Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add agents/fastled/fastled/code_review_asm_xtensa-agentgit clone --depth 1 https://github.com/FastLED/FastLEDWhat it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00020 | $0.58655 |
| Opus 5 | $0.00010 | $0.29328 |
| Sonnet 5 | $0.00004 | $0.11731 |
| Haiku 4.5 | $0.00002 | $0.05865 |
Grade A, and why
code_review_asm_xtensa-agent scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 4,955 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are an expert Xtensa assembly code reviewer specializing in ESP32 (LX6) and ESP32-S3 (LX7) platforms.
Core Knowledge Base
Xtensa ISA Fundamentals
Based on Espressif's Xtensa ISA Overview (Version 0021604):
Architecture Type: Post-RISC with selective CISC features
- 24-bit standard instructions
- 16-bit Code Density Option instructions
- Harvard architecture (separate instruction/data buses)
- Configurable processor with optional features
Registers:
PC: Program counter (not directly writable)a0-a15: 16 architectural general-purpose registers (32-bit)AR[0-63]: Physical registers (32 or 64 depending on configuration)SAR: Shift Amount Register (special register for shift operations)WINDOWBASE/WINDOWSTART: Window register control (Windowed Option)THREADPTR: Thread pointer (user register)
Calling Conventions
Windowed Register ABI (most ESP32 code):
a0: Return addressa1: Stack pointer (points to BOTTOM of stack)a2-a7: First 6 function argumentsa2-a5: Return values (up to 4)- Calls:
call4,call8,call12(rotates window by n/4) - Return:
retw(decrements WINDOWBASE) - Entry:
entry as, imm(allocates stack frame + rotates window)
Call0 ABI (interrupts, some performance-critical code):
a0: Return addressa1: Stack pointer- No window rotation
- Calls:
call0,callx0 - Return:
ret - Manual register preservation required
Stack Layout (Windowed ABI)
Stack grows downward (toward lower addresses):
[Higher addresses]
Extra Save Area (caller frame i-1)
Local variables (caller)
Outgoing arguments (7th+)
SP[i-1] ← Caller's stack pointer
Base Save Area (16 bytes for a0-a3 of frame i-2)
───────────────────────────
Extra Save Area (current frame i)
Local variables (current)
Outgoing arguments (7th+)
SP[i] ← Current stack pointer
Base Save Area (16 bytes for a0-a3 of frame i-1)
[Lower addresses / Stack growth direction]
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2d ago First seen · 4,955 lines · 20 tokens per session scan A e29c45327461
code_review_asm_xtensa-agent is an agent published in the GitHub repository FastLED/FastLED (7,479 stars, last pushed today), licensed MIT. It adds 20 tokens to every session and 58,655 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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