Everything worth knowing, modelled.https://curiosity.local/https://curiosity.local/notes/0045/https://curiosity.local/notes/0045/Lectures from walkinglabs distilling the load-bearing claims about agent harnesses — why infrastructure outside the weights, not the model itself, governs how much capability gets realized.Thu, 28 May 2026 00:00:00 GMTharness-engineeringnewagentsharnesscoursereferencehttps://curiosity.local/notes/0043/https://curiosity.local/notes/0043/Generating token N means attending to tokens 1..N-1. Recomputing their key/value tensors every step turns O(n) work into O(n²). Caching K and V is what makes real-time LLM streaming possible.Wed, 27 May 2026 00:00:00 GMTllmnewllminferencetransformersperformancehttps://curiosity.local/notes/0035/https://curiosity.local/notes/0035/Claude Code navigates code with grep by default — slow and fuzzy. Enabling the official LSP plugins gives the agent semantic goToDefinition and findReferences instead. Install, enable, restart.Wed, 27 May 2026 00:00:00 GMTclaude-codenewclaude-codelsppluginsproductivityhttps://curiosity.local/notes/0034/https://curiosity.local/notes/0034/Reverse-engineered from npm source maps, these 10 design decisions explain why Claude Code is fast, safe, and recoverable under production conditions.Wed, 27 May 2026 00:00:00 GMTclaude-codenewclaude-codearchitectureinternalsagentsreferencehttps://curiosity.local/notes/0031/https://curiosity.local/notes/0031/Submodules embed one repo inside another by pinning a commit, not a branch. Knowing that single fact prevents most of the pain — detached HEADs, missed pushes, and silent divergence after a pull.Tue, 26 May 2026 00:00:00 GMTgitgitdependencieshttps://curiosity.local/notes/0030/https://curiosity.local/notes/0030/How the three dominant branching models differ in branch count, integration cadence, and release rhythm — and how to pick one based on your release model, not the model's brand.Tue, 26 May 2026 00:00:00 GMTgitgitworkflowhttps://curiosity.local/notes/0029/https://curiosity.local/notes/0029/Treat each commit (or tiny branch) as the unit of review, not a large feature branch. Smaller reviews, less waiting, better commit hygiene — and a non-trivial rebase tax to pay.Tue, 26 May 2026 00:00:00 GMTgitgitreviewworkflowhttps://curiosity.local/notes/0028/https://curiosity.local/notes/0028/Local-only ignores, untracking already-tracked files, hiding local edits to tracked files, and a global ignore for OS junk — the four problems .gitignore alone doesn't solve.Tue, 26 May 2026 00:00:00 GMTgitgitworkflowhttps://curiosity.local/notes/0027/https://curiosity.local/notes/0027/Binary search across commit history to find the first bad commit. Works manually or fully automated with a script — turning a needle-in-a-haystack search into log2(n) steps.Tue, 26 May 2026 00:00:00 GMTgitgitdebugginghttps://curiosity.local/notes/0026/https://curiosity.local/notes/0026/Interactive rebase, soft reset, and merge --squash all collapse commits into fewer commits. They differ in granularity, on which branch they leave the result, and how much history they preserve.Tue, 26 May 2026 00:00:00 GMTgitgithistoryhttps://curiosity.local/notes/0025/https://curiosity.local/notes/0025/What rebase actually does to your commits, how to drive the interactive form, and the recovery moves that keep a bad rebase from becoming a lost-work incident.Tue, 26 May 2026 00:00:00 GMTgitgithistoryhttps://curiosity.local/notes/0024/https://curiosity.local/notes/0024/How and when to use git worktree to keep multiple branches checked out at once, sharing one object store, without the disk cost or coordination headaches of multiple clones.Tue, 26 May 2026 00:00:00 GMTgitgitworkflowhttps://curiosity.local/notes/0023/https://curiosity.local/notes/0023/Secrets Manager charges two ways at once: a flat per-secret-month fee plus a per-API-call fee. Understanding the split is what lets you predict the bill and decide whether to cache.Mon, 25 May 2026 00:00:00 GMTdevopsawssecrets-managercosthttps://curiosity.local/notes/0022/https://curiosity.local/notes/0022/Four `nslookup` recipes for verifying that the CNAME, MX, and TXT records you published for CloudFront, ACM, SES DKIM, and SES MAIL FROM actually resolve before AWS does.Mon, 25 May 2026 00:00:00 GMTdevopsawsdnsnslookupsesacmcloudfronthttps://curiosity.local/notes/0021/https://curiosity.local/notes/0021/How AWS Certificate Manager proves you control a domain before issuing a TLS cert: ACM publishes a `_<hash>.domain` CNAME challenge, you copy it to DNS, and renewal stays automatic forever after.Mon, 25 May 2026 00:00:00 GMTdevopsawsacmdnstlshttps://curiosity.local/notes/0020/https://curiosity.local/notes/0020/Why DMARC alignment forces you to publish a custom MAIL FROM subdomain in SES, and how to set up the MX + SPF records that prove SES can send on its behalf.Mon, 25 May 2026 00:00:00 GMTdevopsawssesdnsemaildmarchttps://curiosity.local/notes/0019/https://curiosity.local/notes/0019/How AWS SES proves you own a sending domain: three CNAME tokens published to your DNS host let SES sign outbound mail with DKIM on your behalf.Mon, 25 May 2026 00:00:00 GMTdevopsawssesdnsemailhttps://curiosity.local/notes/0018/https://curiosity.local/notes/0018/The seven-step dance behind 'Log in with Google'. Why the redirects exist, why the code is swapped for the token server-to-server, and where PKCE plugs the public-client hole.Mon, 25 May 2026 00:00:00 GMTsystem-designsecurityauthenticationoauthidentityhttps://curiosity.local/notes/0017/https://curiosity.local/notes/0017/When you stop asking users for a password, what do you verify instead? Three answers — OTP proves channel ownership, SSO and OAuth/OIDC delegate identity to a trusted issuer.Mon, 25 May 2026 00:00:00 GMTsystem-designsecurityauthenticationidentityhttps://curiosity.local/notes/0016/https://curiosity.local/notes/0016/How a server remembers an authenticated user across HTTP's stateless requests — Basic resends credentials, session cookies pin server-side state, tokens carry signed claims. The tradeoffs that pick one.Mon, 25 May 2026 00:00:00 GMTsystem-designsecurityauthenticationhttphttps://curiosity.local/notes/0015/https://curiosity.local/notes/0015/PGP gives you two independent guarantees — secrecy via encryption with the recipient's public key, and authenticity via signing with your own private key. Most production uses want both, in that order.Mon, 25 May 2026 00:00:00 GMTsystem-designsecuritycryptographyencryptionhttps://curiosity.local/notes/0014/https://curiosity.local/notes/0014/Why passwords are hashed, never encrypted; why fast hashes like SHA-256 are wrong for this job; and how Argon2id / bcrypt / scrypt buy you decades against an attacker with the database.Mon, 25 May 2026 00:00:00 GMTsystem-designsecurityauthenticationcryptographyhttps://curiosity.local/notes/0013/https://curiosity.local/notes/0013/Combine several signals into one comparable score by normalising each to [0,1] and taking a weighted sum. The maths is trivial; the trap is mixing raw, unbounded quantities and letting one signal dominate the rest.Mon, 25 May 2026 00:00:00 GMTsystem-designrankingsearchrecommendationhttps://curiosity.local/notes/0012/https://curiosity.local/notes/0012/How consistent hashing distributes keys across a changing set of nodes while keeping the number of re-mapped keys proportional to the change — and why naive modulo sharding falls apart the moment a node joins or leaves.Mon, 25 May 2026 00:00:00 GMTsystem-designdistributed-systemscachingshardinghttps://curiosity.local/notes/0011/https://curiosity.local/notes/0011/Sharding adds an order of magnitude of complexity. Exhaust the cheaper options first — split the DB onto its own host, add a cache, add read replicas, scale the box up — and only shard when those run out.Sun, 24 May 2026 00:00:00 GMTmysqlscalingreplicationcachingarchitecturehttps://curiosity.local/notes/0010/https://curiosity.local/notes/0010/How to create a least-privilege MySQL account for analytics or support — and the specific grants, host restrictions, and cleanup steps that keep it least-privilege over time.Sun, 24 May 2026 00:00:00 GMTmysqlsecuritypermissionsoperationshttps://curiosity.local/notes/0009/https://curiosity.local/notes/0009/ALGORITHM=INPLACE, LOCK=NONE lets DDL run while reads and writes continue. Works for many but not all alterations — knowing which is the difference between zero downtime and a stuck production.Sun, 24 May 2026 00:00:00 GMTmysqlddlonline-ddloperationshttps://curiosity.local/notes/0008/https://curiosity.local/notes/0008/For matching a column against several values, IN beats OR by orders of magnitude (binary search vs linear), and BETWEEN beats IN when the values form a contiguous range.Sun, 24 May 2026 00:00:00 GMTmysqlsqlindexingwhere-clausehttps://curiosity.local/notes/0007/https://curiosity.local/notes/0007/How to read the EXPLAIN plan column by column — type, key, rows, filtered, Extra — what the values mean, what to fix, and how the driving table cascades through JOINs.Sun, 24 May 2026 00:00:00 GMTmysqlsqlexplainquery-planningindexinghttps://curiosity.local/notes/0006/https://curiosity.local/notes/0006/JOIN multiplies rows then dedupes; EXISTS short-circuits at the first match. For pure filtering, EXISTS is the semantically correct choice — no DISTINCT, no optimizer roulette.Sun, 24 May 2026 00:00:00 GMTmysqlsqljoinsexistsquery-planninghttps://curiosity.local/notes/0005/https://curiosity.local/notes/0005/The logical order MySQL runs your SELECT — FROM/JOIN, WHERE, GROUP BY, HAVING, SELECT, ORDER BY/LIMIT — and the optimization hook each stage gives you.Sun, 24 May 2026 00:00:00 GMTmysqlsqloptimizationindexingsargablehttps://curiosity.local/notes/0004/https://curiosity.local/notes/0004/When and how to use Claude Code's /compact — what it actually does, the signals that say it's time, and the prompt patterns that produce a clean handoff.Sun, 24 May 2026 00:00:00 GMTclaude-codenewclaude-codecontextproductivityslash-commandshttps://curiosity.local/notes/0000/https://curiosity.local/notes/0000/Every block in the Curiosity library, demonstrated. Doubles as a live styleguide and as the prompt context for an agent creating new notes.Sun, 24 May 2026 00:00:00 GMTmetaauthoringblocksreferencehttps://curiosity.local/notes/0001/https://curiosity.local/notes/0001/Why lazy associations trigger N+1 queries, how to detect them, and the four standard fixes.Wed, 20 May 2026 00:00:00 GMTjavajpahibernateperformancesqlhttps://curiosity.local/notes/0003/https://curiosity.local/notes/0003/Why every non-GET endpoint that touches money or external state needs an idempotency key, and how to implement one without footguns.Sat, 09 May 2026 00:00:00 GMTsystem-designapireliabilitydistributed-systemshttps://curiosity.local/notes/0002/https://curiosity.local/notes/0002/Subagents are not just for parallelism — their real value is keeping irrelevant tool output out of the parent conversation.Sat, 18 Apr 2026 00:00:00 GMTclaude-codeagentscontextproductivity