in MongoDB $group Generates Plausible False PositivesWhy referencing a non-existent field in a MongoDB aggregation pipeline succeeds without error, collapses documents into deceptive buckets, and fools developers through coincidental count matches.Incident log
7 of 7 shown
- RESOLVEDSEP 17TOOLSBuilding a Live Terminal Statusline for Claude Code: Tokens, Limits, and Responsive WrappingHow to design a resilient Bash statusline command for Claude Code that displays workspace context, token consumption, rolling rate limits, and ANSI color formatting without terminal overflow.8 min read
- RESOLVEDSEP 17DBSilent Grouping: How a Missing Field in MongoDB $group Generates Plausible False PositivesWhy referencing a non-existent field in a MongoDB aggregation pipeline succeeds without error, collapses documents into deceptive buckets, and fools developers through coincidental count matches.6 min read
- RESOLVEDSEP 17CLOUDWhy encodeURIComponent Breaks S3 CopyObject with Silent NoSuchKey ErrorsHow a standard JavaScript URL encoding function silently breaks multi-segment S3 keys in CopyObjectCommand, producing deceptive NoSuchKey errors on objects that already exist.6 min read
- RESOLVEDSEP 15NETSSH KEX Hang: A VPN Tunnel at MTU 1500 is not a TunnelSSH connects, then dies mid-handshake. A local port-forward to a remote database cluster through a bastion stopped working, hanging on the first large packet of the SSH session. How an oversized MTU on a VPN interface created a silent black hole.12 min read
- RESOLVEDSEP 11LINUXTerminal System Diagnostics: A Complete Picture Without GUI ToolsHow to get a single complete picture of a machine's OS, boot mode, disk layout, memory, GPU, and network from one terminal pass, without guessing. A structured approach to hardware and OS discovery.11 min read
- RESOLVEDSEP 07NETAWS IAM Identity Center Sign-In Failure Caused by an MTU Black HoleWhen the AWS access portal loads but authentication hangs indefinitely, the fault may lie below the application layer. How a 1478-byte path MTU and dropped ICMP messages created a silent TLS handshake black hole.13 min read
- RESOLVEDSEP 03LINUXAWS IAM Identity Center Sign-In Failure Caused by Host Clock SkewA generic AWS sign-in error and a misleading password reset failure traced back not to IAM permissions or account status, but to a 5-hour local clock skew caused by dual-boot RTC desynchronization.10 min read
$ cat about.md
media.ajithakdev.com is written by Ajith Kumar Karudasevai, a backend engineer working with Node.js, TypeScript, MongoDB, and AWS. Every post is generalized: no private systems, internal endpoints, tickets, data models, or client details.
More about me and how I write →