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 skills add OutlineDriven/outline-driven-development --skill abi-and-calling-conventionsgit clone --depth 1 https://github.com/OutlineDriven/outline-driven-developmentWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/outlinedriven/outline-driven-development/abi-and-calling-conventions)<a href="https://agentmods.dev/skills/outlinedriven/outline-driven-development/abi-and-calling-conventions"><img src="https://agentmods.dev/badge/skills/outlinedriven/outline-driven-development/abi-and-calling-conventions/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/outlinedriven/outline-driven-development/abi-and-calling-conventions"><img src="https://agentmods.dev/badge/skills/outlinedriven/outline-driven-development/abi-and-calling-conventions.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What 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 5.1 | $0.00053 | $0.01325 |
| Opus 5 | $0.00026 | $0.00662 |
| Sonnet 5 | $0.00011 | $0.00265 |
| Haiku 4.5 | $0.00005 | $0.00133 |
Grade A, and why
abi-and-calling-conventions 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 3d 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 — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ABI and calling conventions
Contract
| Field | Bound contract |
|---|---|
| Trigger | A question or debugging session needs the register roles, stack alignment, argument passing, return value, or variadic rules of System V AMD64, ARM AAPCS, or the RISC-V psABI. |
| Authority | Read-only. The skill reads source, disassembly, and compiler output and answers in chat. Nothing on disk changes, so there is nothing to roll back. No remote mutation. |
| Side effect | Chat output only. Compiler and disassembler runs write nothing outside stdout. |
| Done | The answer names the argument registers, return registers, stack alignment, callee-saved set, and variadic rule for the named ABI, and points to the compiler output that confirms it. |
Inputs
- Target ABI (required): System V AMD64, AAPCS64 (AArch64), or RISC-V psABI (RV64). If the user names Windows x64, see the failure table.
- Calling context (required): an assembly thunk, inline asm clobber list, a mixed C and assembly boundary, a variadic wrapper, or an FFI signature.
- Symptom (optional): a crash on
call, a wrong argument value, or a corrupted register after a call.
Procedure
- Name the ABI from the toolchain target and the platform. Done when: one of the three ABIs is named, or the failure table applies.
- State the register contract for that ABI. Done when: argument, return, alignment, and callee-saved rows are all given.
| ABI | Integer arguments | Float or vector arguments | Return | Stack alignment at call | Callee-saved |
|---|---|---|---|---|---|
| System V AMD64 | rdi, rsi, rdx, rcx, r8, r9 |
xmm0 to xmm7 |
rax (xmm0 for float or vector), plus rdx for 128-bit values |
16 bytes before call |
rbx, rbp, r12 to r15, rsp |
| AAPCS64 | x0 to x7 |
v0 to v7 |
x0 and x1, or v0 |
16 bytes | x19 to x28, x29 (frame pointer), sp |
| RISC-V psABI RV64 | a0 to a7 |
fa0 to fa7 |
a0 and a1 (fa0 for float) |
16 bytes | s0 to s11, sp |
System V AMD64 on Linux also grants a 128-byte red zone below rsp that leaf functions use without adjusting the stack pointer. Arguments past the register set go on the stack, so a seven-integer C function on System V passes the seventh in memory.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 3d ago First seen · 63 lines · 53 tokens per session scan A 4fa34613be6a
abi-and-calling-conventions is a skill published in the GitHub repository OutlineDriven/outline-driven-development (52 stars, last pushed 3d ago), licensed Apache-2.0. It adds 53 tokens to every session and 1,325 once invoked, about $0.0003 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 2026-09-06.
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