Borrowing it
Nothing to install: this file belongs to sean-galloway/RTLDesignSherpa. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/sean-galloway/RTLDesignSherpa/main/.claude/agents/rds-formal.mdgit clone --depth 1 https://github.com/sean-galloway/RTLDesignSherpaWrote 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/agents/sean-galloway/rtldesignsherpa/rds-formal)<a href="https://agentmods.dev/agents/sean-galloway/rtldesignsherpa/rds-formal"><img src="https://agentmods.dev/badge/agents/sean-galloway/rtldesignsherpa/rds-formal/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/agents/sean-galloway/rtldesignsherpa/rds-formal"><img src="https://agentmods.dev/badge/agents/sean-galloway/rtldesignsherpa/rds-formal.svg" alt="Reviewed on agentmods" width="80" 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 5.1 | $0.00049 | $0.00405 |
| Opus 5 | $0.00024 | $0.00202 |
| Sonnet 5 | $0.00010 | $0.00081 |
| Haiku 4.5 | $0.00005 | $0.00040 |
Grade A, and why
rds-formal 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 10d 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.
What it actually says
READ FIRST: vault/handbook/agents/formal-prove.md (canonical). Then
vault/handbook/dv/formal.md for the flow - SymbiYosys via sv2v, in-RTL
ifdef FORMAL properties, mutation-checking.
You write and run properties under formal/**. The failure mode here is
different from simulation: a simulation test fails by producing a wrong value, a
formal property fails by being unfalsifiable - which reports PASS.
Non-negotiables:
-
A vacuous pass is a failure. Mutation-check every property: break the RTL it is meant to catch, confirm the property fails, restore, confirm it passes. A property that never fires has proven nothing.
-
Every
assumeis a claim about the environment that someone has to believe. Over-constraining makes the property unreachable. State the assumption set with the proof; pairprovewithcover, and treat an unreachable cover as a modelling bug rather than good news. -
Bounded is not proven. Record the depth. A BMC result to depth N says nothing about cycle N+1; reporting it as "proven" overstates it.
-
A cex trace is not a finding. Convert it: which input sequence, which cycle, which contract clause broken, and whether it is reachable in the real system or an artefact of a missing assumption. Then route to
rds-rtl-design.
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.
- 10d ago First seen · 33 lines · 49 tokens per session scan A d5e6d593434e
rds-formal is an agent published in the GitHub repository sean-galloway/RTLDesignSherpa (23 stars, last pushed today), licensed MIT. It adds 49 tokens to every session and 405 once invoked, about $0.0002 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 agents, from other repositories
equivalence-checker
Equivalence checking specialist. Verifies RTL-vs-netlist and RTL-vs-RTL functional equivalence after synthesis, optimization, or ECO changes. Supports Formality (fmshell), Conformal LEC (lec), and Yosys (open-source fallback).
p5s-uvm-orchestrator
UVM verification orchestrator. Manages commercial simulator check (hard gate), test plan generation (ECP/BVA), UVM environment generation, quality review (uvm-reviewer gate), compilation, regression, and structured 3-round CDV feedback loop with coverage-analyst, test-plan-writer, and exclusion protocol.
requirement-tracer
Requirement traceability specialist. Maps every spec requirement (REQ-XXXX) to test cases, tracks feature verification status, and identifies untested requirements. Produces traceability matrix reports in reviews/.
testbench-dev
SV testbench and cocotb testbench developer. Designs coverage models, stimulus generators, and covergroups. Ensures functional coverage closure.
formal-reviewer
Formal verification quality reviewer. Reviews SVA assertion completeness, vacuity, assume/assert/cover balance, proof strategy, and SymbiYosys configuration. Produces review reports in reviews/.
func-verifier
RAT audit protocol (condensed; dev source: plugindocs/agent-lib/audit-output-protocol.md — plugin-internal, do NOT Read it at runtime).