diff --git a/.agents/memory/ACTIVE/PLAN.md b/.agents/memory/ACTIVE/PLAN.md
new file mode 100644
index 0000000..e0a3f3f
--- /dev/null
+++ b/.agents/memory/ACTIVE/PLAN.md
@@ -0,0 +1,28 @@
+# Plan: <topic>
+
+## Outcome
+
+What "done" looks like in one sentence.
+
+## Motivation
+
+What problem this solves and why it matters, with user scenarios, project context, and background in the problem space. 
+
+## Constraints
+
+- Runtime and compatibility constraints
+- Public API surface constraints
+- `deno lint` compliance required throughout
+- `deno doc --lint` compliance required throughout
+
+## Non-goals
+
+What is explicitly out of scope.
+
+## Approach
+
+A short narrative of the design at a high level.
+
+## Key decisions
+
+Link to ADRs in `../DECISIONS/` when needed.
diff --git a/.agents/memory/ACTIVE/PROGRESS.md b/.agents/memory/ACTIVE/PROGRESS.md
new file mode 100644
index 0000000..420e2f9
--- /dev/null
+++ b/.agents/memory/ACTIVE/PROGRESS.md
@@ -0,0 +1,21 @@
+# Progress
+
+## Current status
+
+- Today's focus: <one sentence>
+- Next task: T0X
+- Blockers: <none | list>
+
+## Completed
+
+- [x] T01: <title> (commit: <sha or PR link if known>)
+
+## Notes for the next agent
+
+- Assumptions made:
+  - <assumption>
+- Files touched:
+  - <path>
+- Verification to run:
+  - `deno task test`
+  - `deno doc --lint mod.ts`
diff --git a/.agents/memory/ACTIVE/RISKS.md b/.agents/memory/ACTIVE/RISKS.md
new file mode 100644
index 0000000..04f03ad
--- /dev/null
+++ b/.agents/memory/ACTIVE/RISKS.md
@@ -0,0 +1,13 @@
+# Risks
+
+## Known risks
+
+- <risk and why it matters>
+
+## Mitigations
+
+- <how to validate or reduce the risk>
+
+## Follow-ups
+
+- <future check or improvement>
diff --git a/.agents/memory/ACTIVE/TASKS.md b/.agents/memory/ACTIVE/TASKS.md
new file mode 100644
index 0000000..62ad99b
--- /dev/null
+++ b/.agents/memory/ACTIVE/TASKS.md
@@ -0,0 +1,18 @@
+# Tasks
+
+Rules:
+- Each task is small enough to complete in one iteration.
+- Each task has clear, verifiable acceptance checks.
+
+## Queue
+
+- [ ] T01: <task title>
+  - Why: <one sentence>
+  - Done when:
+    - [ ] `deno task test` passes
+    - [ ] `deno doc --lint mod.ts` passes
+    - [ ] <additional verifiable condition>
+
+## Parking lot
+
+- [ ] P01: <deferred idea>
diff --git a/.agents/memory/CHECKLISTS/pr-checklist.md b/.agents/memory/CHECKLISTS/pr-checklist.md
new file mode 100644
index 0000000..ac7c361
--- /dev/null
+++ b/.agents/memory/CHECKLISTS/pr-checklist.md
@@ -0,0 +1,26 @@
+# PR Checklist
+
+## Intent
+
+- [ ] The PR title and description explain outcome, problem, and motivation.
+- [ ] The title follows Conventional Commit format (see
+      `pull-requests.instructions.md`).
+
+## Changes
+
+- [ ] Changes are scoped to the stated intent.
+- [ ] Risky or breaking behavior changes are called out explicitly.
+
+## Verification
+
+- [ ] `deno task test` passes.
+- [ ] `deno task bench` passes.
+- [ ] `deno doc --lint mod.ts` passes with no errors.
+- [ ] Failure modes and error paths were considered.
+
+## Documentation
+
+- [ ] TSDoc is updated for any changed public API.
+- [ ] `readme.md` updated if user-facing behavior changed.
+- [ ] `changelog.md` entry added (or will be generated by forge).
+- [ ] Decisions that affect contracts are captured in an ADR.
diff --git a/.agents/memory/CHECKLISTS/release-checklist.md b/.agents/memory/CHECKLISTS/release-checklist.md
new file mode 100644
index 0000000..1a18cf9
--- /dev/null
+++ b/.agents/memory/CHECKLISTS/release-checklist.md
@@ -0,0 +1,25 @@
+# Release Checklist
+
+## Scope
+
+- [ ] Release intent is documented in `changelog.md`.
+- [ ] Backwards compatibility risks are identified and called out.
+
+## Artifacts
+
+- [ ] Version bumped via `deno task forge bump`.
+- [ ] Changelog entries are accurate and human-readable.
+- [ ] Breaking changes are prominently marked with migration paths.
+
+## Validation
+
+- [ ] `deno task test` passes on the release commit.
+- [ ] `deno task bench` passes on the release commit.
+- [ ] `deno doc --lint mod.ts` passes with no errors.
+- [ ] JSR publish dry-run: `deno publish --dry-run`.
+- [ ] npm build succeeds: `deno task build:npm`.
+
+## Rollback
+
+- [ ] Rollback plan is clear if a regression is found post-publish.
+- [ ] Yanked releases are marked in `changelog.md` with a note.
diff --git a/.agents/memory/CHECKLISTS/review-checklist.md b/.agents/memory/CHECKLISTS/review-checklist.md
new file mode 100644
index 0000000..1a17913
--- /dev/null
+++ b/.agents/memory/CHECKLISTS/review-checklist.md
@@ -0,0 +1,24 @@
+# Review Checklist
+
+## Correctness
+
+- [ ] Behavior matches the stated intent.
+- [ ] Edge cases and error paths are handled explicitly (empty string, single
+      line, all whitespace, mixed line endings).
+
+## Safety
+
+- [ ] No unsafe patterns (eval, silent fallbacks, implicit coercions).
+- [ ] Trust boundaries are clear.
+
+## Maintainability
+
+- [ ] Naming is clear, intent-revealing, and consistent with the existing API.
+- [ ] Complex logic is explained with comments or ASCII diagrams.
+- [ ] `deno doc --lint mod.ts` still passes — no `private-type-ref` errors.
+
+## Verification
+
+- [ ] `deno task test` passes.
+- [ ] `deno doc --lint mod.ts` passes.
+- [ ] Verification steps are adequate for the stated change.
diff --git a/.agents/memory/CONVENTIONS.md b/.agents/memory/CONVENTIONS.md
new file mode 100644
index 0000000..7944083
--- /dev/null
+++ b/.agents/memory/CONVENTIONS.md
@@ -0,0 +1,30 @@
+# Conventions
+
+## Intent
+
+Capture conventions that agents should follow when working in this repo.
+
+## Context
+
+This repo values small, verifiable changes and file-based progress that
+survives context resets.
+
+## Constraints
+
+- Keep notes brief and actionable.
+- Do not store secrets or customer data.
+- Prefer explicit configuration and clear error handling.
+
+## Approach
+
+- Read `ACTIVE/PLAN.md` and `ACTIVE/TASKS.md` before starting multi-step work.
+- Update `ACTIVE/PROGRESS.md` after meaningful progress.
+- Mark tasks done only when acceptance checks pass.
+- Promote architectural decisions to ADRs in `DECISIONS/`.
+- Run `deno task test`, `deno task bench`, `deno lint` and `deno doc --lint mod.ts` before marking any
+  API-touching task complete.
+
+## Edge cases
+
+If work spans multiple iterations, capture risks in `ACTIVE/RISKS.md` to avoid
+context loss.
diff --git a/.agents/memory/DECISIONS/ADR-0001-template.md b/.agents/memory/DECISIONS/ADR-0001-template.md
new file mode 100644
index 0000000..558c8bb
--- /dev/null
+++ b/.agents/memory/DECISIONS/ADR-0001-template.md
@@ -0,0 +1,21 @@
+# ADR-0001: <decision title>
+
+## Context
+
+What prompted the decision.
+
+## Decision
+
+What we chose.
+
+## Rationale
+
+Why this choice over alternatives.
+
+## Consequences
+
+Trade-offs, risks, follow-ups.
+
+## Alternatives considered
+
+What we did not pick and why.
diff --git a/.agents/memory/GLOSSARY.md b/.agents/memory/GLOSSARY.md
new file mode 100644
index 0000000..29b6002
--- /dev/null
+++ b/.agents/memory/GLOSSARY.md
@@ -0,0 +1,15 @@
+# Glossary
+
+- **TSA** — Template Strings Array. The frozen array of string literals passed
+  as the first argument to a tagged template function.
+- **Dedent / undent / outdent** — the operation of removing the common leading
+  whitespace from every line of an indented string.
+- **Column offset** — the number of leading whitespace characters before the
+  first non-whitespace character on a line.
+- **LICM** — Loop Invariant Code Motion. A JIT optimization that hoists
+  loop-invariant computations out of the loop. Relevant to benchmark validity.
+- **TSDoc** — TypeScript documentation comment format (`/** ... */`) used by
+  `deno doc`.
+- **JSR** — Jsr.io, the TypeScript-native package registry for Deno.
+- **ADR** — Architecture Decision Record. A short document capturing a
+  significant design choice, its context, and the rationale.
diff --git a/.agents/memory/INDEX.md b/.agents/memory/INDEX.md
new file mode 100644
index 0000000..664493c
--- /dev/null
+++ b/.agents/memory/INDEX.md
@@ -0,0 +1,19 @@
+# Memory Index
+
+## Core references
+
+- [PROJECT](PROJECT.md)
+- [CONVENTIONS](CONVENTIONS.md)
+- [GLOSSARY](GLOSSARY.md)
+
+## Active work
+
+- [PLAN](ACTIVE/PLAN.md)
+- [TASKS](ACTIVE/TASKS.md)
+- [PROGRESS](ACTIVE/PROGRESS.md)
+- [RISKS](ACTIVE/RISKS.md)
+
+## Decisions and checklists
+
+- [DECISIONS](DECISIONS/)
+- [CHECKLISTS](CHECKLISTS/)
diff --git a/.agents/memory/PROJECT.md b/.agents/memory/PROJECT.md
new file mode 100644
index 0000000..81170fe
--- /dev/null
+++ b/.agents/memory/PROJECT.md
@@ -0,0 +1,30 @@
+# Project Summary
+
+## Outcome
+
+`@okikio/undent` is a single-module Deno library that strips source-code
+indentation from template literals and plain strings.
+
+## Context
+
+- Runtime: Deno v2, TypeScript (strict), ESM
+- Published to: JSR and npm
+- Entire public API lives in `mod.ts` — no separate build step
+
+## Key exports
+
+- **Tag functions** — `undent`, `dedent`, `outdent`, `createUndent`
+- **Value helpers** — `align`, `embed`, `isAligned`
+- **String/text utilities** — `dedentString`, `alignText`, `splitLines`,
+  `rejoinLines`, `columnOffset`, `newlineLengthAt`, `resolveOptions`, `DEFAULTS`
+
+## Constraints
+
+- All public API types must be exported (enforced by `deno doc --lint`).
+- No hidden global state; no top-level side effects.
+- Keep the module tree-shakeable.
+
+## Non-goals
+
+This file is not a full API spec or changelog. See `mod.ts` TSDoc and
+`readme.md` for those.
diff --git a/.agents/memory/README.md b/.agents/memory/README.md
new file mode 100644
index 0000000..a79799b
--- /dev/null
+++ b/.agents/memory/README.md
@@ -0,0 +1,22 @@
+# Agent Memory
+
+This directory stores file-based state for agent work so progress survives
+context resets. Durable notes that teammates can rely on live in the top-level
+files and the `ACTIVE`, `DECISIONS`, and `CHECKLISTS` folders. Scratch notes
+live under `SESSIONS` and are gitignored.
+
+## Constraints
+
+- Do not store secrets, tokens, private URLs, or customer data.
+- Keep `ACTIVE` short and current; archive completed work.
+- Prefer small, verifiable tasks that can be completed in one iteration.
+
+## Approach
+
+Use `ACTIVE` as the control panel for ongoing work, `DECISIONS` for long-lived
+architectural choices, and `CHECKLISTS` for repeatable quality gates.
+
+## Edge cases
+
+If `TASKS` grows too large, split into multiple files or an epic folder. If a
+decision affects the public API or documented behavior, promote it to an ADR.
diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 0b420ba..21ef250 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -146,3 +146,5 @@ Targeted rules live under `.github/instructions/`:
 | `testing.instructions.md`           | `**/*_test.ts`, `**/*.test.ts`   |
 | `benchmarking.instructions.md`      | `**/*_bench.ts`, `**/*bench*.ts` |
 | `changelog-commits.instructions.md` | `**` (all files)                 |
+| `pull-requests.instructions.md`     | `**` (all files)                 |
+| `code-review.instructions.md`       | `**` (all files)                 |
diff --git a/.github/instructions/code-review.instructions.md b/.github/instructions/code-review.instructions.md
new file mode 100644
index 0000000..7cd14d2
--- /dev/null
+++ b/.github/instructions/code-review.instructions.md
@@ -0,0 +1,53 @@
+---
+description: Code review standards for this repo
+applyTo: "**"
+---
+
+# Code Review
+
+Prioritize correctness, clarity, maintainability, and standards alignment.
+Avoid noise: fewer, higher-signal comments.
+
+## Review rubric (in order)
+
+### 1. Correctness & contracts
+
+- Does the code do what it claims?
+- Are edge cases handled (empty string, single line, mixed line endings, all
+  whitespace, no indentation)?
+- Are public API contracts consistent across call site and implementation?
+
+### 2. Failure modes & safety
+
+- Are errors explicit? No silent fallbacks or implicit coercions.
+- Any unsafe patterns (eval, unvalidated inputs, string-built operations)?
+- Does the change affect `deno doc --lint` compliance?
+
+### 3. Types & narrowing
+
+- Avoid `any`. Prefer generics, unions, discriminated unions, and narrowing.
+- Every type referenced in a public signature must itself be exported —
+  `deno doc --lint` will catch `private-type-ref` errors.
+- Return types at module boundaries should be explicit and narrow.
+
+### 4. Readability & educational clarity
+
+- Naming should be approachable and intent-revealing. See naming rules in
+  `copilot-instructions.md`.
+- Comments should explain _why_. For non-obvious logic (regex, bitwise, tricky
+  boolean), also explain _what/how_ in plain English.
+- If the change's intent isn't obvious from the diff, suggest improving:
+  - naming and/or docstrings
+  - OR the PR description to clearly state motivation and impact
+
+### 5. Consistency & style
+
+Match repo formatting and import conventions. See `typescript.instructions.md`.
+
+## Output format
+
+Use tags: `[BLOCKER]`, `[IMPORTANT]`, `[SUGGESTION]`, `[NIT]`
+
+- Provide a concrete fix suggestion for every `[BLOCKER]` and `[IMPORTANT]`.
+- Avoid generic feedback like "improve quality" — tie every comment to a
+  specific behavior, risk, or readability issue.
diff --git a/.github/instructions/pull-requests.instructions.md b/.github/instructions/pull-requests.instructions.md
new file mode 100644
index 0000000..2452e88
--- /dev/null
+++ b/.github/instructions/pull-requests.instructions.md
@@ -0,0 +1,65 @@
+---
+description: PR title, description, and design doc standards for this repo
+applyTo: "**"
+---
+
+# Pull Requests
+
+## Title
+
+Use Conventional Commit style: `type(scope optional): outcome`
+
+- Prefer outcome-focused summaries ("prevent double-stripping on nested undent
+  calls")
+- Avoid vague titles ("update mod.ts", "misc fixes")
+- The title must describe an observable outcome (behavior, contract, or
+  workflow), not "add guidelines / improve quality"
+- See `changelog-commits.instructions.md` for type/scope/breaking-change rules
+
+## Description
+
+Write for reviewers and future archaeology. Be concrete.
+
+**Summary** — 1–3 bullets: what changed and in which module/function.
+No generic goals like "improve quality" unless tied to a specific behavior
+change.
+
+**Problem / Motivation** — the real issue. Anchor it: "Before, X happened…" /
+"Callers couldn't…" / "The output was wrong when…"
+
+**Solution** — what changed at a high level and where (files/functions).
+
+**Behavior changes** — if anything observable changes, list it plainly:
+
+- output shape changes
+- edge case handling changes
+- breaking API changes (see `changelog-commits.instructions.md`)
+- performance / allocation changes
+
+**Verification** — list `deno task test` and `deno doc --lint mod.ts`, plus any
+manual checks. If not verified, say "Should verify by…" — don't claim you ran
+them.
+
+**Risk & rollout** (when relevant) — what could break, edge cases, mitigations.
+
+## Writing constraints
+
+- Short bullets and concrete nouns.
+- Avoid memo-speak ("enhance process", "ensure quality", "various aspects").
+- Do not invent issue numbers, links, or test results.
+
+## Design docs and specs
+
+When a PR introduces a non-trivial behavioral change or a new public API,
+include a design note using RFC structure:
+
+1. **Problem** — what is broken or missing
+2. **Goals / Non-goals** — scope and explicit exclusions
+3. **Constraints** — runtime, compatibility, performance, security
+4. **Proposal** — the approach, with ASCII diagrams if helpful
+5. **Alternatives considered** — why not the other options
+6. **Edge cases & failure modes**
+7. **Open questions**
+
+Prefer concrete examples over abstract statements. Call out trade-offs
+explicitly. Keep decision points obvious so reviewers can challenge them.