chore: optimize AI agent context and implement CI cost controls

- Modularize `AGENTS.md` by relocating detailed rules to the `.skills/` directory.
- Add `scripts/sort-strings.py` and `strings-index.txt` to organize and index string resources.
- Introduce CI cost control guidelines and a pre-commit `ai-guardrail.sh` to prevent binary and log leaks.
- Expand `.copilotignore`, `.aiexclude`, and `.gitattributes` to reduce context window usage and indexing costs.
- Establish `.agent_memory/session_context.md` for persistent task tracking and project state.
- Update `SKILL.md` for code reviews with specific Git and PR hygiene requirements.

Author: jamesarich

.agent_memory/session_context.md

@@ -0,0 +1,19 @@
+# Agent Session Context - Meshtastic Android
+
+## Current Project State
+- **Token Mitigation (Phase 1-3):** COMPLETE.
+- **Ignore Rules:** Stricter `.copilotignore` and `.aiexclude` are active.
+- **Instruction Optimization:** `AGENTS.md` is modularized (~3KB base).
+- **Cleanup:** 1.5GB of stale build artifacts and logs purged.
+- **Guardrails:** Pre-commit AI guardrail script installed in `scripts/`. CI Cost Control skill active.
+
+## Active Task History
+- **Task:** Mitigate astronomical Copilot token costs.
+- **Outcome:** Significantly reduced context tax by moving detailed rules to `.skills/` and ignoring binary/log artifacts.
+- **Next Steps:** None. Mitigation project finalized.
+
+## Golden Context
+- Always check `.skills/compose-ui/strings-index.txt` before reading `strings.xml`.
+- Run `python3 scripts/sort-strings.py` after adding strings to keep the index and file organized.
+- Always check `gh run list` before pushing.
+- Pre-commit hook `scripts/ai-guardrail.sh` protects against binary leaks.

.aiexclude

@@ -0,0 +1,36 @@
+# Standard AI exclusion list for Cursor, Windsurf, etc.
+# Mirroring .copilotignore for project-wide token discipline
+
+# Build & Generated
+**/build/**
+.gradle/
+.kotlin/
+**/generated/**
+
+# Agent Artifacts
+.agent_artifacts/
+.agent_refs/
+tmp/
+*.log
+
+# Media & Binaries
+**/*.png
+**/*.jpg
+**/*.jpeg
+**/*.webp
+**/*.svg
+**/*.ico
+**/*.gif
+**/*.mp3
+**/*.wav
+**/*.ogg
+**/*.pdf
+**/*.ttf
+**/*.otf
+**/*.jar
+**/*.aar
+**/*.apk
+
+# Resources (Indexing non-English strings is a token sink)
+**/values-*/strings.xml
+**/composeResources/**/values*/*.xml

.copilotignore

@@ -1,27 +1,54 @@
-# Ignore build artifacts and generated files from Copilot indexing
+# Meshtastic Android - GitHub Copilot Ignore List
 # This saves context window tokens and prevents Copilot from hallucinating off of minified code.
 
-# Build directories
+# ── Build & Generated ─────────────────────────────────────────────────────────
 **/build/**
 .gradle/
-.idea/
-
-# Android generated files
+.kotlin/
 **/generated/**
 .cxx/
 .externalNativeBuild/
 
-# Git history & worktrees
-.git/
-.worktrees/
-
-# Protobuf (Prevents Copilot from suggesting raw protobuf byte buffers)
-core/proto/
-
-# Environment and secrets
+# ── IDE & Environment ─────────────────────────────────────────────────────────
+.idea/
+.run/
+.claude/
+.gemini/
+.jdk
 local.properties
 secrets.properties
 *.jks
+.DS_Store
 
-# Agent References (Prevents pollution of project space with external code)
+# ── Agent Artifacts (Large volumes of logs/images) ───────────────────────────
+.agent_artifacts/
+# Note: .agent_plans/ is NOT ignored to maintain implementation context.
 .agent_refs/
+tmp/
+*.log
+
+# ── Binary Assets & Media ─────────────────────────────────────────────────────
+**/*.png
+**/*.jpg
+**/*.jpeg
+**/*.webp
+**/*.svg
+**/*.ico
+**/*.gif
+**/*.mp3
+**/*.wav
+**/*.ogg
+**/*.pdf
+**/*.ttf
+**/*.otf
+**/*.jar
+**/*.aar
+**/*.apk
+
+# ── External & Submodules ─────────────────────────────────────────────────────
+core/proto/
+
+# ── Resources ────────────────────────────────────────────────────────────────
+# Ignore translations (reduces churn and indexing tokens)
+**/values-*/strings.xml
+**/composeResources/**/values*/*.xml

.gitattributes

@@ -0,0 +1,13 @@
+# Mark resources as generated to reduce Copilot PR summary costs
+**/src/main/res/**/*.xml linguist-generated=true
+**/composeResources/**/*.xml linguist-generated=true
+**/strings.xml linguist-generated=true
+*.json linguist-generated=true
+
+# Ensure assets are treated as binary
+*.png binary
+*.jpg binary
+*.webp binary
+*.mp3 binary
+*.wav binary
+*.ogg binary

.skills/ci-cost-control/SKILL.md

@@ -0,0 +1,25 @@
+# Skill: CI Cost Control & Monitoring
+
+## Description
+Guidelines for agents to minimize GitHub Actions compute waste and prevent redundant or failing CI runs.
+
+## Rules
+
+### 1. Check Before You Kick
+Before pushing code that triggers a CI workflow, you **MUST** check if a relevant run is already in progress:
+```bash
+gh run list --branch $(git branch --show-current) --limit 5
+```
+- If a run is pending/running for your current state, **DO NOT** push again unless you are fixing a specific CI failure.
+- Cancel redundant runs if your new push supersedes them: `gh run cancel <run_id>`.
+
+### 2. Local First
+NEVER use CI as a "remote compiler." 
+- You must run `./gradlew spotlessCheck detekt test` locally before pushing.
+- If local tests fail, CI **will** fail. Do not waste the tokens or the compute.
+
+### 3. Modular CI Invocations
+When using the `/delegate` or autonomous PR tools, explicitly limit the scope of the CI check if the tool supports it. Avoid running the full multi-OS desktop matrix for a simple documentation fix.
+
+## Monitoring
+Use `gh run view <run_id>` to inspect failures. Do not re-run a whole suite if only one shard failed due to a known flake; use `gh run rerun --failed`.

.skills/code-review/SKILL.md

@@ -64,3 +64,8 @@ When reviewing code, meticulously verify the following categories. Flag any devi
 2. **Reference the Docs:** Cite `AGENTS.md` and project architecture playbooks to justify change requests (e.g., "Per AGENTS.md, `java.io.*` cannot be used in `commonMain`; please migrate to Okio").
 3. **Enforce Build Health:** Remind authors to run `./gradlew test allTests` locally to verify changes, especially since KMP `test` tasks are ambiguous.
 4. **Praise Good Patterns:** Acknowledge correct usage of complex architecture requirements, like proper Navigation 3 scene transitions or elegant `commonMain` helper extractions.
+
+## Git & PR Hygiene Rules
+- **Commit Hygiene:** Squash fixup/polish/review-feedback commits before opening a PR. Each commit should represent a logical, self-contained unit of work — not a back-and-forth conversation.
+- **PR Descriptions:** Keep PR descriptions concise and scannable. State *what changed* and *why*, not a per-commit play-by-play. Use a short summary paragraph followed by a bullet list of changes. Avoid tables, headers-per-commit, or verbose breakdowns. Reference the `meshtastic/firmware` repo PRs for tone and style.
+- **PR Titles:** Use conventional commit format: `feat(scope):`, `fix(scope):`, `refactor(scope):`, `chore(scope):`. Keep titles under ~72 characters.