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 instructions/paulrberg/prb-math/agents-mdgit clone --depth 1 https://github.com/PaulRBerg/prb-mathWrote 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/instructions/paulrberg/prb-math/agents-md)<a href="https://agentmods.dev/instructions/paulrberg/prb-math/agents-md"><img src="https://agentmods.dev/badge/instructions/paulrberg/prb-math/agents-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00664 | $0.00664 |
| Opus 5 | $0.00332 | $0.00332 |
| Sonnet 5 | $0.00133 | $0.00133 |
| Haiku 4.5 | $0.00066 | $0.00066 |
Grade A, and why
prb-math AGENTS.md 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 4d 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 — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.
PRBMath
Solidity library for advanced fixed-point math with signed (SD59x18) and unsigned (UD60x18) 18-decimal types.
Stack
- Solidity 0.8.30
- Foundry (forge build, forge test, forge fmt)
- Bun for package management
- Prettier, Solhint for formatting/linting
Structure
src/
Common.sol # Shared utilities (mulDiv, exp2, log2, pow, sqrt)
SD59x18.sol # Signed 59.18 fixed-point type (entry point)
UD60x18.sol # Unsigned 60.18 fixed-point type (entry point)
SD1x18.sol, UD2x18.sol, SD21x18.sol, UD21x18.sol # Compact/medium types
sd59x18/, ud60x18/ # Core type ops (Casting, Constants, Helpers, Math, ValueType)
sd1x18/, ud2x18/, sd21x18/, ud21x18/ # Compact/medium type dirs
casting/ # Casting from uint40/uint128/uint256
test/
unit/ # Unit tests
fuzz/ # Fuzz tests
utils/ # Assertions and test utilities
Commands
just build- Build with Forgejust test- Run tests (forge test)just full-check- Prettier + Solhint + Forge format checkjust full-write- Auto-fix all formatting issues
Development
After generating or updating code:
- Run
just full-checkto verify - If errors, run
just full-writeto auto-fix - Fix remaining issues manually
Install dependencies: bun install or bun install -d <pkg> for dev deps.
Code Style
- Use user-defined value types (SD59x18, UD60x18) for type safety
- Free functions over library pattern
- Custom errors over require strings
- NatSpec comments on public functions
- Line length: 132 chars
- 4-space tabs
- Bracket spacing enabled
Fixed-Point Formats
| Type | Signed | Integer Digits | Decimals |
|---|---|---|---|
| SD59x18 | Yes | 59 | 18 |
| UD60x18 | No | 60 | 18 |
| SD1x18 | Yes | 1 | 18 |
| UD2x18 | No | 2 | 18 |
| SD21x18 | Yes | 21 | 18 |
| UD21x18 | No | 21 | 18 |
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.
- 4d ago First seen · 75 lines · 664 tokens per session scan A 27145416dc38
prb-math AGENTS.md is an instructions file published in the GitHub repository PaulRBerg/prb-math (1,006 stars, last pushed 20d ago), licensed MIT. It adds 664 tokens to every session, about $0.0033 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.
Other instructions, from other repositories
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foundry-template AGENTS.md
Instructions for PaulRBerg/foundry-template, covering agents.md, stack, commands, forge and bun scripts (package.json).
mcp-tenderly CLAUDE.md
Claude Code instructions for py-zoid/mcp-tenderly, covering mcp-tenderly, commands, layout, constraints worth knowing before you change anything and testing against real tenderly.
foundry-template CLAUDE.md
Instructions for PaulRBerg/foundry-template, a project described as: Foundry-based template for developing Solidity smart contracts.
tevm CLAUDE.md
Claude Code instructions for evmts/tevm, covering tevm monorepo commands and style guide, project overview, forking implementation, json-rpc support and commands.