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Monitor and optimize the signer JAR size to stay under the 1 MB budget. Use when adding new classes or dependencies to signer/, or when the user is concerned about JAR size.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Build and test the burner-wallet monorepo. Runs signer (Java ME / Ant) and companion (Rust / Cargo) test suites. Use after making code changes to verify correctness, or when the user asks to run tests, build, or check the project.
Create a git commit following this project's Conventional Commits format with DCO sign-off. Use when the user asks to commit changes or when code changes are ready to be committed.
Verify that the Java ME signer and Rust companion produce identical outputs for the same cryptographic inputs. Use after modifying any BIP39/32/44/84/173 code in either signer/ or companion/core/, or when updating protocol/vectors/.
Security-focused review for cryptographic code in signer/ and companion/core/. Validates BIP standard compliance, checks for timing side-channels, verifies test vector coverage, and ensures cross-implementation consistency. Use when modifying files in signer/src/org/burnerwallet/core/, signer/src/org/burnerwallet/chains/, or companion/core/src/.
Enforces Java ME constraints when writing code in signer/. Prevents Java 5+ language features, validates CLDC 1.1 and MIDP 2.0 API usage, and monitors JAR size. Use whenever editing or creating Java files under signer/src/ or signer/test/.
Implementation guide for BIP174 PSBT (Partially Signed Bitcoin Transactions) on the Java ME signer. Reference for M1c milestone. Use when working on PSBT parsing, signing, or transaction construction in signer/src/org/burnerwallet/transport/ or signer/src/org/burnerwallet/chains/bitcoin/.
| name | size-monitor |
| description | Monitor and optimize the signer JAR size to stay under the 1 MB budget. Use when adding new classes or dependencies to signer/, or when the user is concerned about JAR size. |
The signer MIDlet must fit in a 1 MB JAR (1,048,576 bytes) to run on the Nokia C1-01. This includes all application classes AND the tree-shaken Bouncy Castle crypto library.
| Component | Size | Notes |
|---|---|---|
| Application classes | ~50 KB | 27 Java source files |
| Bouncy Castle (pruned) | ~236 KB | After ProGuard tree-shaking |
| Total JAR | ~286 KB | Well under budget |
| Budget remaining | ~738 KB | Available for M1c-M1e features |
make size-check
# Or manually:
ls -la signer/dist/BurnerWallet.jar 2>/dev/null
The build uses ProGuard 7.8.2 with -microedition. Key settings in signer/build.xml:
-injars (not -libraryjars) for aggressive tree-shaking-keep class org.burnerwallet.** preserves all app classes-keep class * extends javax.microedition.midlet.MIDlet preserves the entry pointCheck ProGuard output for which BC classes survived:
jar tf signer/dist/BurnerWallet.jar | grep bouncycastle | wc -l
Review unused imports in signer source that pull in BC classes:
grep -r "import org.bouncycastle" signer/src/ | sort -u
Consider splitting features across MIDlet suites (last resort)
Avoid adding new third-party libraries — every dependency goes through ProGuard
| Feature | Estimated Size Impact |
|---|---|
| PSBT parser | +15-25 KB |
| BIP143 sighash | +5-10 KB |
| QR code generator | +30-50 KB (depends on library) |
| QR code reader (camera) | +20-40 KB |
| Transaction serializer | +5-10 KB |
| Total M1c-M1e estimate | +75-135 KB |
| Projected total | ~360-420 KB |
Even with all planned features, we should stay well under 1 MB.
signer/src/signer/make test)